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1. the syntax are omitted see Irie Pascal Grammar for the full syntax statement label simple statement structured statement actual parameter expression variable access procedure identifier function identifier actual parameter list actual parameter actual parameter assignment statement assignment statement lhs expression assignment statement lhs variable access function identifier property designator case statement case case index case body end compound statement begin statement sequence end conditional statement else part else statement empty statement for statement do statement goto statement goto label if statement 1if boolean expression label digit sequenc if statement for control variable case statement initial value to downto final value then statement else part identifier procedure identifier identifier procedure method identifier identifier procedure method specifier object variable procedure method identifier procedure method statement procedure method specifier actual parameter list procedure statement procedure identifier actual parameter list read parameter list readln parameter list write parameter list writeln parameter list repeat statement repeat s repetitive statement
2. Portability Operating Systems Al1l Standard Pascal No 7 4 13 The dispose procedure Description The dispose procedure destroys an identified variable associated with a pointer variable or all of the selected variables associated with a list variable or an instance variable associated with an object variable The dispose procedure will store an undefined value into the pointer variable or the list variable or the object variable Parameter The dispose procedure s only parameter is a reference to a pointer variable or a list variable or a object variable It is an error if the variable referenced by the parameter contains the special value nil or is undefined Portability Operating Systems All Standard Pascal Yes In Standard Pascal the dispose procedure s parameter is an expression of pointer type and not a reference to a pointer variable as required by Irie Pascal Standard Pascal does not support list types or object types and so does not support using the dispose procedure on variables of those types 7 4 14 The erase procedure Description The erase procedure deletes a file Parameter The erase procedure s only parameter is a reference to a file variable This file variable must be named see the built in procedure assign and can not be open Example J RRR KR RK KKK IKK kk k k k k k k k k k k k k k k k k k A k k k k k k k k k k k k This program removes i e erases
3. abs 10 returns 10 abs 6 7 returns 6 7 abs 6 7 returns 6 7 Portability Operating Systems Al1l Standard Pascal Yes 7 2 3 The addr function Description The addr function returns the operating system address of the parameter passed to it The type of the value returned by this function is address This function is most often used when calling external functions and procedures Parameter The addr function s only parameter is a reference to the variable whose address is to be returned Portability Operating Systems All Standard Pascal No 7 2 4 The arctan function Description The arctan function returns the arctangent in radians of the parameter passed to it So if X is the parameter passed to this function then the value returned by this function Y is the angle in radians satisfying the following equation X tan Y The type of the value returned by this function is always real Parameter The arctan function s only parameter is a numeric expression 1 e an expression of integral type or of real type Example arctan 0 5 returns 4 64E 1 Portability Operating Systems Al1l Standard Pascal Yes 7 2 5 The chr function Description The chr function returns the character whose ordinal value is equal to the parameter passed to it So if X is the parameter passed to this function then the value returned by this function Y is the character value satisfying the following equation X ord Y
4. actual parameter list actual parameter actual parameter adding operator or or _else xor array type array index type list of component type array variable variable access assignment statement assignment statement lhs expression assignment statement lhs variable access function identifier property designator base type ordinal type binary digit 0 1 binary digit sequence binary digit binary digit binary integer S binary digit sequence block declarative part statement part boolean expression expression buffer variable file variable file variable c string type cstring max string length case body case list elements case statement completer case statement completer case constant ordinal constant case constant list case specifier case specifier case index ordinal expression case list element case constant list statement case list elements case list element case list element case specifier case constant case constant case statement case case index case body end case statement completer otherwise else statement sequenc character code digit sequence character literal string element one string element two character code component type type denoter component variable indexe
5. binary digit sequence binary digit binary digit binary digit 0 1 2 8 2 1 What are real numbers A Real number represents a numeric value with a fractional parts the fractional part may be zero Irie Pascal supports real numbers with values between about 1e308 and about 1e308 Examples 123 456 1 23456e2 which is also equal to 123 456 1 23456e02 which is also equal to 123 456 123456 0e 3 which is also equal to 123 456 7e 1 which is equal to 0 7 Syntax real number digit sequence fractional part exponent scale factor digit sequenc xponent scale factor digit 0t TIn 2 3t 4r 5 6 7H B 9 digit sequence digit digit exponent e fractional part digit sequenc scale factor sign digit sequence sign 2 9 1 What are identifiers Identifiers are sequences of letters digits and underscores that start with a letter or an underscore _ NOTE Standard Pascal does not allow underscores in identifiers By default identifiers are not case sensitive so for example gradeand Gradeand GRADE are normally considered to be the same identifier NOTE There is a compiler option that will make reserved words and identifiers case sensitive Some programmers prefer case sensitive languages since these languages consider identifiers that differ only in case to be different identifiers This is often used to allow strongly related identifiers to have the same
6. Example Below is a simple program that uses two generic object references objExplorer and app to access some of the COM objects exposes by Internet Explorer and to start Internet Explorer and navigate to the IrieTools website program Explorer var objExplorer object app object begin objExplorer CreateObject InternetExplorer app objExplorer application app navigate http www irietools com 1 app quit dispose app dispose objExplorer end Application Below is a more useful example program that illustrates how to send an email using the CDONTS NewMail COM object that is installed with Microsoft IIS You can use a similiar program to send email if your webserver uses IIS program cdonts const NORMAL 1 var objMail object FromAddress ToAddress string begin write Enter the from address readin FromAddress write Enter the to address readin ToAddress objMail CreateObject CDONTS NewMail objMail from FromAddress objMail to ToAddress objMail subject Testing objMail Body This is a test message objMail Importance NORMAL objMail Send dispose objMail end The program could also be simplified as follows program cdonts const NORMAL 1 var objMail object FromAddress ToAddress begin write Enter the from address re
7. If the string value being written to the text file is shorter than the minimum width then it is padded with spaces on the left until it is the same length as the minimum width If the string value being written to the file is longer than the minimum width then the entire string value is written to the file unless the write parameter is of string type or of boolean type in which case the string value is truncated on the right to the same length as the minimum width When a function or procedure is called the calling code and the function or procedure being called must agree on three basic things 1 The way parameters of different types are passed 2 The way function return results are passed back to the calling code 3 The way the responsibility for cleaning up after the call is shared between the calling code and the function or procedure These agreements are called calling conventions Implementation defined features may differ between implementations but must be consistent for any particular implementation Implementation dependent features may differ between implementations and are not necessarily defined for any particular implementation Copyright Stuart King 2002 2005 All Rights Reserved
8. The third argument passed to the setsockopt function is an integer value that identifies the socket option whose value you want to set The socket options you are most likely to set are given below e SO BROADCAST This option is of type BOOL and indicates whether you can use the socket to send broadcast messages SO DEBUG This option is of type BOOL and indicates whether debugging is enabled SO_DONTLINGER This option is of type BOOL and indicates whether the SO_LINGER option is disabled SO _DONTROUTE This option is of type BOOL and indicates whether routine is disabled SO LINGER This opton is of type linger and sets the current linger options for the socket see the closesocket function for more information about linger options SO_OOBINLINE This option is of type BOOL and indicates whether OOB data will be received in the normal data stream Return Values The setsockopt function returns a value of integer type that indicates whether the call was successful A value of zero means that the call succeeded A value of SOCKET ERROR indicates that the called failed and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail NOTE The constant SOCKET ERROR is declared in the system include file WinSock2 inc Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSD
9. example this is an example example Portability Operating Systems Al1l Standard Pascal No Description The cos function returns the cosine of the parameter passed to it The type of the value returned by this function is always real Parameter The cos function s only parameter is a numeric expression i e an expression of integral type or of real type which is an angle in radians Example cos pi 3 returns Portability Operating Systems Al1l Standard Pascal Yes turns turns returns name val name val name val Turns Turns turns turns exampl exampl is as the deliminstor to extract fields from comma deliminated strings 1234 name value 7 2 9 The cos function 7 2 10 The cosh function Description The cosh function returns the hyperbolic cosine of the parameter passed to it The type of the value returned by this function is always real Parameter The cosh function s only parameter is a numeric expression i e an expression of integral type or of real type which is an angle in radians Portability Operating Systems All Standard Pascal No 7 2 11 The countwords function Description The countwords function accepts up to two of the parameters described below the last parameter is optional and returns a value of type integer type which is equal to the number of words in the first parameter The term word is used to mean a group o
10. s fexpand s getfilemode s mode isdir mode and dir bit lt gt 0 write Group permissions f mode and grp_r lt gt 0 then rite Read f mode and grp w lt gt 0 then rite Write f mode and grp x lt gt 0 then f isdir then te Search lse rite Execute riteln end K H SSO SHE EEE Portability Operating Systems Al1l Standard Pascal No 4 2 26 grp_ x Description grp_x can be AND d see and operator bitwise with the filemode retrieved by the built in procedure getfilemode to determine if any user belonging to the same group as the owner of a file or directory has permission to execute the file or search the directory Example For example the simple program below asks for a filename and then displays the group permissions for the file program GroupPermissions input output var s filename mode integer isdir boolean begin write Enter filename readin s s fexpand s getfilemode s mode isdir mode and dir bit lt gt 0 write Group permissions Al mode and grp_r lt gt 0 then write Read al mode and grp w lt gt 0 then write Write 1 mode and grp x lt gt 0 then if isdir then w e w w rite Search lse rite Execute riteln end Portability Operating Systems Al1l Standard Pascal No 4 2 27 maxbyte Description max
11. Assignments statements are made up of a left hand side and a right hand side seperated by the assignment operator The left hand side of an assignment statement is either a variable function identifier or a property of an instance variable see object variables for information about instance variables The right hand side of an assignment statement is an expression When a assignment statement is executed its right hand side is evaluated and its value is stored in the left hand side The value of the right hand side must be assignment compatible with the type of the left hand side NOTE Functions return values by assigning values to their function identifiers Example amp 1 1 is a simple example When this statement is executed the right hand side 1 1 is evaluated and the resulting value i e 2 is stored in the left hand side i e the variable x Syntax NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax assignment statement assignment statement lhs expression assignment statement lhs variable access function identifier property designator property designator object variable property specifier 9 4 Procedure statement Description Procedure statements execute procedures which may involve passing actual parameters to the procedures formal parameters Procedure statements are executed as follows 1 First the ac
12. Description null is the variable identifier for a special built in variable of type address which is implemented by Irie Pascal to make it easier to call certain external functions and procedures written in the C programming language In C there is no special mechanism for passing variables by reference instead the programmer must explicitly declare the formal parameter to be the address of a variable and pass the address of a variable as the actual parameter when making the call In Pascal there is a special mechanism i e var parameters for passing parameters by reference the programmer would declare the formal parameter as a var parameter but the call remains the same because the Pascal implementation will take take of the passing the address of the variable behind the scenes So when declaring in Pascal an external function or procedure written in C that passes variables by reference it is natural to use var parameters for the variables passed by reference In most cases this works great and Irie Pascal will take care of the details however in the following special case there is a problem Neither C not Pascal support optional parameters at least not in the standard versions of these languages however in C because addresses are being passed explicity and an address is just a value it is possible to pass special values to mean that the parameter was not passed In C the special value zero called the null pointer is usu
13. This program uses the built in procedure getfilemode to determine if a file is a directory program isdirectory input output var s filename mode integer isdir boolean begin write Enter filename readin s s fexpand s getfilemode s mode isdir mode and dir bit lt gt 0 if isdir then writeln s is a directory else writeln s is not a directory end Portability Operating Systems Al1l Standard Pascal No 7 4 24 The getfiletime procedure Description The getfiletime procedure retrieves the modification time of a file Parameter 1 The first parameter is an expression of string type or char type which is the name of the file whose modification time is to be retrieved 2 The second parameter is a reference to a variable of integer type or word type which will store the hour the file was last modified 3 The third parameter is a reference to a variable of integer type or word type which will store the minute the file was last modified 4 The fourth parameter is a reference to a variable of integer type or word type which will store the second the file was last modified Example Suppose the file c irie readme txt was last modified at 2 45 05 P M then after getfiletime c irie readme txt hour minute second hour 14 minute 45 second 5 Portability Operating Systems Al1l Standard Pascal No 7 4 25 The gettime pro
14. address main street grade 20 end is equivalent to begin s name John s address main street s grade 20 end Since some record types can contain other record types you can have nested with statements like the following with recordl do with record2 do with record3 do statement or you can use the following shorthand which does the same thing with recordl record2 record3 do statement Syntax NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax with statement with record variable list do statement record variable list record variable record variable 9 13 Procedure method statement Description Procedure method statements are similiar to procedure statements the only difference is that the procedures executed by procedure method statements are methods of instance variables see object variables for more information about instance variables instead of normal procedures Syntax NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax procedure method statement procedure method specifier actual parameter list actual parameter expression variable access procedure identifier function identifier actual parameter list actual parameter actual parameter procedure method identifier identifier procedure method spe
15. green 2 cyan 3 red 4 magenta brown 6 white 7 grey 8 light_blue 9 light _green 10 light cyan 11 light red 12 light magenta 13 yellow 14 high intensity white 15 Chock ch scr oct SW44 begin textcolor white write White text textcolor light green write Light green text textcolor white writeln White text end Portability Operating Systems Windows only Standard Pascal No 7 4 59 The traperrors procedure Description The traperrors procedure turns automatic error trapping on or off If automatic error trapping is on and a trappable error occurs then the program is terminated and an error message may be printed on the console screen displayed in a message box and or logged to a file depending on the project setting when the program was compiled If automatic error trapping is off and a trappable error occurs then one or more records of type error are created and added to the built in list variable errors Each error record describes the error that occured some in more detail than others Also the built in function getlasterror will return a non zero value to indicate which category of error occured If you do not want the program to be terminated when a trappable error occurs and prefer to handle the error yourself then turn automatic error trapping off with TrapErrors false before executing code that may c
16. is Factor t type denoter t end le variable access le list record variable record variable list y variable access variable access relational operator lt gt lt lt gt gt in repeat statement repeat statement sequence until boolean expression repetitive statement repeat statement while statement for statement ki result type type identifier scale factor sign digit sequence selected variable list variable index expression index expression set constructor member designator member designator set type set of base type shift expression simple expression shift operator simple expression shift operator shl shr sign al t ty simple expression term adding operator term simple statement empty statement assignment statement procedure statement procedure method statement goto statement statement label simple statement structured statement statement part compound statement statement sequence statement statement string element one printable character string element two printable character string expression expression string literal empty string non empty string string type pascal string type c string type string variable variable access structured state
17. platform win32 writeln Windows platform linux writeln Linux platform fbsd writeln FreeBSD platform solaris writeln Solaris x86 platform solaris sparc writeln Solaris Sparc platform error writeln Unknown Platform end end Portability Operating Systems Al1l Standard Pascal No 4 2 39 platform_os2 Description platform_os2 can be compared with the value returned by the built in function platform to determine whether the current platform is OS 2 i e the interpreter running your program is from the OS 2 edition of Irie Pascal Example The following simple program displays the current platform program ShowPlatform output begin case platform of platform dos writeln DOS platform_os2 writeln 0S 2 platform _win32 writeln Windows platform linux writeln Linux platform fbsd writeln FreeBSD platform solaris writeln Solaris x86 platform solaris sparc writeln Solaris Sparc platform error writeln Unknown Platform end end Portability Operating Systems Al1l Standard Pascal No 4 2 40 platform_solaris Description platform_solaris can be compared with the value returned by the built in function platform to determine whether the current platform is Solaris x86 i e the interpreter running your program is from the Solaris x86 edition of Irie Pascal Example The following simple program displays
18. Description The eof function tests whether a file is at end of file and returns a value of boolean type that indicates the result of the test If the file tested is at end of file then the value true is returned and if the file tested in not at end of file then the value false is returned Parameter The eof function s optional parameter is a reference to a file variable If the optional parameter is supplied then the eof function tests the file associated with the parameter If the optional parameter is not supplied then the file associated with the built in variable input is tested Example The function below counts the number of lines in a text file The eof function is used to determine when the end of the text file has been reached function CountLines name filename integer var count integer fF text begin count 0 reset f name while not eof f do begin readin f inc count end CountLines count close f end Portability Operating Systems Al1l Standard Pascal Yes 7 2 15 The eoln function Description The eoln function tests whether a text file is at end of line and returns a value of type boolean that indicates the result of the test If the file tested is at end of line then the value true is returned and if the file tested in not at end of file then the value false is returned Parameter The eoln function s optional parameter is a reference to a file variab
19. Description The tan function returns the tangent of the parameter passed to it The type of the value returned by this function is always real Parameter The tan function s only parameter is a numeric expression i e an expression of integral t or of real yp expression p integral type type which is an angle in radians Example tan pi 4 returns 1 0 Portability Operating Systems Al1l Standard Pascal No 7 2 66 The tanh function Description The tanh function returns the hyperbolic tangent of the parameter passed to it The type of the value returned by this function is always real Parameter The tanh function s only parameter is a numeric expression i e an expression of integral type or of real type which is an angle in radians Example tanh 1 returns 0 762 Portability Operating Systems Al1l Standard Pascal No 7 2 67 The trim function Description The trim function returns a string formed by removing all leading and trailing spaces from the parameter passed to it Parameter The trim function s only parameter is an expression of string type or char type Example trim hello returns hello Portability Operating Systems Al1 Standard Pascal No 7 2 68 The trunc function Description The trunc function truncates the parameter passed to it i e returns the integer number part of the the parameter The type of the value returned by this function is always integer
20. Sak returns true lt a return true Tal lt return false 8 4 4 4 Is greater than Description When the gt operator has two numeric operands it compares their values after applying the numeric type conversion rules The result of this operation is of boolean type and is true if the left operand is greater than the right operand and false otherwise When the gt operator has two operands of char type or of string typethen the char string type conversion rules are applied and then the lexical ordering of the operands are compared The result of this operation is of boolean type and is true if the left operand is greater than the right operand and false otherwise Example For example abc gt abc results in false abc gt abcd results in false abc gt ap results in true abc gt abd results in false tabet gt taac results in true tapet gt p results in false 8 4 4 5 Is greater than or equal Description When the gt operator has two numeric operands it compares their values after applying the numeric type conversion rules The result of this operation is of boolean type and is true if the left operand is greater than or equal to the right operand and false otherwise When the gt operator has two operands of char type or of string typethen the char string type conversion rules are applied and then the lexical ordering of the operands are compared T
21. The first parameter is a reference to the directory variable to open The second parameter is an expression of string type or char type and is the name of the directory to associate with the directory variable Example Below is a simple program that lists all the files in the current directory program listfiles output var d dir filename string begin opendir d Open current directory repeat readdir d filename Get next file in directory if filename lt gt then writeln filename until filename closedir d Close directory end Portability Operating Systems Al1l Standard Pascal No 7 4 37 The pack procedure Description The pack procedure assigns values to all the elements of a packed array by copying some or all of the elements of an unpacked array into the packed array The elements of both arrays must have the same type Parameter The first parameter is a reference to the unpacked array variable that contains the array elements to copy The second parameter is an expression of ordinal type that specifies the start element of the unpacked array 1 e the element of the unpacked array to start copying from The elements from the start element of the unpacked array to the last element of the unpacked array are available to be copied into the packed array It is an error if the number of elements in the unpacked array available to be copied into t
22. directive rocedure identification procedure block p p p procedure heading procedure block block declarative part statement part compound statement begin statement sequence end declaration group label declaration group constant definition group type definition group variable declaration group function declaration procedure declaration declarative part declaration group directive forward directive external directive formal parameter list formal parameter section formal parameter section formal parameter section value parameter specification variable parameter specification procedure parameter specification function parameter specification function block block function heading function identifier formal parameter list result type Function identification function function identifier function identifier identifier function parameter specification function heading identifier letter letter digit identifier list identifier identifier procedure block block procedure heading procedure identifier formal parameter list procedure identification procedure procedure identifier procedure identifier identifier procedure parameter specification procedure heading result type type identifier statement part compound stat
23. open file variable filename readmodetwritemode open for reading and writing open file variable filename readmode or writemode open for reading and writing Portability Operating Systems Al1l Standard Pascal No writemode 4 2 59 1 The feature constants Irie Pascal supports several built in constants that an application can pass to the built in function supported to determine if particular features are available on the current platform One approuch is to have your application check on start up to make sure all necessary features are available If a necessary feature is not available your application could then report which feature is missing and abort Another approuch is to have your application run with reduced functionality if certain features are not available For example an application could pass the feature_odbc constant to the supported function to determine if ODBC is supported before attempting to use ODBC to connect to a database The feature constants are listed below feature_calldll feature_closedir feature_clrscr feature_delay feature_gotoxy feature_idispatch feature_intr feature_keypressed feature_mysql feature_odbc feature_opendir feature_popen feature_readdir feature_readkey feature_rewinddir feature_textbackground feature_textcolor feature_wherex feature_wherey 4 2 60 1 The file mode constants Irie Pascal supports three integer constants which can be used w
24. procedure heading procedure identifier formal parameter list value parameter specification identifier list type identifier variable parameter specification var identifier list 7 4 1 The built in procedures formal parameter list formal parameter section formal parameter section result type type identifier The built in procedures are procedures that are automatically declared by the compiler and each built in procedure is associated with a built in procedure identifier Unlike reserved words you can declare your own identifiers with the same spelling as a built in procedure identifier and if you do so then your declaration will override the declaration made by the compiler The built in procedure identifiers are listed below The append procedure The assert procedure The assign procedure The chdir procedure The close procedure The closedir procedure The clrscr procedure The cre32 procedure The dec procedure The delay procedure The delete procedure The dispose procedure The erase procedure The exec procedure The exit procedure The fill procedure The flush procedure The fsplit procedure The get procedure The getdate procedure The getfiledate procedure The getfilemode procedure The getfiletime procedure The gettime procedure The gotoxy procedure The halt procedure The inc procedure The insert procedure The intr procedure The mkdir procedure The move procedure Th
25. 1 upcase returns upcase _ returns _ Portability Operating Systems Al1l Standard Pascal No 7 2 71 The uppercase function Description The uppercase function returns a string formed by converting all lowercase characters in the parameter passed to it into uppercase characters and leaving all non lowercase characters in the parameter unchanged Parameter The uppercase function s only parameter is an expression of string type or char type Example uppercase Hello returns HELLO Portability Operating Systems Al1l Standard Pascal No 7 2 72 The urldecode function Description The urldecode function returns a string formed by decoding the URL encoded string passed as it s parameter URL decoding is a simple two step process First all plus characters are converted to spaces Second all hexadecimal sequences like xx are converted to the equivalent binary character This function can be useful in Common Gateway Interface CGI programs for processing GET or POST methods since these methods URL encode strings Parameter The urldecode function s only parameter is an expression of string type or char type Example urldecode irietpascal returns irie pascal urldecode 2Fusr 2Flocal 2Fbin returns usr local bin Portability Operating Systems Al1l Standard Pascal No 7 2 73 The version function Description The version function returns the version number
26. 18 3 Accessing inactive variant 18 4 Dereferencing nil pointers 18 5 Dereferencing undefined pointers 18 6 Dangling pointers 18 7 Altering file variab l 18 8 Using out of range value parameters 18 9 Using out of range set value parameters 18 10 Output to file not open for writing 18 11 Output to undefined file 18 12 Writing to middle of fil 18 13 Using Put on undefined buffer variables 18 14 Resetting undefined files 18 15 Input from file not open for reading 18 16 Input from undefined file 18 17 Reading past end of file 18 18 Reading out of ran l 18 19 Writing out of range values 18 20 new p c1 cN constraints violated 18 21 Incompatible use of dispose p 18 22 Incompatible use of dispose p k1 kM 18 23 di k1 kM constraint violation 18 24 disposing nil pointer 18 25 disposing undefined pointer 18 26 new p cl cM constraint violated 18 27 Invalid use of pack 1 18 28 Invali f pack 2 18 29 Invalid use of pack 3 18 30 Invalid use of unpack 1 18 31 Invalid use of unpack 2 18 32 Invalid use of unpack 3 1 re of large number 18 34 In x and x is less than or equal to 0 18 35 Square root of negative number 18 36 Problems with trunc 18 37 Problems with round 1 Problems with chr 18 39 Problems with succ 18 40 Problems with pred 18 41 Using eof on undefined files 18 42 Using eoln on undefined files 18 43 Using eo
27. 7 2 41 The lowercase function Description The lowercase function returns a string formed by converting all uppercase characters in the parameter passed to it into lowercase characters and leaving all non uppercase characters in the parameter unchanged Parameter The lowercase function s only parameter is an expression of string type or char type Example lowercase Hello returns hello Portability Operating Systems Al1l Standard Pascal No 7 2 42 The odd function Description The odd function returns a value of type boolean which indicates whether the parameter passed to it is odd i e not evenly divisible by two If the parameter is odd then the value true is returned and if the parameter is not odd then the value false is returned Parameter The odd function s only parameter is an expression of integral type Example odd 0 return false odd 1 return true odd 2 return false odd 43 return true odd 44 return false Portability Operating Systems Al1l Standard Pascal Yes 7 2 43 The ord function Description The ord function returns the ordinal value of the parameter passed to it The type of the value returned by this function is always integer Parameter The ord function s only parameter is an expression of ordinal type Example ord false returns 0 ord true returns 1 ord 21 returns 21 ord A returns 65 assuming the ASCII or ANSI character
28. If the connect function has been used previously on the socket that you are sending the data through to specify a default destination socket or default destination sockets then this argument can be zero if you want to send the data to the default destination socket or sockets this argument can override the default destination socket or sockets for the current datagram only and specify the name of a destination socket or destination sockets that should receive the data being sent The name specified by this argument can be any valid name in the socket s address family including a name with broadcast or multicast addresses To send data to a broadcast address your program must have previously used the setsockopt function with SO_BROADCAST enabled Otherwise the sendto function will fail and if you then call the WSAGetLastError function to find out the reason for the failure the error code returned will be WSAEACCES For TCP IP sockets your program can send to any multicast address The following rules apply when sending broadcast datagrams through sockets from the Internet Address Family To send a broadcast through SOCK_DGRAM sockets only the address in this argument should be the special IP address IVADDR_BROADCAST Broadcast datagrams should not exceed the size at which fragmentation can occur which implies that the data portion of the datagram excluding headers should not exceed 512 bytes This argument is ign
29. Lewmak begin for 1 1 to max do numbers i random 100 1 end procedure SortNumbers var 1 1 max swapped boolean temp integer begin repeat swapped false for i 1 to max 1 do if numbers i gt numbers it l then begin temp numbers i numbers i numbers itl numbers i 1 temp swapped true end until not swapped end procedure PrintNumbers var io 1 max begin for i 1 to max do writeln i numbers i end begin randomize GenerateRandomNumbers SortNumbers PrintNumbers end Syntax See array types for the syntax for defining new array types The syntax for referencing array elements i e indexed variables is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax indexed variable indexed variable array indexed variable string array variable variable access index expression expression indexed variable array array variable index expression index expression la Where array variable is a reference to an array variable and index expression is an expression which evaluates to one of the values specified by the array s index type 6 6 File variables Description File variables are used to process files i e create destroy change or retrieve values from files The term file is a shorthand way of saying collection of values defined by a file type
30. Portability Operating Systems Al1l Standard Pascal No 7 4 5 The chdir procedure Description The chdir procedure changes the current directory NOTE Directories are also called folders Parameter The chdir procedure s only parameter is an expression of string type or char type which is the name of the directory to change to Example chdir irie samples changes the current directory to irie samples Portability Operating Systems Al1l Standard Pascal No 7 4 6 The close procedure Description The close procedure closes a file variable and the file or pipe associated with it Before the file variable is closed it is flushed as if the built in procedure flush was called NOTE The file variable must be open when this procedure is called Parameter The close procedure s only parameter is a reference to the file variable to close Example function CountLines name filename integer var count integer fF text begin count 0 reset f name while not eof f do begin readin f inc count end CountLines count close f end Portability Operating Systems Al1 Standard Pascal No 7 4 7 The closedir procedure Description The closedir procedure closes a directory variable i e destroys the association between a directory variable and it s directory NOTE Directories are also called folders Parameter The closedir procedure s only parameter is a referen
31. Return Values The htonl function returns the u_long value in TCP IP network byte order Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 16 6 The htons function Description The htons function converts a value of type u_short from host to TCP IP network byte order which is big endian Declaration The system include file WinSock2 ince contains the following declarations for the u_ short type and the htonl function u_short shortint function htonl hostlong u_long u_long external dll ws2_32 d11 Arguments The only argument passed to the htons function is the u_short value that you want to convert to TCP IP network byte order Return Values The htons function returns the u_short value in TCP IP network byte order Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 16 7 The inet_addr function Description The inet_addr function converts a host address from a null terminated string into a numeric value Declaration The system include file WinSock2 ine contains the following declaration for the inet_addr function function inet_addr cp address u_long external dll ws2_32 d11
32. The following built in functions and procedures operate on file variables Most file variables are associated with buffer variables File variables of type text are associated with buffer variables of type char File variables of other types except binary are associated with buffer variables whose type is the same as the component type of the file variables type File variables of type binary do not have a particular component type and so they do not have buffer variables Example The simple example program below uses a file variable f to create a file called numbers dat and write the numbers 1 to 10 to the file program numbers var f file of integer i integer begin assign f numbers dat rewrite f 1 to 10 do i for i write f end Syntax The syntax for referencing file variables is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax file variable variable access 6 5 Buffer variables Description Most file variables have an associated buffer variable which provides direct access to the next value waiting to be read from the file or the next value to be written to the file In Standard Pascal i e ISO IEC 7185 file variables can be opened in one of two modes 1 Inspection read only mode see reset 2 Generation write only mode see rewrite When a file variable is opened in read only mode the contents of the b
33. a file associated with a file variable of type text and the way the values are read is determined by the type of the variable used to store the values Ifa variable of char type or a subrange of char type is being used to store the values read from the text file then a single character is read from the text file and this character is stored without conversion in the variable Ifa variable of string type is being used to store the values read from the text file then characters are read from the text file and stored in the variable until either the end of the line is reached or the number of characters stored in the variable is equal to the maximum number of characters that can be stored in the variable Ifa variable of an integral type or a subrange of an integral type is being used to store the values read from the text file then a sequence of characters forming a signed decimal integer number possibly with leading blanks is read from the file and converted into the equivalent value of integer type before being stored in the variable e Ifa variable of real type single type or double type is being used to store the values read from the text file then a sequence of characters forming a signed real number possibly with leading blanks is read from the file and converted into the equivalent value of real type before being stored in the variable Example For file example the program batch pas below is a very pr
34. mode isdir mode and dir bit lt gt 0 write Other permissions f mode and oth_r lt gt 0 then rite Read f mode and oth _w lt gt 0 then rite Write f mode and oth _x lt gt 0 then f isdir then te Search lse ite Execute riteln end K H ry a Oe Portability Operating Systems Al1l Standard Pascal No 4 2 34 oth x Description oth_x can be AND d see and operator bitwise with the filemode retrieved by the built in procedure getfilemode to determine whether users not belonging to the same group as the owner of a file or directory has permission to execute the file or search the directory Example For example the simple program below asks for a filename and then displays the file permissions for users who not belong to the same group as the owner of the file program OtherUsersPermissions input output var s filename mode integer isdir boolean begin write Enter filename readin s s fexpand s getfilemode s mode isdir mode and dir bit lt gt 0 write Other permissions if mode and oth_r lt gt 0 then write Read if mode and oth_w lt gt 0 then write Write if mode and oth_x lt gt 0 then if isdir then write Search else write Execute writeln end Portability Operating Systems Al1l Standard Pascal No 4 2 35 pl
35. multiplication Real division Integer division div Modulus mod Is equal Is not equal lt gt Is less than lt Is less than or equal lt Is greater than gt Is greater than or equal gt xor boolean String concatenation Set union Set difference Set intersection Set inclusion in and bitwise or bitwise xor bitwise Bit shift left shl Bit shift right shr Irie Pascal always evaluates the operands of the following operators using short circuit evaluation and then boolean or else boolean Irie Pascal evaluates the operands of the following operators using short circuit evaluation if short circuit evaluation is enabled or left to right if short circuit evaluation is disabled and boolean or boolean 17 7 Order of evaluation of actual parameters for function calls 6 7 3 The order of evaluation accessing and binding of the actual parameters of a function designator is implementation dependent In other words the order in which the actual parameters are evaluated and passed to the formal parameters during a functions call is implementation dependent Irie Pascal evaluates and passes actual parameters from left to right 17 8 Order of evaluating components of assignment statements 6 8 2 2 The order of accessing the variable and evaluating the expression of an assignment statement is implementation dependent Program
36. string var sValue string begin write sPrompt readin sValue GetStringValue sValue end begin if supported feature_ odbc then begin sDSN GetStringValue Enter Data Source Name DSN sUser GetStringValue Enter user id sPassword GetStringValue Enter password s ODBC DSN sDSN user sUsert password sPassword end else if supported feature mysql then begin sUser GetStringValue Enter user id sPassword GetStringValue Enter password s MYSQL user sUsert password sPassword socket tmp mysql sock end else DisplayError No database support detected GetConnectionString s end begin new conn conn open GetConnectionString Add code here to process database conn close dispose conn end Syntax The syntax for accessing an object property is give below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax property designator object variable property specifier object variable variable access property identifier identifier property specifier property identifier property string property string string expression where string expression is an expression of type string which evaluates to the name of the property The preferred form of a property reference is just to use the property nam
37. the corresponding actual parameters are variables and the addresses of these variables are passed into the variable parameters Subroutines reference variable parameters just like normal variables however references to variable parameters actually reference the variables passed as the corresponding actual parameters Function parameters are passed by reference i e when subroutines with function parameters are called the corresponding actual parameters are functions and the addresses of these functions are passed into the function parameters Subroutines can call function parameters just like normal functions however calling function parameters actually calls the functions passed as the corresponding actual parameters Procedure parameters are passed by reference i e when subroutines with procedure parameters are called the corresponding actual parameters are procedure and the addresses of these procedure are passed into the procedure parameters Subroutines can call procedure parameters just like normal procedure however calling procedure parameters actually calls the procedure passed as the corresponding actual parameters Example For example here is an example of a simple program with a procedure program simple output procedure say message string begin writeln message end begin say Hello world say Good bye end The program contains a procedure called say which takes a single value parameter When t
38. the value of socket option SO_MAX MSG_SIZE If the data is too long to pass atomically through the underlying protocol the error WSAEMSGSIZE is returned and no data is transmitted Declaration The system include file WinSock2 ine contains the following declaration for the send function function send s SOCKET buf address len flags integer integer external dll ws2_32 d11 Arguments The First Argument The first argument passed to the send function is the socket that you want to send data through The Second Argument The second argument passed to the send function is the operating system address of the buffer containing the data to be sent through the socket The type of this argument is address which means that you must use the built in function addr to pass the operating system address of the buffer The Third Argument The third argument passed to the send function is the number of bytes of data to be sent through the socket This argument can be zero and this case will be treated by implementations as successful and send will return zero as a valid value If the socket is connectionless a zero length transport datagram is sent The Fourth Argument The fourth argument passed to the send function can specify flags which influence the behavior of the send function The flags can be OR d or added together if more than one flag is being specified The flags which can be used are MSG _DONTROUTE Specifie
39. var unpacked value array 1 10 of integer packed value packed array 21 30 of integer then pack unpacked value 2 packed value means that the pack procedure should attempt to transfer ten elements from the unpacked array since the packed array has ten elements starting with the element two So the pack procedure should transfer elements 2 11 from the unpacked array but the unpacked array does not have an element 11 Error Handling This error is always reported 18 30 Invalid use of unpack 1 Official Description 6 6 5 4 For unpack it is an error if the parameter of ordinal type is not assignment compatible with the index type of the unpacked array parameter Simplified Description In other words the parameter used to specify the first element of the unpacked array to receive elements transferred from the packed array must be assignment compatible with the index type of the unpacked array Or to put it another way the first element of the unpacked array to receive elements transferred from the packed array must exist For example given var unpacked value array 1 10 of integer packed value packed array 21 30 of integer then unpack packed _ value unpacked value 0 is an error since 0 is not assignment compatible with 1 10 Or to put it another way element 0 of the unpacked array does not exist Error Handling This error is always reported 18 31 Invalid use of unpack 2 Official
40. which the statements in a program are executed cause some statements not to be executed at all or cause some statements to be executed more than once Pascal programs always begin executing at the first statement in the main program block Statements can be grouped in a number of ways For example statements can be separated into two groups simple statement and structured statements where simple statements are statements that do not contain other statements while structured statements are statements that do contain other statements Statements can also be grouped according to the kind of action they perform such as conditional statements and repetitive statements Conditional statements allow programs to make decisions i e they test a particular condition and transfer program execution depending on the result Repetitive statements allow the program to loop i e transfer program execution to the same statement or statements repeatedly Labels can be placed in front of statements to mark them as targets for goto statements As an extension to Standard Pascal Irie Pascal allows labels to be identifiers as well as sequences of digits The statements are e Empty statement e Assignment statement Procedure statement Goto statement Compound statement If statement Case statement Repeat statement While statement For statement With statement Procedure method call Syntax NOTE for clarity some parts of
41. x will contain ABCDEF and after x ABFGHI insert CDE x 3 insert CDE at the third position x will contain ABCDEFGHI Portability Operating Systems Al1l Standard Pascal No 7 4 30 The intr procedure Description The intr procedure generates a x86 processor interrupt Parameter 1 The first parameter is an expression of integral type whose value is the number of the interupt to generate 0 255 2 The second parameter is a reference to the variable of registers type which contains values to pass into the x86 processor registers before the interrupt is generated and which receives the contents of the x86 processor registers after the interrupt is serviced Example For example the following simple program uses interrupt 10 to clear the screen program cls var regs registers begin fill regs 0 regs eax 0002 intr 10 regs end Portability Operating Systems DOS only Standard Pascal No 7 4 31 The mkdir procedure Description The mkdir procedure creates a new directory folder If the directory folder already exists then the mkdir procedure call will fail Parameter 1 The first parameter is an expression of string type or char type which is the name of the directory folder to create If the directory folder being created is a sub directory sub folder then the parent directories folders must exist 2 The second parameter is optional and if sup
42. 1 Constant definition 5 Types 5 1 What are types 5 2 Array types 5 3 Enumerated types 5 4 File types 5 5 Integral types 5 6 List types 5 7 Ordinal types 5 8 Pointer types 5 9 Record types 5 10 Set types 5 11 String types 5 12 Subrange types 5 13 Variant Types 5 14 Object Types 5 14 1 What are object types 5 14 2 Generic objects 5 15 Built in Type Identifiers 5 15 1 The built in type identifiers 5 15 2 address type 5 15 3 binary type 5 15 4 boolean type 5 15 5 byte type 5 15 6 char type 1 ir 5 15 8 double type 5 15 9 error type 5 15 10 filename type 5 15 11 integer type 5 15 12 real type 5 15 13 registers type 5 15 14 regtype type 5 15 15 shortint type 5 15 16 shortword type 5 15 17 single type 5 15 18 text type 5 15 19 word type 5 15 20 Connection Type 5 15 20 1 The connection type 5 15 20 2 connection close 5 15 20 3 connection execute 5 15 20 4 connection open 5 15 20 5 connection selectdatabase 5 15 20 6 connection databasename 5 15 20 7 connection dbmsname 5 15 20 8 connection dbmsver 5 15 20 9 connection dmver 5 15 20 10 connection odbcver 5 15 20 11 connection procedures 5 15 20 12 connection readonly 5 15 20 13 connection transactions 5 15 20 14 connection transsupport 5 15 21 Recordset Type 5 15 21 1 The recordset type 5 15 21 2 recordset close 15 21 3 recordset moreresult 5 15 21 4 recordset movenext 5 15 21 5 records
43. 1 Th lean operator 8 4 5 2 not boolean 8 4 5 3 and boolean 8 4 5 4 and_then boolean 8 4 5 5 or boolean 8 4 5 6 or else boolean 8 4 5 7 xor boolean 8 4 6 String Operators 8 4 6 1 The string operators 8 4 6 2 String concatenation 4 t rator 8 4 7 1 The set operators 8 4 7 2 Set union 8 4 7 3 Set difference 8 4 7 4 Set intersection 8 4 7 5 Set inclusion in 8 4 8 Bitwise Operators 8 4 8 1 The bitwise operators 8 4 8 2 not bitwise 8 4 8 3 and bitwise 8 4 8 4 or bitwise 8 4 8 5 xor bitwise 8 4 8 6 Bit shift left shl 8 4 8 7 Bit shift right shr 9 Statements 9 1 What are statements 2 Empty statement 9 3 Assignment statement 9 4 Procedure statement 9 5 Goto statement 9 6 Compound statement 9 7 If statement 9 8 Case statement 9 9 Repeat statement 9 10 While statement 9 11 For statement 9 12 With statement 9 13 Procedure method statement 10 Pascal Compatibility Rules 10 1 Compatible types 10 2 Assignment Compatibilty 10 2 1 What is assignment compatibility 10 2 2 Assignment compatibility with array indexing 10 2 3 Assignnment compatibility with value parameters 10 2 4 Assignment compatibility with read 10 2 5 Assignment compatibility with assignment statements 10 2 6 Assignment compatibility with for 10 2 7 Assignment compatibility with transfer procedures 11 Program Parameters 11 1 What are program parameters
44. 6 6 5 3 For dispose p k1 kM it is an error unless the variable had been created using the form new p cl cN and m is equal to n Error Handling Irie Pascal does not support this form of the dispose procedure so this error can not occur 18 23 dispose p k1 kM constraint violations Official Description 6 6 5 3 For dispose p k1 kM it is an error if the variants identified by the pointer value of p are different from those specified by the case constants k1 kM Error Handling Irie Pascal does not support this form of the dispose procedure so this error can not occur 18 24 disposing nil pointer Official Description 6 6 5 3 For dispose it is an error if the pointer variable has a nil value Error Handling This error is always reported 18 25 disposing undefined pointer Official Description 6 6 5 3 For dispose it is an error if the pointer variable has an undefined value Error Handling This error is always reported 18 26 new p cl cM constraint violated Official Description 6 6 5 3 It is an error if a variable created using the second form of new is accessed by the identified variable of the variable access of a factor of an assignment statement or of an actual parameter Error Handling Irie Pascal does not support this form of the new procedure so this error can not occur 18 27 Invalid use of pack 1 Official Description 6 6 5 4 For pack it is an error if the parameter
45. Al1l Standard Pascal No 7 2 19 The filepos function Description The filepos function returns the current file position of a file The type of the value returned by this function is always integer Parameter The filepos function s only parameter is a reference to the file variable that specifies the file whose current file position is to be returned NOTE For a file variable of type text the value of the file position may not be equal to the number of characters read written to the file so far NOTE For file variable of other types the value of the file position is equal to the number of characters read written so far The file variable must refer to an open file Portability Operating Systems Al1l Standard Pascal No 7 2 20 The filesize function Description The filesize function returns the size in bytes of a file The type of the value returned by this function is always integer Parameter The filesize function s only parameter is a reference to the file variable that specifies the file whose size is to be returned NOTE The file variable must refer to an open file Portability Operating Systems A1l1 Standard Pascal No 7 2 21 The frac function Description The frac function returns the fractional part of the parameter passed to it The type of the value returned by this function is always real Parameter The frac function s only parameter is the expression of real type whose fractional part is to be r
46. DSN sDSN user sUsert password sPassword end else if supported feature mysql then begin sUser GetStringValue Enter user id sPassword GetStringValue Enter password s MYSQL user sUsert password sPassword socket tmp mysql sock end else DisplayError No database support detected GetConnectionString s end begin new conn conn open GetConnectionString fi Add code here to process database conn close dispose conn end Portability Operating Systems All Standard Pascal No 4 2 14 feature_odbc ODBC databases supported Description feature_odbc can be used to determine if the current platform supports using ODBC to connect to databases Example program Data input output var conn connection procedure DisplayError msg string begin writeln ERROR msg halt end function GetConnectionString string var s sDSN SUSER sPassword string function GetStringValue sPrompt string string var sValue string begin write sPrompt readin sValue GetStringValue sValue end begin if supported feature_odbc then begin sDSN GetStringValue Enter Data Source Name DSN sUser GetStringValue Enter user id sPassword GetStringValue Enter password s ODBC DSN sDSN user sUsert password sPassword end else if s
47. Description 6 6 5 4 For unpack it is an error if any of the components of the packed array are undefined Simplified Description The unpack procedure transfers all of the elements of the packed array into the unpacked array so it is an error if any of the elements of the packed array are undefined Error Handling This error is never reported 18 32 Invalid use of unpack 3 Official Description 6 6 5 4 For unpack it is an error if the index type of the unpacked array is exceeded Simplified Description In other words it is an error if the unpack procedure attempts to transfer array elements from the packed array into elements of the unpacked array that do not exist For example given var unpacked value array 1 10 of integer packed value packed array 21 30 of integer then unpack packed value unpacked value 2 means that the unpack procedure should attempt to transfer all ten elements from the packed array into the unpacked array starting at element 2 i e transfer elements 21 30 from the packed array into elements 2 11 of the unpacked array but the unpacked array does not have an element 11 Error Handling This error is always reported 18 33 Square of large numbers Official Description 6 6 6 2 Sqr x computes the square of x It is an error if such a value does not exist Simplified Description In other words it is an error if sqr x is too large to be represented by the real type E
48. No 7 2 63 The swap function Description The swap function returns an integer value that is calculated by reversing the order of the bytes in the parameter passed to it In other words this function converts little endian integer values to big endian integer values and vice versa Parameter The swap function s only parameter is an expression of one of the following types byte In this case the swap function will convert the single byte parameter into a four byte integer reverse the order of the four bytes making up this integer and then return the reversed bytes as a value of type integer integer or subrange of integer In this case the swap function will reverse the order of the four bytes making up the parameter and then return the reversed bytes as a value of type integer shortint In this case the swap function will convert the two byte parameter into a four byte integer reverse the order of the four bytes making up this integer and then return the reversed bytes as a value of type integer shortword In this case the swap function will convert the two byte parameter into a four byte integer reverse the order of the four bytes making up this integer and then return the reversed bytes as a value of type integer word or subrange of word In this case the swap function will reverse the order of the four bytes making up the parameter and then return the reversed bytes as a value of type word Notes The s
49. Simplified Description In other words if you have write 100 w or write 100 23 w f it is an error if w or f is less than one Error Handling This error is reported if range checking is enabled 18 60 Problems with program parameters Official Description 6 10 The execution of any action operation defined to operate on a variable is an error if the variable is a program parameter and as a result of the binding of the program parameter the execution cannot be completed as defined Simplified Description In other words it is an error to use a program parameter in a way that is not allowed because of its binding to an external entity Error Handling The bindings of program parameters used by Irie Pascal do not prevent their use in any way and so this error can not occur 18 61 Problems with conformant arrays Official Description 6 6 3 8 For a conformant array it is an error if the smallest or largest value specified by the index type of the actual parameter lies outside the closed interval specified by the index type specification of the conformant array schema Error Handling Irie Pascal does not support conformant arrays so this error can not occur 19 1 I O error codes Description The following trappable error codes may be returned from various operations If automatic error trapping is enabled the default situation then the compiler generates code to automatically check operations for tr
50. The rewinddir procedure 7 4 50 The rewrite procedure 7 4 51 The rmdir procedure 4 52 Th k pr f 7 4 53 The setfiledate procedure 7 4 54 The setfiletime procedure 7 4 55 The sleep procedure 7 4 56 The str procedure 7 4 57 The textbackground procedure 4 58 The textcolor pr 7 4 59 The traperrors procedure 7 4 60 The unpack procedure 7 4 61 The val procedure 7 4 62 The write procedure 7 4 63 The writeln procedure 7 5 User Declared Procedure 7 5 1 Procedure declarations 7 6 External Functions And Procedures 7 6 1 Calling external functions and procedures 8 Expressions 8 1 What are expressions 8 2 Set constructors 8 3 Type Conversion Rules 8 3 1 What are type conversion rules 8 3 2 Numeric type conversion rules 8 3 3 Char String type conversion rules 8 4 Operators 8 4 1 What are operators 8 4 2 Arithmetic Operators 8 4 2 1 The arithmetic operators 8 4 2 2 Addition 8 4 2 3 Unary plus 8 4 2 4 Subtraction 8 4 2 5 Unary minus 8 4 2 6 multiplication 8 4 2 7 Real division 8 4 2 8 Integer division div 8 4 2 9 Modulus mod 8 4 3 Equality Operators 8 4 3 1 The equality operators 8 4 3 2 Is equal 8 4 3 3 Is not equal 8 4 4 Relational Operators 8 4 4 1 The relational operators 8 4 4 2 Is less than 8 4 4 3 Is less than or equal 8 4 4 4 Is greater than 8 4 4 5 Is greater than or equal 8 4 5 Boolean Operators 4 5
51. To Text Files If the file being written to is a text file i e a file associated with a file variable of type text then the write parameters can be made up of the following three items 1 An expression specifying the value to be written to the file NOTE Non string values are converted to string values before being written to the file however the type of the write parameter is the type of the value before it was converted 2 An optional expression of integral type that specifies the minimum width of the string value written to the file If this item is not supplied then the minimum width used depends on the type of the write parameter as follows If the write parameter has an integral type or boolean type then the default minimum width is eigth 8 If the write parameter is of real type then the default minimum width is nine 9 If the write parameter is of string type then the default minimum width is the length of the string If the write parameter is of If the write parameter is of any other type then the default minimum width is one 1 3 An optional expression of integral type that specifies the number of digits that follow the decimal point in the converted string the value is converted into a fixed point representation If this item is not supplied and a value of real type is being converted then the value is converted into an exponential representation NOTE This item only be used when the write parameter is of real_ type
52. WSAEWOULDBLOCK is declared in the system include file WinSock2 inc How To Avoid Getting Blocked There are basically two ways you can ensure that your program will never becoming blocked 1 You can enable non blocking mode for sockets that might otherwise become blocked See the ioctlsocket function for more information 2 You can make sure that the conditions that might cause a socket to block never occur The conditions that might cause a socket to block are e Trying to read data from a socket when there is no data to read 3 Trying to write data to a socket when the trasport system has no space to hold the data 4 Trying to accepting a connection when there are no connection requests waiting to be accepted See the select function for more information 12 9 2 The ioctlsocket function Description The ioctlsocket function sends commands to sockets See the description of the function arguments below for information about the commands that can be sent Declaration The system include file WinSock2 ine contains the following declaration for the ioctlsocket function function ioctlsocket s SOCKET cmd integer var argp u_long integer external dll ws2_32 d11 Arguments The First Argument The first argument passed to the ioctlsocket function is the socket that you want to send a command to The Second Argument The second argument passed to the ioctlsocket function is the command that you want to send
53. a file First it asks for the name of the file Then it assigns the name to a file variable Finally it calls erase on the file variable J RRR KKK Kk kk kkk k kkk k kkk k kkk k kk k k kk k k kk k k kk k k k k k k k k program rm input output var fn filename f binary begin write Which file do you want to delete readin fn assign f fn erase f end Portability Operating Systems Al1 Standard Pascal No 7 4 15 The exec procedure Description The exec procedure executes a command by passing it to the command processor The built in variable exitcode contains the numeric code returned by the command processor to indicate whether an error occured If return value of zero means that no error occured while executing the command and any other return value identifies the particular error that occured The values used by the command processors of different operating system to identify which error occured are not standardized and is not documented here Parameter 1 The first parameter is an expression of string type or char type and is the command to execute 2 The second parameter is an expression of string type or char type and contains the arguments used by the command If no arguments are used by the command then this parameter is an empty string Example J RRR KR RK KKK KKK KK KI KK RK KK KK KK k k kk k k k This program lists all the files ending with pas in the cur
54. a variable or a function result Error Handling This error is reported if range checking is enabled 18 51 Assigning out of range set values Official Description 6 8 2 2 For an assignment statement it is an error if the expression is of a set type whose value is not assignment compatible with the type possessed by the variable Simplified Description In other words it is an error to assign an out of range set value to a variable NOTE The previous error said the variable or function identifier but this one just says a variable The reason why function identifier is not meantioned with this error description is that Standard Pascal does not allow set values to be assigned to function identifiers Irie Pascal does allow set values to be assigned to function identifiers and if range checking is enabled does report assigning out of range set values to function identifiers Error Handling This error is reported if range checking is enabled 18 52 Non matching case index Official Description 6 8 3 5 For a case statement it is an error if none of the case constants is equal to the value of the case index upon entry to the case statement Error Handling This error is always reported NOTE As an extension Irie Pascal supports the otherwise keyword which matches the case index if none of the case constants match the case index So technically in that situation this error is not reported 18 53 For loops in
55. always real NOTE The return type is real instead of one of the integral types because the integral part of the parameter may be too big to fit in any of the integral types and you can always use the built in function trunc to convert the return value from real to integer Parameter The int function s only parameter is the expression of real type whose integral part is to be returned Example int 7 234 returns 7 0 Portability Operating Systems Al1l Standard Pascal No 7 2 26 The ioresult function Description The ioresult function returns the number of the last trappable error that occured Use of this function is no longer recommended new programs should use getlasterror instead Parameter None Portability Operating Systems All Standard Pascal No 7 2 27 The isalpha function Description The isalpha function returns a value of type boolean which indicates whether the parameter passed to it is an alphabetic character If the parameter is an alphabetic character then the value true is returned and if the parameter is not an alphabetic character then the value false is returned Parameter The isalpha function s only parameter is an expression of char type Example isalpha a returns true isalpha A returns true isalpha l returns false isalpha returns false isalpha returns false Portability Operating Systems Al1l Standard Pascal No 7 2 28 The isalphanum func
56. an error message 15 7 Size of real constants The maximum size of a real constant is approximately 1e308 If you exceed this limit the compiler will issue an error message 15 8 Size of code and data The maximum size of the code in a program is 4GB The maximum size of the data in a program is 4GB If you exceed these limits the compiler will issue an error message 15 9 Number of set elements The maximum number of set elements that can be present in a set value is 256 NOTE This limit does not apply to the range of the values of set elements in set values For example in the following program program testset var setvar set of 1 2000 begin setvar 1 1000 2000 writeln l in setvar writeln 1000 in setvar writeln 2000 in setvar end Although the range of values in the set constructor is 2 000 the number of set elements actually present in the set constructor is three so this program runs without a problem 15 10 Nesting of statements Irie Pascal places two limits on the maximum depth to which statements can be nested The first limit is a general limit and limits the maximum depth to which any statement can be nested inside any other statement This limit is 256 NOTE This does not mean that the maximum number of statements in a program is 256 This limits the depth of nesting i e the depth to which statements contain other statements which in turn contain other statements If you exceed thi
57. and can be used on all types of sockets The shutdown function does not close the socket Any resources attached to the socket will not be freed until the closesocket function is called To ensure that all data is sent and received on a connected socket before it is closed your program should use the shutdown function to close the connection before calling the closesocket function to close the socket For example to initiate a graceful disconnect Call the shutdown to disable the transmission of data Call the recv function until zero or SOCKET ERROR is returned Call the closesocket function The shutdown function does not block regardless of the SO_LINGER setting on the socket You should not rely on being able to re use a socket after it has been shut down In particular a Windows Sockets provider is not required to support the use of the connect function on a socket that has been shut down Declaration The system include file WinSock2 ine contains the following declaration for the shutdown function function shutdown s SOCKET how integer integer external dll ws2_32 d11 Arguments The First Argument The first argument passed to the shutdown function is the socket that you want to disable the reception of data from and or disable the transmission of data through The Second Argument The second argument passed to the shutdown function specifies whether you want to disable the receptioin of data the trans
58. and you want to get information about that host then you should do the following 1 Use the inet_addr function to convert the address represented as a string into an actual address in numeric format 2 Use the gethostbyaddr function to get the host information Return Values The gethostbyname function returns a pointer to the hostent structure that contains the host information if the call is successful If the call fails then the value nil is returned and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail Example The following procedure was taken from one of the sample programs distributed with Irie Pascal and shows one way to use the gethostbyname function PURPOSE Given the name of a host performs a DNS lookup PARAMETER s 1 sName contains the name of the host procedure DNSLookUp strName string var pHostEnt p_hostent cstrName cstring begin Convert the name to a cstring since gethostbyname expects a cstring cstrName strName PHostEnt gethostbyname addr cstrName if pHostEnt nil then writeln Can not find host cstrName else DisplayHostEntInfo pHostEnt end The procedure DisplayHostEntInfo is defined by the sample program and displays the host information stored in the hostent structure The procedure DisplayHostEntInfo is below and shows one way to access the host informat
59. array are copied NOTE This parameter must be assignment compatible with the index type of the unpacked array Example Suppose you have the following arrays p packed array 21 23 of integer u array 51 60 of integer then unpack p u 51 copies elements 21 to 23 of p into elements 51 to 53 of u and unpack p u 57 copies elements 21 to 23 of p into elements 57 to 59 of u and unpack p u 59 produces an error since only two elements i e 59 and 60 of u are available to be copied into but all three elements of p must be copied Portability Operating Systems Al1l Standard Pascal Yes 7 4 61 The val procedure Description The val procedure converts a string value into an integral real value and assigns the converted value into a variable Parameters e The first parameter is an expression of string type or char type and is the string value to be converted The second parameter is a reference to a variable of integral type or real type that stores the converted value The third parameter is a reference to a variable of integer type or word type that stores the position of the first conversion error i e the first character in the string value to be converted that could not be converted or zero if there were no conversion errors Example i Given integer variables i and x the following val 123EB i x will store 123 in i and 4 in x Give a real varia
60. arrays A reference to an array variable is a reference to the entire array as a unit and can be used to both store array values into and retreive array values from the array variable The number of values in each array is fixed and each value in the array is identified by a value of the array s index type which is specified when the array is defined Each value in an array is stored in a seperate component of the array called an array element or an indexed variable Each element of an array can be referenced individually in order to store values into and retrieve values from specific elements See the syntax section below for details Example Below are some examples of array variable declarations scores array 1 200 of integer name array IndexType of real students array 1 MAX STUDENTS of student grades array 1 10 of array 1 5 of integer grades array 1 10 1 5 of integer NOTE These examples assume that IndexType is a previously defined ordinal type MAX STUDENTS is a previously defined constant of integral type and student is a previously defined type Also the two declarations shown for the array grades are equivalent Here is a simple example program that generates some random numbers stores them in an array sorts the numbers and then prints the numbers out program sort output const max 20 var numbers array l max of integer procedure GenerateRandomNumbers var i
61. begin writeln message end begin DisplayHello end NOTE There ar two declarations for the procedure display The first declaration for display uses the forward and omits the procedure block but declares the formal parameter message The second declaration for display includes the procedure block which references the formal parameter message even though message is not declared in the second declaration It would be an error or declare the formal parameter in the second declaration of display Syntax The syntax for declaring forward functions and procedures is give below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax function declaration function heading forward directive procedure declaration procedure heading forward directive forward directive forward function heading function identifier formal parameter list result type procedure heading procedure identifier formal parameter list result type type identifier A second declaration for the function or procedure must appear later on in the program with the function or procedure block included but the formal parameter list omitted The syntax for the second declaration of the function or procedure is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax function declaration function identification function block procedure de
62. binary integer 2 8 1 2 Integers Decimal notation Integers in decimal notation i e decimal integers are formed using base 10 with the decimal digits 0 to 9 representing the values zero to nine Example Here are some examples of valid decimal integers 100 0 7453 000005 Syntax decimal integer digit sequenc digit sequence digit digit digit 0 1 2 3 4 5 6 7 8 9 2 8 1 3 Integers Hexadecimal notation Integers in hexadecimal notation i e hexadecimal integers are formed using base 16 with the decimal digits 0 to 9 representing the values zero to nine and the letters A to F representing the values ten to fifteen Integers in hexadecimal notation are prefixed with the symbol Example Here are some examples of valid hexadecimal integers 64 0 SEF 000aB4 Syntax The syntax for hexadecimal integers is as follows hexadecimal integer hex digit sequenc hex digit sequence hex digit hex digit hex digit digit a b c d e digit 0 1 2 3 4 5 6 7 8 9 2 8 1 4 Integers Binary notation Integers in binary notation i e binary integers are formed using base 2 with the decimal digits 0 and 1 representing the values zero and one Integers in binary notation are prefixed with the symbol Example Here are some examples of valid binary integers 01100110 0 11111111 Syntax binary integer binary digit sequenc
63. blocking for more information about the non blocking mode of sockets Non blocking mode disabled If the socket has it s non blocking mode disabled and there is no buffer space available within the transport system to store the data to be transmitted then the send function will block and wait for buffer space to become available or for the connection to be closed connection oriented sockets only or for the connection to be reset connection oriented sockets only Non blocking mode enabled If the socket has it s non blocking mode enabled then the number of bytes actually sent can be less than the amount you are trying to send depending the availability of buffer space within the transport system to store the data to be transmitted If there is no buffer space available within the transport system to store the data to be transmitted then the send function will fail and return SOCKET ERROR and if you then call the WSAGetLastError function to find out the reason for the failure the error code returned will be WSAEWOULDBLOCK You can use the select function to find out when some buffer space becomes available NOTE The constants WSAEWOULDBLOCK and SOCKET ERROR are declared in the system include file WinSock2 inc Connectionless Sockets When the send function is used on connectionless sockets care must be taken not to exceed the maximum packet size of the underlying provider which can be obtained by using getsockopt to retrieve
64. body end case index ordinal expression case body case list elements case statement completer case statement completer case list elements case list element case list element case list element case constant list statement case constant list case specifier case specifier case specifier case constant case constant case constant ordinal constant case statement completer otherwise else statement sequenc 9 9 Repeat statement Description Repeat statements perform an action in a conditional loop until the loop condition is true and include the following A statement sequence that specifies the action performed in the loop If a statement in the statement sequence transfers program execution to a statement outside of the repeat statement then execution of the repeat statement is terminated when program execution is transfered The loop condition which is specified by an expression of boolean type After each iteration of the loop the loop condition is evaluated and if it s value is false the loop continues but if it s value is true the loop terminates NOTE The loop condition is evaluated after the statement sequence is executed so the statement sequence is executed at least once Usually the statement sequence will perform some action that will eventually cause the loop condition to be true and terminate t
65. buffer variable Simplified Description In other words it is an error to write a value to a file if the value is not assignment compatible with the file type s component type Or to put it another way it is an error to write a value to a file if the value is not a valid value for that file For example given type positive 0 maxint var f file of positive then write f 1 is an error since 1 is not assignment compatible with 0 maxint Error Handling This error is reported if range checking is enabled 18 20 new p cl cN constraints violated Official Description 6 6 5 3 For new p cl cN it is an error if a variant of a variant part within the new variable becomes active and a different variant of the variant part is one of the specified variants Simplified Description In other words if you use this form of the new procedure and specify case constants c1 thru cN then it is an error if a variant other than those specified by c1 thru cN become active Error Handling Irie Pascal does not support this form of the new procedure so this error can not occur 18 21 Incompatible use of dispose p Official Description 6 6 5 3 For dispose p it is an error if the identifying value had been created using the form new p c1 cN Error Handling Irie Pascal does not support this form of the new procedure so this error can not occur 18 22 Incompatible use of dispose p k1 kM Official Description
66. by this procedure may be less than the maximum number of characters specified if there is an I O error you can check this by disabling I O checking and using the getlasterror function or if the end of file is reached Parameter 1 The first parameter is a reference to the file variable associated with the file to read 2 The second parameter is a reference to the character buffer used to store the characers read from the file The character buffer must be a variable of type string or a packed array of type char 3 The third parameter is an expression of integral type which specifies the maximum number of characters to read from the file 4 The fourth parameter is a reference to a variable of type integer or type word which will contain the actual number of characters read from the file Example The simple program below copies the contents of an input file into an output file It is similar to the UNIX program cat The program uses the built in procedures rawread and rawwrite to perform the T O program cat f g const max 400 var f g text buffer packed array 1l max of char actual integer begin reset f rewrite g while not eof f do begin rawread f buffer max actual if actual lt gt 0 then rawwrite g buffer actual actual end close g close f end Portability Operating Systems Al1l Standard Pascal No 7 4 43 The rawwrite procedure Descrip
67. choice of action Case list elements contain one or more case constants and a statement The case constants in a case list element specify values which if equal to the value of the case index will cause that case list element to be choosen The statement in a case list element specifies the action performed when that case list element is choosen This statement can be a compound statement containing a statement sequence If this statement transfers program execution to a statement outside of the case statement then execution of the case statement is terminated when program execution is transfered e Asan extension to Standard Pascal Irie Pascal allows case statements to include case statement completers which if present represents a kind of default choice of action i e the action choosen when none of the other actions are choosen Case statement completers contain a statement sequence which specifies the action performed when the case statement completer is choosen If one of the statements in the statement sequence transfers program execution to a statement outside of the case statement then execution of the case statement is terminated when program execution is transfered Constant ranges can be used to specify a number of contiguous case constants for example 1 5 is the same as 1 2 3 4 5 No two case list elements can contain the same constant so case x of 1 2 3 2 wette 1 to 3 2 write 2 end is an err
68. closesocket function closes a socket and frees the resources attached to the socket To assure that all data is sent and received on a connection your program should call the shutdown function before calling the closesocket function NOTE An FD_CLOSE network event is not posted after the closesocket function is called Your program should always have a matching call to the closesocket function for each successful call to the createsocket function to return any socket resources to the system The behavior of the closesocket function can be affected by the socket options SO_LINGER and SO_DONTLINGER When a socket is created SO_DONTLINGER is enabled and therefore SO_LINGER is disabled SO_LINGER Enabled If the SO_LINGER socket option is enabled with a zero time out interval that is the inger structure members onoffis not zero and linger is zero the closesocket function will not block even if queued data has not yet been sent or acknowledged This is called a hard or abortive close because the connection is reset immediately and any unsent data is lost Any recy function call on the remote side of the connection will fail and the WSAGetLastError function with return WSAECONNRESET If the SO_LINGER socket option is set with a nonzero time out interval on a socket with it s non blocking mode disabled the closesocket function will block until any remaining data has been sent or until the time out expires This is called a graceful discon
69. conditions that must be true if your program has no bugs A common mistake is using the assert procedure to test normal error conditions that may happen even if your program is bug free such as out of memory conditions or invalid user input For normal error conditions it is usually better to check for these in some other way and handle them in a more graceful way Parameters The assert procedure s only parameter is an expression of boolean type Portability Operating Systems Al1l Standard Pascal No 7 4 4 The assign procedure Description The assign procedure names a file variable NOTE You can t use this function to rename a file use the built in procedure rename if you want to do that Parameters 1 The first parameter is a reference to the file variable to be named 2 The second parameter is an expression of string type or char type and is the new name of the file variable The name of a file variable controls which file is opened when the file variable is opened If the name is a non empty string then a file with that name is opened If the name is an empty string then the file opened is either the standard output file or a temporary file with a system generated name depending on the project options set when the program was compiled Example For example to open a file named README TXT for reading you could use assign f README TXT reset f where f is a reference to a file variable
70. connection object containing an open connection to a database sSQL is a string variable containing the SQL statement that defines the recordset rsdynamic specifies that a dynamic recordset should be opened Portability Operating Systems All Standard Pascal No 4 2 46 rsforward Description rsforward is used when opening a recordset see recordset open to specify that a forward only recordset should be opened Forward only recordsets as the name suggests only allow you to move forwards To return to previous record your program would have to close the recordset reopen it and skip to the record you are interested in Database changes i e record insertions updates or deletions are not visible to forward only recordsets after the recordset is opened Example rs open conn sSQh rsforward In the example above rs is the recordset object that will contain the opened recordset conn is the connection object containing an open connection to a database sSQL is a string variable containing the SQL statement that defines the recordset rsforward specifies that a forward only recordset should be opened Portability Operating Systems Al1l Standard Pascal No 4 2 47 rskeyset Description rskeyset is used when opening a recordset see recordset open to specify that a keyset recordset should be opened Keyset recordsets are scrollable i e you can move both forwards and backwards through the records in the recordset Some
71. copy of ISO IEC 7185 Finally a statement describing how Irie Pascal treats the feature is at the end Effect of writing prohibited characters Order of evaluation of index expressions Order of evaluation of expressions of a member designator Order of evaluation of member designators Order of evaluation of operands of dyadic operators Order of evaluation of actual parameters for function calls Order of evaluating components of assignment statements Order of evaluation of actual parameters for procedure calls Effect of reading a text file to which page has been applied Binding of non file program parameters 17 2 Effect of writing prohibited characters 6 4 3 5 For any text file t the effect of attributing to a component of either t L or t R a member of the characters prohibited from text files is implementation dependent In other words the effect of writing any of the characters that implementations are allowed to prohibit from text files to a text file is implementation dependent Irie Pascal prohibits one character from text files the character is chr 26 the end of file character Writing the end of file character to a text file causes the file to be terminated i e the EOF character and any characters written after the EOF character will not appear when the file is read 17 3 Order of evaluation of index expressions 6 5 3 2 The order of evaluation of the index expressions of an indexed variable is implemen
72. featur tbackground then textbackground blue if supported feature tcolor then textcolor white writeln white on blue end x Portability Operating Systems Al1l Standard Pascal No 4 2 21 feature_textcolor textcolor supported Description feature_textcolor can be used to determine if the current platform supports the built in procedure textcolor Example program color output const blue 1 white 15 begin if supported featur xtbackground then textbackground blue if supported feature textcolor then textcolor white writeln white on blue end Portability Operating Systems Al1l Standard Pascal No 4 2 22 feature_wherex wherex supported Description feature_wherex can be used to determine if the current platform supports the built in function wherex Example if supported feature _wherex then xpos wherex if supported feature wherey then ypos wherey Portability Operating Systems Al1l Standard Pascal No 4 2 23 feature_wherey wherey supported Description feature_wherey can be used to determine if the current platform supports the built in function wherey Example if supported feature _wherex then xpos wherex if supported feature_ wherey then ypos wherey Portability Operating Systems Al1l Standard Pascal No 4 2 24 grp r Description grp_r can be AND d se
73. file is opened but the file buffer is empty put the contents of the file buffer are appended to the file reset the file is opened but the file buffer is not filled until it is accessed get If the file buffer is full then the file buffer is emptied to make room for the next file value NOTE In this case no I O is actually performed If the file buffer is empty then the next data value is skipped i e read and ignored The file buffer remains empty 16 9 Value of maxint 6 7 2 2 The required constant identifier maxint shall denote an implementation defined value of integer type Irie Pascal uses 2 147 483 647 as the value of maxint 16 10 Accuracy of real operations and functions 6 7 2 2 The accuracy of the approximation of the result of the real operations and functions to the mathematical result is implementation defined Irie Pascal performs real operations as specified in IEEE standard for binary floating point arithmetic ANSI IEC std 754 1985 and the final results are stored in 64 bit reals 16 11 Default value of TotalWidth for integer type 6 9 3 1 The default value of TotalWidth for integer type is implementation defined In other words when writing integer values to text files the default width of the output field is implementation defined Irie Pascal uses 8 as the default value of TotalWidth for integer type So for example write one 1 will cause one 1 to be written i e the integer
74. function FileExists name filename boolean var f text begin traperrors false reset f name FileExists getlasterror 0 if FileExists then close f traperrors true end begin writel n Enter filename readin n writel end trim n n n Does 1T EES n exist Portability Operating Systems Al1l Standard Pascal No Qel foo FileExists n ff terminating procedure an error 7 4 60 The unpack procedure Description The unpack procedure assigns values to some or all of the elements of an unpacked array by copying all of the elements of a packed array into the unpacked array The elements of both arrays must have the same type Parameter e The first parameter is a reference to the packed array variable that contains the array elements to copy The second parameter is a reference to the unpacked array variable that contains the array elements to be copied into The third parameter is an expression of ordinal type that specifies the start element of the unpacked array 1 e the element of the unpacked array to start copying to All of the elements of the unpacked array from the start element to the end are available to be copied into It is an error if the number of elements in the unpacked array available to be copied into is less then the number of elements in the packed array since all the elements in the packed
75. i e the address of the identified variable in the pointer variable Initializes a list variable before it is used Creates an instance variable from an object variable and stores the value referencing the instance variable i e the address of the instance variable in the object variable Parameter The new procedure s only parameter is a reference to a pointer variable object variable or object variable Portability Operating Systems A1l1 Standard Pascal Yes Standard Pascal does not support the list type or the object type and so does not support using the new procecedure on variables of those types 7 4 35 The open procedure Description The open procedure associates a file variable with a file i e opens the file variable and allows it to be used to manipulate the file The open procedure can open the file variable in read only mode write only mode read write mode or append mode Parameters 1 The first parameter is a reference to the file variable to be opened 2 The second parameter is an expression of string type or char type and names the file variable referenced by the first parameter as if the built in procedure assign had been called 3 The third parameter is an expression of integral type which specifies the mode the file variable should be opened in The file mode constants can be used to specify the mode The readmode and writemode constants can be added or OR d together to specify tha
76. if the control variable is passed as an actual parameter to these procedures A for statement threatens it s own control variable Example The following program uses a for statement to count from 1 to 10 program CountToTen output procedure CountToTen var L Deel Oy begin CountToTen for i 1 to 10 do writeln i end CountToTen begin CountToTen end Syntax NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax for statement do statement for control variable initial value to downto final value control variable entire variable initial value ordinal expression final value ordinal expression 9 12 With statement Description With statements perform an action while allowing the fields of specified record variables to be referencing using their field identifiers only With statements include the following A record variable list which contains one or more record variables A statement which specifies the action to perform Inside this statement the fields in any of the record variables in the record variable list can be referenced using their field identifiers only Example For example give the following type and variable type student record name string address string grade integer end var s student then the following with statement with s do begin name John
77. integer value 5 Operator Categories Operators can be grouped into the following categories Arithmetic operators Equality operators Relational operators Boolean operators String operators Set operators Bitwise operators 8 4 2 1 The arithmetic operators The arithmetic operators are Addition Unary plus Subtraction Unary minus Multiplication Real division integer division div Modulus mod 8 4 2 2 Addition Description When the operator has two operands of integral type or real type it performs addition according to the following rules First the numeric type conversion rules are applied After applying the numeric type conversion rules the operands are either both of integer type or both of word type or both of real type or one operand is of address type and the other operand is not If both operands are of integer type then unsigned integer addition is performed and the result is a value of type integer If both operands are of word type then unsigned integer addition is performed and the result is a value of type word e If both operands are of real type then real i e floating point addition is performed and the result is a value of type real If one operand is of address type and the other operand is not then unsigned integer addition is performed and the result is a value of address type Example Here are some examples using the operator to perform addi
78. list file variable variable access variable access write parameter expression expression expression write parameter list file variable write parameter write parameter writeln parameter list file variable write parameter write parameter 9 5 Goto statement Description Goto statements unconditionally transfer program execution to the statement prefixed by a label Execution of a goto statement is terminated when it transfers program execution If a goto statement transfers program execution to a statement outside of the current block then the call stack is unwound i e functions and procedure calls are terminated until the block containing the statement referred to by the goto statement is reached So for example if the main program calls a procedure A and procedure A calls procedure B and procedure B calls procedure C and a goto statement in procedure C transfers program execution back to a statement in procedure A then procedures C and B are terminated Standard Pascal ISO IEC 7185 describes the rules governing the use of goto statement as follows A label if any of a statement S shall be designated as prefixing S The label shall be permitted to occur in a goto statement G if and only if any of the following three conditions is satisfied a S contains G b S is a statement of a statement sequence containing G c S is a statement
79. memory address If the variable is not of address type or of pointer type then the address of the variable itself is the destination memory address 3 The third parameter is an expression of integral type which specifies the number of memory locations to copy NOTE This parameter is always treated as an unsigned integer number Portability Operating Systems Al1l Standard Pascal No 7 4 33 The msdos procedure Description The msdos procedure makes a call to MSDOS through x86 processor interrupt 21 Parameter The msdos procedure s only parameter is a reference to the variable of registers type which contains values to pass into the x86 processor registers before the interrupt is generated and which receives the contents of the x86 processor registers after the interrupt is serviced Example For example the following simple program uses MSDOS function 30 to get the MSDOS version number program GetVer output var regs registers begin fill regs 0 regs ah 30 regs al 00 msdos regs write MSDOS version is if regs al 0 then writeln 1 else writeln regs al 1 regs ah 1 end Portability Operating Systems DOS Only Standard Pascal No 7 4 34 The new procedure Description The new procedure performs the following actions Creates an identified variable from a pointer variable and stores the value identifying the identified variable
80. n o p q r s t u ll v w x y z y y list type list of component type list variable variable access max string length integral constant integral constant member designator ordinal expression ordinal expression multiplying operator div mod and and_then name string literal new ordinal type enumerated type subrange type new pointer type domain type domain type new structured type packed array type packed record type packed set type packed file type packed list type object type string type new type new ordinal type new structured type new pointer type non empty string string element one string element one string element one string element two string element two string element two object type object class object variable variable access ordinal constant constant ordinal expression expression ordinal type new ordinal type ordinal type identifier ordinal type identifier identifier pascal st point tring type string max string length ter variable variable access printable character any character including a space that representation procedure block block has a visual procedure declaration procedure heading directive procedur
81. of ordinal type is not assignment compatible with the index type of the unpacked array parameter Simplified Description In other words the parameter used to specify the first element of the unpacked array to transfer to the packed array must be assignment compatible with the index type of the unpacked array Or to put it another way the first element of the unpacked array to transfer to the packed array must exist For example given var unpacked value array 1 10 of integer packed value packed array 21 30 of integer then pack unpacked value 0 packed value is an error since 0 is not assignment compatible with 1 10 Or to put it another way element 0 of the unpacked array does not exist Error Handling This error is always reported 18 28 Invalid use of pack 2 Official Description 6 6 5 4 For pack it is an error if any of the components of the unpacked array are both undefined and accessed Simplified Description In other words it is an error if the pack procedure attempts to transfer undefined array elements from the unpacked array Error Handling This error is never reported 18 29 Invalid use of pack 3 Official Description 6 6 5 4 For pack it is an error if the index type of the unpacked array is exceeded Simplified Description In other words it is an error if the pack procedure attempts to transfer array elements from the unpacked array that do not exist For example given
82. of the interpreter running the program The version number returned by this function is constructed of four bytes in little endian format as follows 1 The first byte contains the least significant verion number and is changed when very minor changes are made to the interpreter e g minor bug fixes 2 The second byte contains the minor version number and is changed when significant changes are made to the interpreter e g support for new features are added 3 The third byte contains the major version number and is changed when major changes are made to interpreter e g the format of executable is changed 4 The fourth byte is currently undefined and always contains zero The type of the value returned by this function is always integer The version number returned by this function is not related to the version of the Irie Pascal compiler or the version of the operating system Currently you will probably not need to use this function however this function is provided because each new version of the interpreter is likely to add support for new features Therefore programs in the future may need to know which version of the interpreter they are running on to determine whether a particular feature is available see the supported function for a better way to do this Parameter None Example version currently returns the following bytes 00 05 02 00 So the major version number is five the minor version number is two and
83. of the statement sequence of the compound statement of the statement part of a block containing G To fully understand these rules you will probably need a copy of the Standard ISO IEC 7185 but the following explanation should suffice for most people The first two rules cover goto statements that refer to statements in the current block while the last rule covers goto statements that refer to statements in an enclosing block The rules are basically saying that you can t use a goto statement to jump into the middle of a statement from outside of that statement So for example the following code fragment is illegal goto 1 for i 1 to 10 do 1 writeln i Example Below is a simple program illustrating how to use goto statements program ten output label loop var count integer begin count 1 loop writeln count count count 1 if count lt 10 then goto loop end NOTE The label loop used in this program is declared before it is used which is a requirement for all labels Syntax NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax goto statement goto label 9 6 Compound statement Description Compound statements group a statement sequence i e one or more statements into a single statement and are executed as follows Program execution is transfered to the first statement in the statement sequence Program execution
84. or procedure blocks this means that these variables will be created when the function or procedure is activated and destroyed when the function or procedure is terminated Named variables are referenced simply by using their names i e the identifiers associated with the variables Example For example below is a simple program that introduces an integer variable associates the variable identifier n with the new variable stores 100 in the the variable retrieves the value stored in the variable and displays the value on the screen program number output var n integer declare variable n of type integer begin n 100 Store 100 in the variable writeln n Retrieve the value in the variable and display it on the screen end 6 3 Anonymous variables Description Anonymous variables are not associated with identifiers Anonymous variables can be grouped into the following four sub categories 1 Buffer variables 2 Identified variables see pointer variables 3 Instance variables see object variables 4 Selected variables see list variables 6 4 Array variables Description Array variables are used to store values of array types i e collections of values of the same type The type of each value in an array is called the array s component type An array s component type may be any type including an array type so it is possible to define arrays of arrays also called multi dimensional
85. packed record l_onoff u_short 1_linger u_short end function closesocket s SOCKET integer external dll ws2_32 d11 Arguments The First Argument The first and only argument passed to the closesocket function is the socket that you want to close Return Values The closesocket function returns a value of integer type that indicates whether the call was successful A value of zero means that the call succeeded A value of SOCKET ERROR indicates that the called failed and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail NOTE The constants SO_LINGER SO_DONTLINGER WSAECONNRESET WSAEWOULDBLOCK SOCKET ERROR and the type linger are declared in the system include file WinSock2 inc Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 16 1 The gethostname function Description The gethostname function retrieves the host name of the local computer This host name can be a simple host name or a fully qualified domain name but whatever it s form the host name retrieved is guaranteed to be successfully parsed by the gethostbyname function This is true even if no host name has been configured for the local computer Declaration The system include file WinSock2 ine contains the following
86. performs a single action 1 e the action specified by the then part When this if statement is executed the if condition i e x y is evaluated and if true the statement in the then part i e writeln x is equal to y is executed and if false then execution of the if statement is terminated Here is another example if x y then writeln x is equal to y else writeln x is not to y is an if statement that performs one of two actions i e either the action specified by the then part or the action specified by the else part When this if statement is executed the if condition i e x y is evaluated and if the value of the test condition is true then the statement in the then part i e writeln x is equal to y is executed and if the value of the test condition is false then the statement in the else part i e writeln x is not equal to y is execuited Syntax NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax if statement if boolean expression then statement else part else part else statement 9 8 Case statement Description Case statements perform one action out of a choice of actions and include the following A case index which is specified by an ordinal expression i e an expression of ordinal type The case index is evaluated and it s value determines which action is performed Zero or more case list elements each of which represent a
87. program Portability Operating Systems Al1l Standard Pascal No 7 4 28 The inc procedure Description The ine procedure increments the value stored in a variable Parameter 1 The first parameter is a reference to the variable of ordinal type whose value is to be incremented 2 The second parameter is an expression of integral type and is the value by which the variable is to be incremented If this parameter is not supplied then the variable is incremented by one Example inc x decrements the variable x by 1 inc x 10 decrements the variable x by 10 Portability Operating Systems Al1l Standard Pascal No 7 4 29 The insert procedure Description The insert procedure either inserts a string into another string or inserts a value into a list Parameter 1 The first parameter is an expression whose value is to be inserted into the string or list 2 The second parameter is a reference to the string variable or the list variable into which the value is to be inserted 3 The third parameter is an expression of integral type and is the position in the string or list where the value is to be inserted If this parameter is not supplied then the value is inserted at the end of the string or list Example Here are some examples using the insert procedure with strings Assuming that x is a string variable then after x ABC insert DEF x insert DEF at the end of x
88. readonly is a read only property of type boolean Example For example if conn is a connection object reference with an open connection to a database engine then the following conn readonly indicates whether or not the connection referenced by conn is read only Portability Operating Systems Al1l Standard Pascal No 5 15 20 13 connection transactions Description The transactions property of the connection object type indicates connection object type indicates whether or not transactions are supported by the database engine connected to NOTE transactions is a read only property of type boolean Example For example if conn is a connection object reference with an open connection to a database engine then the following conn transactions indicates whether transactions are supported by the database engine Portability Operating Systems Al1l Standard Pascal No 5 15 20 14 connection transsupport Description The transsupport property of the connection object type indicates the level of transaction support provided by the database engine connected to NOTE transsupport is a read only property of type integer Example For example if conn is a connection object reference with an open connection to a database engine then the following conn transsupport contains the level of transaction support provided by the database engine The possible values of this property are sql tc none Transaction
89. returned will be WSAECONNRESET NOTE The constants VWSAECONNRESET and SOCKET ERROR are declared in the system include file WinSock2 inc Connectionless Sockets When the reevfrom function is used on connectionless sockets it will read the first datagram waiting to be read If the first datagram waiting to be read is larger than the buffer you supply then only the first part of the datagram will be read enough to fill the buffer and the reevfrom function call will return SOCKET ERROR as if the call failed and if you then call the WSAGetLastError function the error code returned will be WSAEMSGSIZE For unreliable protocols for example UDP the unread part of the datagram will be lost For reliable protocols the entire datagram is retained until it is successfully read by calling the recvfrom function with a large enough buffer The name of the socket that sent the data is retrieved if you supply a buffer to store the name see the fifth and sixth arguments below Declaration The system include file WinSock2 ine contains the following declaration for the reevfrom function function recvfrom s SOCKET buf address len flags integer from address var fromlen integer integer external dll ws2_32 d11 Arguments The First Argument The first argument passed to the reevfrom function is the socket that you want to read data from The Second Argument The second argument passed to the recvfrom function is the o
90. returns false isxdigit returns false Portability Operating Systems Al1l Standard Pascal No 7 2 36 The keypressed function Description The keypressed function returns a value of type boolean which indicates whether there are keys in the keyboard buffer waiting to be read If there are keys in the keyboard buffer then the value true is returned and if there are no keys in the keyboard buffer then the value false is returned Parameter None Portability Operating Systems Windows Standard Pascal No 7 2 37 The length function Description The length function returns the number of characters in a string or character or the number of values in a list The type of the value returned by this function is always integer Parameter The length function s only parameter is an expression of one of the following types string type The length function returns the number of characters in the string char type The length function returns one list type The length function returns the number of values in the list Example length returns 0 length a returns 1 length hello returns 5 And if 1 is a list of integer then new 1 length 1l returns 0 and new 1 insert 1 insert 78 insert 45 insert 3 length 1 returns 4 Portability Operating Systems Al1l Standard Pascal No 7 2 38 The In function Description The In function returns the na
91. s contents are deleted If the file does not already exist when the file variable is opened then it is created and is initially empty The mode in which a file variable is opened specifies which operations can be performed on the file associated with the file variable and also what happens to the file when the file variable is opened If a file variable is opened in append mode then operations on the file associated with the file variable are allowed as follow Values can not be retrieved from the file The values in the file can not be changed New values can be added to the file Also if the file already exists when the file variable is opened then it s contents are preserved and the current file position is set to the end of the file If the file does not already exist when the file variable is opened then it is created and is initially empty A file s modification date is the date the file was last modified A file s modification time is the time the file was last modified What are write parameters Description Write parameters are used with the write and writeln procedures to specify the values that these procedures should write to files Writing To Non Text Files If the file being written to is not a text file i e not a file associated with a file variable of type text then the write parameters are just expressions and the values of these expressions are written without conversion to the file Writing
92. server If mysql host parameter is not specified or if host name is an empty string or local host then the connection is opened to the local MySQL server over a UNIX socket The mysql user parameter specifies the username used to connect to the MySQL database server If the mysql user parameter is not specified or if user name is an empty string then the UNIX login name of the person running the program is used The mysql password parameter specifies the password of the user who will be connected to the database server If the mysql password parameter is not specified or if password is an empty string then the connection is rejected if the user actually has a password The mysql database parameter specifies the initial database selected when the connection is opened If the mysql database parameter is not specified or if database is an empty string then no initial database is selected In which case you must call the connection selectdatabase method later on to select a database The mysql port parameter specifies the port used to remotely connect to a MySQL database server over TCP If the mysql port parameter is not specified or if port number is 0 then the default port is used The mysql socket parameter specifies the filename of the UNIX socket used to connect to a MySQL database server on the local machine If the mysqlI socket parameter is not specified or if socket is an empty string then the default socket is used The mysql compr
93. some examples of valid record types record end The record type above is empty record name string grade integer end The record type above has two fields The first field is identified by the field identifier name and this field is of type string The second field is identified by the field identifier grade and this field is of type integer Given the type below type clothes shoe pants shirt the following record type is valid record price real case kind clothes of shoe size integer pants waist length integer shirt neck integer sleeve integer end and contain seven fields price kind size waist length neck and sleeve The fields price and kind are always present and the value of the field kind determine which of the variants if any is present The variants are size integer which is active when kind equals shoe waist length integer which is active when kind equals pants neck integer sleeve integer which is active when kind equals shirt Syntax The syntax for defining new record types is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax record type record field list end case constant ordinal constant case constant list case specifier case specifier case specifier case constant case constant domain typ typ
94. spelling i e differ only in case Example For example consider the code fragment below type STUDENT record name string address string grade integer end var student STUDENT The use of the same spelling for the variable student and its type STUDENT emphasize the connection between the two You should use this compiler option with caution or not at all since this feature of Irie Pascal is not supported by many if any other Pascal compilers Syntax identifier letter letter digit letter a b k l m j n u v w x tot SSE hg eee era Page T tS H TEn Koa N d A digit o TI T2 737 TA EST t 6Et 7E 182 T9 2 9 2 Built in identifiers Built in identifiers are automatically declared by the compiler Unlike reserved words you can declare your own identifiers with the same spelling as built in identifiers if you do then your declaration will override the declaration made by the compiler So for example the following declaration type boolean no yes will override the declaration created by the compiler type boolean false true Some built in identifiers are used by extensions to Standard Pascal and are therefore only declared by the compiler when the extensions are enabled 2 9 3 User defined declared identifiers User defined identifiers are created by the following declarations and definitions Constant definitions Type definit
95. string type cstring max string length max string length integral constant J integral constant pascal string type string max string length where max string length is between and 1048576 and specifies the maximum length of the string If max string length is not specified the default maximum length i e 255 is used 5 12 Subrange types Description Subrange types define a contiguous subset of the values of an ordinal type This ordinal type is known as the subrange type s host type and the values of a subrange type have the same type as its host type Example Here are some examples of subrange types 100 100 true true Wat 4 get Syntax The syntax for defining new subrange types is give below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax subrange type constant constant 5 13 Variant Types Description The variant type is a special type that can contain values of the following types boolean byte integer real E E EE E un a l E word The variant type is the type of the field property of recordset objects and is only used when accessing values from recordset fields which can have a variety of types Variant values are automatically converted to appropriate types whenever they are used in expressions So you can t use this type to declare variables or parameters The idea behind the variant ty
96. supports calling the built in procedure intr Example if not supported feature_intr then begin writeln x86 interrupts not supported on the current platform abort end Portability Operating Systems Al1l Standard Pascal No 4 2 12 feature_keypressed keypressed supported Description feature_keypressed can be used to determine if the current platform supports calling the built in function keypressed Example if not supported feature keypressed then begin writeln keypressed not supported on the current platform abort end Portability Operating Systems Al1l Standard Pascal No 4 2 13 feature_mysql MySQL databases supported Description feature_mysql This constant can be used to determine if the current platform supports using MySQL databases Example program Data input output var conn connection procedure DisplayError msg string begin writeln ERROR msg halt end function GetConnectionString string var S SDSN sUSER sPassword string function GetStringValue sPrompt string string var sValue string begin write sPrompt readin sValue GetStringValue sValue end begin if supported feature_ odbc then begin sDSN GetStringValue Enter Data Source Name DSN sUser GetStringValue Enter user id sPassword GetStringValue Enter password s ODBC
97. tc_dml Description If the transsupport property of a connection type object is equal to this constant i e sql_te_dml then the connection supports transactions which can contain DML data management statements DDL data definition statements in the transactions cause an error Portability Operating Systems All Standard Pascal No 4 2 53 sql_tc_ none Description If the transsupport property of a connection type object is equal to this constant i e sql_te_none then the connection does not support transactions Portability Operating Systems Al1l Standard Pascal No 4 2 54 true Description true is the second enumerated constant defined by the built in enumerated type boolean The ordinal value of true is one Portability Operating Systems Al1l Standard Pascal Yes 4 2 55 usr_r Description usr_r can be AND d see and operator bitwise with the filemode retrieved by the built in procedure getfilemode to determine whether the owner of a file or directory folder has permission to read from the file or directory folder Example For example the simple program below asks for a filename and then displays the file permissions for the owner of the file program OwnerPermissions input output var s filename mode integer isdir boolean begin write Enter filename readln s s fexpand s getfilemode s mode isdir mode and dir bit lt gt
98. the right operand is not evaluated because the result of the operation must be false Example false and_then false results in false false and then tru results in false true and then false results in false true and_then tru results in true The differences between the and_then operator and the and operator are The and_then operator can not be used to perform bitwise AND Short circuit evaluation is always used when by the and_then operator but can be enabled disabled for the and operator 8 4 5 5 or boolean Description When the or operator has operands of boolean type then it performs boolean OR The result of the operation is of boolean type and is equal to true if either operand is true and false if both operands are false By default short circuit evaluation is used when performing the boolean OR i e The left operand is evaluated first and if it is true then the right operand is not evaluated because the result of the operation must be true A compiler option can be used to enable disable short circuit evaluation Example false or false results in false false or true results in true true or false results in true true or true results in true 8 4 5 6 or_else boolean Description As an extension to Standard Pascal Irie Pascal supports the or_else operator which takes two operands of boolean type and performs boolean OR The result of the operation is of boole
99. the length of V must not be greater then the maximum length of T1 Pes ah Assignment compatibility is used to control where and how values can be used in the following situations e Assignment compatibility with array indexing e Assignnment compatibility with value parameter Assignment compatibility with read o e Assignment compatibility with assignment statements Assignment compatibility with for statement Assignment compatibility with transfer pr 10 2 2 Assignment compatibility with array indexing When an element of an array variable is being referenced the value of the index expression shall be assignment compatible with the index type of the array variable For example given var x array 1 10 of integer x i 20 then i the value of the index expression shall be assignment compatible with 1 10 the index type of the array variable 10 2 3 Assignnment compatibility with value parameters When passing an actual parameter by value to a formal parameter of a function or procedure the actual parameter shall be assignment compatible with the type of the formal parameter For example given function IsDigit c char Boolean begin if c in 0 9 then IsDigit true else IsDigit false end and while not IsDigit key do read key then key the actual parameter in IsDigit key shall be assignment compatible with char the type of the formal parameter
100. the parameter is minus 1 i e 1 then the name of the interpreter is returned unless the program is an EXE executable in which case an empty string is returned Example For example the following is a simple program args2 pas that uses the paramstr and paramcount functions to display all of the arguments passed to it program args2 output var i integer begin for i 1 to paramcount do writeln Program argument i 1 is paramstr i end If you run this program as as follow ivm args2 this is a test then the program will display Program argument 1 is ivm Program argument 0 is args2 Program argument 1 is this Program argument 2 is is Program argument 3 is a Program argument 4 is test Portability Operating Systems Al1l Standard Pascal No 7 2 46 The pi function Description The pi function returns the value of the mathematical constant pi The type of the value returned by this function is always real Parameter None Example So for example writeln pi displays 3 14E 00 Portability Operating Systems Al1l Standard Pascal No 7 2 47 The platform function Description The platform function returns a value that indicates the operating system platform that the program is running on NOTE Actually the value returned by this function indicates the edition of Irie Pascal that is executing the program The type of th
101. used to store values of object types each of which either identifies an instance of an object described by the object type or is the built in constant nil which is guaranteed not to reference any instance of an object Currently the only supported object types are the built in object types connection and recordset and the generic object type Object instances are called instance variables and are described in more detail in the next section Instance Variables Instance variables contain the function and procedure methods and properties defined by their object type Function and procedure methods define the operations that can be perfomed on and by instance variables and can be called anywhere a normal function or procedure can be called Properties define the data or at least the visible data contained in the instance variables and be referenced anywhere normal variables can be referenced In the case of object variables of the built in object types connection and recordset instance variables are created by calling the built in procedure new and passing the object variable as a parameter In the case of object variables of the generic object type instance variables are created by calling the built in function createobject and passing the name of a COM object as a parameter In all cases instance variables are destroyed by calling the built in procedure dispose and passing the object variable that was used to create the i
102. value to be returned by the program or function or procedure Portability Operating Systems Al1l Standard Pascal No 7 4 17 The fill procedure Description The fill procedure fills all the bytes in a variable with a specified value Parameter 1 The first parameter is a reference to the variable whose bytes are to be filled 2 The second parameter is an expression of integral type and specifies the value used to fill the bytes in the variable Portability Operating Systems All Standard Pascal No 7 4 18 The flush procedure Description The flush procedure flushes a file or pipe i e all data waiting in memory to be written is written Parameter The flush procedure s only parameter is a reference to the file variable associated with the file or pipe to be flushed The file variable must be open before calling this function Portability Operating Systems All Standard Pascal No 7 4 19 The fsplit procedure Description The fsplit procedure splits a filename into its component parts Parameter 1 The first parameter is an expression of string type or char type which contains the filename to be split 2 The second parameter is optional and if supplied is a reference to the string variable which will store the directory folder part of the filename If this parameter is not supplied then the directory folder part of the filename is not stored 3 The third parameter is optional and if supplied is a r
103. variable is a reference to a record variable and field specifier and field designator identifier are field names NOTE field designator identifier can be used only in the statement part of a with statement 6 11 Set variables Description Set variables are used to store values of set types Example The following simple example program shows a typical use of set variables to classify values The program operates as follows First the set variable letters is initialized with the set of characters containing all lowercase and uppercase characters Next the set variable digits is initialized with the set of characters containing all the digits Next the user is prompted to enter a character and this character is read in Finally the character is classified by checking whether it is a member of letters digits or neither NOTE Sets are often used like this as an alternative to using a big case statement program classify input output var letters digits set of char c char begin letters a t z A Z digits i MOM wh Jey write Enter a character read c f c in letters then 3 writeln You entered a letter else if c in digits then writeln You entered a digit e w lse riteln You entered a symbol end 6 12 String variables Description String variables are used to store values of string types i e variable length sequences of characters The maximum num
104. what are program parameters for a description of the binding of program parameters to entities external to the program 18 1 What are errors ISO IEC 7185 defines an error as follows A violation by a program of the requirements of this International Standard that a processor is permitted to leave undetected ISO IEC 7185 then goes on to add the following two notes 1 Ifitis possible to construct a program in which the violation or non violation of this International Standard requires knowledge of the data read by the program or the implementation definition of implementation defined features then violation of that requirement is classified as an error Processors may report on such violations of the requirement without such knowledge but there are always remain some cases that require execution simulated execution or proof procedures with the required knowledge Requirements that can be verified without such knowledge are not classified as errors 2 Processors should attempt the detection of as many errors as possible and to as complete a degree as possible Permission to omit detection is provided for implementations in which the detection would be an excessive burden Below are links to documentation of how Irie Pascal handles all errors Most of the time the documentation consists only of a statement about whether or not the error is reported The description of each error is taken from ISO IEC 7185 Array index out of bounds
105. 0 if isdir then writeln s is a directory else writeln s is not a directory write Owner permissions if mode and usr _r lt gt 0 then write Read if mode and usr_w lt gt 0 then write Write if mode and usr_x lt gt 0 then if isdir then write Search else write Execute writeln end Portability Operating Systems Al1l Standard Pascal No 4 2 56 usr_Ww Description usr_w can be AND d see and operator bitwise with the filemode retrieved by the built in procedure getfilemode to determine whether the owner of a file or directory folder has permission to write to the file or directory folder Example For example the simple program below asks for a filename and then displays the file permissions for the owner of the file program OwnerPermissions input output var s filename mode integer isdir boolean begin write Enter filename readin s s fexpand s getfilemode s mode isdir mode and dir bit lt gt 0 if isdir then writeln s is a directory else writeln s is not a directory write Owner permissions if wW i f mode and usr r lt gt 0 then rite Read f mode and usr w lt gt 0 then rite Write f mode and usr x lt gt 0 then Fah sh w i if isdir then write Search else write Execute writeln Portability Operating Sy
106. 10 2 4 Assignment compatibility with read When using the built in procedure read to retrieve a value from a file into a variable the value shall be assignment compatible with the type of the variable For example given var s string 40 and read s then the value read in by read s must be assignment compatible with string 40 10 2 5 Assignment compatibility with assignment statements The value of the expression on the right hand side of an assignment statement shall be assignment compatible with the type of the left hand side For example given var age 0 100 and age v then v the right hand side of the assignment statement shall be assignment compatible with 0 100 the type of the left hand side of the assignment statement 10 2 6 Assignment compatibility with for The initial value and the final value in a for statement shall be assignment compatible with the type of the control variable if the statement contained in the for statement is executed For example given for i low to high do writeln i then low the initial value and high the final value shall be assignment compatible with the type of i the control variable if writeln i the statement in the for statement is executed NOTE writeln i will get executed unless low is greater than high 10 2 7 Assignment compatibility with transfer procedures In the statements pack a i z and unpack z a i the va
107. 11 Arguments The First Argument The first argument passed to the sendto function is the socket that you want to send data through The Second Argument The second argument passed to the sendto function is the operating system address of the buffer containing the data to be sent through the socket The type of this argument is address which means that you must use the built in function addr to pass the operating system address of the buffer The Third Argument The third argument passed to the sendto function is the number of bytes of data to be sent through the socket This argument can be zero and this case will be treated by implementations as successful and send will return zero as a valid value If the socket is connectionless a zero length transport datagram is sent The Fourth Argument The fourth argument passed to the sendto function can specify flags which influence the behavior of the send function The flags can be OR d or added together if more than one flag is being specified The flags which can be used are MSG _DONTROUTE Specifies that the data sent should not be subject to routing This flag may be ignored MSG OOB Sends OOB data through the socket If you do not wish to specify any flags then use zero as the value of this argument The Fifth Argument The fifth argument passed to the sendto function usually specifies the name of the destination socket or sockets that should receive the data being sent
108. 12 The Windows Sockets Library WinSock2 12 1 What are sockets 12 2 Introducing The WinSock2 library 12 3 Initializing the WinSock2 library 12 4 Cleaning up WinSock2 12 5 Checking for errors 12 6 Creating Sockets 12 6 1 Creating data sockets 12 6 2 Creating listening sockets 12 7 Binding Sockets 12 7 1 The bind function 12 8 Converting Data Sockets Into Listening Sockets 12 8 1 The listen function 12 9 Blocking 12 9 1 Dealing with blocking 12 9 2 The ioctlsocket function 12 9 3 The select function 12 10 Accepting Connections 12 10 1 The accept function 12 11 Making Connections 12 11 1 The connect function 12 12 Reading Data 12 12 1 Ther nction 12 12 2 The recvfrom function 12 13 Sending Data 12 13 1 The send function 12 13 2 The sendto function 12 14 How To Covert Names and IP Addresses 12 14 1 The gethostbyname function 12 14 2 The gethostbyaddr function 12 15 Closing Sockets 12 15 1 The shutdown function 12 15 2 The closesocket function 12 16 Some Other WinSock2 functions 12 16 1 The gethostname function 12 16 2 The getpeername function 12 16 3 The getsockname function 12 16 4 The getsockopt function 12 16 5 The htonl function 12 16 6 The htons function 12 16 7 The inet addr function 12 16 8 The inet _ntoa function 12 16 9 The ntohl function 12 16 10 The ntohs function 12 16 11 The setsockopt function 13 Appendix A Extensions to Pascal a
109. 4 in s str 1034 5 s will store Y 1034 ins str 7893 678 s will store 7 89E 03 ins str 7893 678 8 s will store 7 89E 03 ins str 7893 678 8 3 s will store 7893 678 ins Portability Operating Systems Al1l Standard Pascal No 7 4 57 The textbackground procedure Description The textbackground procedure sets the current text background color Calling this procedure does not immediately change the background color of the screen The background colors of characters already on the screen are not changed what this procedure does is to change the background color of characters written to the screen after the procedure is called The following table shows the values used to specify various background colors value color Black Blue Green Cyan Red agenta Brown Vhite YHA OPBWNEF CO Parameter The textbackground procedure s only parameter is an expression of integral type that specifies the new text background color Example J RRR KR RK KKK KK KKK KK I KR kk kkk kkk RK k kkk RK KK KK k k This program uses the built in procedure textbackground to change the background color If you are using Windows try running this program and see what happens J RRR KR KKK IKK KK k k k k k k k k k k k k k k k IA k k k k k kk k k k k k k k k k k k k k k k k k k program bc output W44 Suppress warning message about constant defined but no used since we already know we are not u
110. 5 maxbyte Example Below is a simple program that writes all possible values of byte to a file program bytes var f file of byte b byte begin rewrite f bytes da for b 0 to maxbyt write f b end Portability Operating Systems Al Standard Pascal No Description tT 4 e do I 5 15 6 char type char is the type identifier for a built in ordinal type with values of the current character set Example Below is a simple program that illustrates using char to do some file processing This program is used characters in the inpu to count the numbe file r of vowels and the total number of NOTE This program makes use of two features of Irie Pascal 1 If the user does not specify a command line parameter to match the program argument f then f is automatically assigned an empty string as its filename 2 If a file variable with an empty string as its filename is reset then the standard input file is associated with the file variable The net effect of these two features is that if you run this program and don t supply a program argument like ivm vowels then the program reads from the standad inp like ivm vowels fil From it Z program vowels f ou var f file of char tot vow integer CG char begin reset f tot 0 vow 0 while not eof f do begin read f c case c of tat let tity toft A R
111. 5 The int function 7 2 26 The ioresult function 7 2 27 The isalpha function 7 2 28 The isalphanum function 7 2 29 The isdigit function 7 2 30 The islower function 7 2 31 The isnull function 7 2 32 The isprint function 7 2 33 The isspace function 7 2 34 The isupper function 1 2 35 The isxdigit function 7 2 36 The keypressed function 7 2 37 The length function 7 2 38 The In function 7 2 39 The log function 7 2 40 The locase function 7 2 41 The lowercase function 7 2 42 The odd function 7 2 43 The ord function 7 2 44 The paramcount function 1 2 45 The paramstr function 7 2 46 The pi function 7 2 47 The platform function 7 2 48 The pos function 7 2 49 The pred function 7 2 50 The ptr function 7 2 51 The random function 7 2 52 The readkey function 7 2 53 The reverse function 7 2 54 The round function 1 2 55 The sin function 7 2 56 The sinh function 7 2 57 The sizeof function 7 2 58 The sqr function 7 2 59 The sqrt function 7 2 60 The stopserverviceevent function 7 2 61 The succe function 7 2 62 The supported function 7 2 63 The swap function 7 2 64 The system function 1 2 65 The tan function 7 2 66 The tanh function 7 2 67 The trim function 7 2 68 The trunc function 7 2 69 The unixplatform function 7 2 70 The upcase function 7 2 71 The uppercase function 7 2 72 The urldecode function 7 2 73 The version function 7 2 74 The wait function 1 2 75 The wherex function 7 2 76 The wherey function 7 3 User Declared Funct
112. 7 If you exceed this limit the Irie Pascal compiler issues a fatal error message Statement sequences can be nested to a maximum depth of 256 If you exceed this limit the compiler issues a fatal error message 15 4 Nesting of functions procedures Pascal supports nested functions and procedures i e functions and procedures can contain other functions and procedures Irie Pascal supports nesting functions and procedures to a maximum depth of 256 NOTE This does not mean that the total number of functions and procedures in a program is 256 This limits applies only to the depth of nesting If you exceed this limit the compiler issues a fatal error message 15 5 Range of variant selector s type amp Number of variants Irie Pascal limits the maximum range of the tag type of a variant record s variant selector to 1024 i e the maximum number of values specified by the tag type is 1024 This also indirectly limits the number of variants in a variant record s variant part to 1024 If you exceed this limit the compiler issues a warning message and the following checks are not performed on the variant record which exceeded the limit s No case constant should appears more than once Each value specified by the tag type should appear as a case constant Only active variants in variant records are accessed 15 6 Size of integer constants The maximum size of an integer constant is 4 294 967 295 If you exceed this limit the compiler will issue
113. 7 4 50 The rewrite procedure Description The rewrite procedure associates a file variable with a file i e opens the file variable and allows it to be used to manipulate the file The rewrite procedure opens the file variable in write only mode The open procedure can also be used to open file variables in write only mode Parameters 1 The first parameter is a reference to the file variable to open The second parameter is an expression of string type or char type and names the file variable referenced by the first parameter as if the built in procedure assign had been called NOTE This parameter is an extension to Standard Pascal The name of the file variable referenced by the first parmater controls which file is opened by the rewrite procedure If the name is a non empty string then a file with that name is opened If the name is an empty string then the file opened is either the standard output file or a temporary file with a system generated name depending on the project options set when the program was compiled File variables can get named in the following ways e By calling the built in procedure assign By supplying the second parameter when calling the built in procedures append open popen reset or rewrite By using the file variables as program parameters Portability Operating Systems Al1l Standard Pascal Yes 7 4 51 The rmdir procedure Description The rmdir procedure removes deletes a direct
114. Accessing inactive variant Dereferencing nil pointers Dereferencing undefined pointers Dangling pointers Altering file variables Using out of range value parameters Using out of range set value parameters Output to file not open for writing Output to undefined file Writing to middle of file Using Put on undefined buffer variables Resetting undefined files Input from file not open for reading Input from undefined file Reading past end of file Reading out of range values Writing out of range values new p cl cN constraints violated Incompatible use of dispose p Incompatible use of dispose p k1 kM dispose p k1 kM constraint violations disposing nil pointer disposing undefined pointer new p cl cM constraint violated Invalid use of pack 1 Invalid use of pack 2 Invalid use of pack 3 Invalid use of unpack 1 Invalid use of unpack 2 Invalid use of unpack 3 Square of large numbers In x and x is less than or equal to 0 Square root of negative number Problems with trunc Problems with round Problems with chr Problems with succ Problems with pred Using eof on undefined files Using eoln on undefined files Using eoln at end of file Using undefined variables Real division by zero Integer division by zero Modulus of zero or negative Integer overflow underflow Returning undefined value from function Assigning out of range ordinal values Assigning out of range set va
115. Arguments The only argument passed to the inet_addr function is the operating system address of the buffer containing the host address as a null terminated string You should use the the built in function addr to get the operating system address of this buffer Return Values The inet_addr function returns an unsigned long value containing the host address represented as a numeric value if the call is successful If an error occurs then the value IVADDR_NONE is returned Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 16 8 The inet_ntoa function Description The inet_ntoa function converts a host address from a numeric value into a null terminated string Declaration The system include file WinSock2 ine contains the following declarations for the in_addr type and the inet_ntoa function in_addr u_long function inet _ntoa inaddr in_addr address external dll ws2_32 d11 Arguments The only argument passed to the inet_ntoa function is host address represented as a numeric value Return Values The inet_ntoa function returns the operating system address of a buffer containing a null terminated string representing the Internet address if the call is successful If the call fails zero is returned When the inet_ntoa function call succeeds the buffer returned r
116. Attempt to create object failed 41 ObjectGetOrFuncFailure Attempt to get property to call method with no arguments failed 42 ObjectFuncFailure Attempt to call function method failed 43 ObjectProcFailure Attempt to call procedure method failed 43 ObjectPutFailure Attempt to set object property failed 44 ObjectGenericFailure Attempt to access generic object failed 45 MemoryAllocationFailure Attempt to allocate memory failed 46 InvokeException A generic object instance raised an exception 20 1 Grammar notation In this manual the syntax of the Irie Pascal language is described using a context free grammar Context free grammars are often used to describe the syntax of programming languages because they produce short and precise definitions A context free grammar breaks the syntax of a complex language into a number of simpler elements called non terminal symbols The syntax of each non terminal symbol is defined by a production Each production consists of a non terminal symbol followed by some sort of assignment operator and then followed by a sequence of special symbols terminal symbols and non terminal symbols The special symbols are used to describe how the other symbols can be combined The terminals symbols are literal text that can occur in the language being defined The full context free grammar takes the form of a sequence of productions for all the non terminal symbols in the language The context free grammar used in this manual h
117. CATMARK are declared in the system include file WinSock2 inc The Third Argument The third argument passed to the ioctlsocket function is of type u_ ong and is passed by reference You use this argument to further specify what the command should do or to retrieve values returned by the command Return Values The ioctlsocket function returns a value of integer type that indicates whether the call was successful A value of zero means that the call succeeded A value of SOCKET ERROR indicates that the called failed and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail NOTE The constant SOCKET ERROR is declared in the system include file WinSock2 inc Example The following code fragments illustrates how to enable socket s non blocking mode ulNonBlockingMode 1 iRet ioctlsocket s FIONBIO ulNonBlockingMode The code fragment above assumes that s is a socket that has already been created ulNonBlockingMode is a variable of type u_ ong and iRet is a variable of integer type NOTE The type u_ ong is declared in the system include file WinSock2 inc Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 9 3 The select function Description The select function checks whether one or more socket
118. GetLastError function to retrieve a code that identifies the error that caused the call to fail NOTE The constant SOCKET ERROR is declared in the system include file WinSock2 inc Example The following example function is taken from the sample sockets programs distributed with Irie Pascal and demonstrates how to create a socket bind it and convert it into a listening socket This function creates a listening socket First it creates a socket Then it binds the socket to a particular port i e the port we want to listen on The socket is not bound to any particular address INADDR_ANY is used instead because connections will be accepted from any IP address Finally listen is called to convert the socket to a listing socket function CreateListeningSocket port integer socket var s socket sa sockaddr_in iRet integer begin CreateListeningSocket s createsocket AF INET SOCK_STREAM 0 if s INVALID SOCKET then FatalSocketError CreateSocket call failed fill sa 0 sa sin_family AF_INET sa sin_port htonl port shr 16 sa sin_addr htonl INADDR_ANY shr 16 iRet bind s addr sa sizeof sa if iRet lt gt 0 then FatalSocketError Call to bind failed iRet listen s SOMAXCONN if iRet lt gt 0 then FatalSocketError Call to listen failed CreateListeningSocket s end CreateListeningSocket Reference Information The authoritat
119. If the name is a non empty string then a file with that name is opened If the name is an empty string then the file opened is either the standard output file or a temporary file with a system generated name depending on the project options set when the program was compiled File variables can get named in the following ways e By calling the built in procedure assign e By supplying the second parameter when calling the built in procedures append open popen reset or rewrite e By using the file variables as program parameters Example append f file txt opens a file named file txt Portability Operating Systems Al1 Standard Pascal No 7 4 3 The assert procedure Description The assert procedure is based on the C language macro of the same name The assert procedure can be enabled disabled using a compiler option When enabled the assert procedure evaluates its parameter which must be a boolean expression If the expression evaluates to false then the program is terminated If the expression evaluates to true then the procedure does nothing When disabled the assert procedure does nothing The idea behind the assert procedure is that you use it during debugging to test the values in your program and after your program is debugged you don t have to search your program and remove all the calls to this procedure instead you just disable it using a compiler option You should use the assert procedure only to test
120. Irie Pascal Programmer s Reference Manual Author Stuart King Page 1 TABLE OF CONTENTS 1 Introduction 1 1 Preface 1 2 Compliance statement 2 Language Elements 2 1 What are language elements 2 2 Character literals 2 3 Reserved words 2 4 Separators 2 5 Compiler directives 2 6 Special symbols 2 7 String literals 2 8 Numbers 2 8 1 Integers 2 8 1 1 What are integers 2 8 1 2 Integers Decimal notation 2 8 1 3 Integers Hexadecimal notation 2 8 1 4 Integers Binary notation 2 8 2 Real numbers 2 8 2 1 What are real numbers 2 9 Identifiers 2 9 1 What are identifiers 2 9 2 Built in identifiers 2 9 3 User defined declared identifiers 2 9 4 Directives 2 9 4 1 What are directives 2 9 4 2 The external directive 2 9 4 3 The forward directive 3 Labels 3 1 What are labels 4 Constants 4 1 What are constants 4 2 Built in Constant Identifiers 4 2 1 What are built in constant identifiers 4 2 2 appendmode 4 2 3 dir_bit 4 2 4 false 4 2 5 feature_calldll calling DLLs supported 4 2 6 feature_closedir closedir supported 4 2 7 feature_clrscr clrscr supported 4 2 8 feature_delay delay supported 4 2 9 feature_gotoxy gotoxy supported 4 2 10 feature_idispatch COM ActiveX objects supported 4 2 11 feature_intr intr supported 4 2 12 feature_keypressed keypressed supported 4 2 13 feature mysql MySQL databases supported 4 2 14 feature _ ODB taba r
121. It is an error to call the movenext method of a recordset object when the recordset is at end of file Portability Operating Systems Al1l Standard Pascal No 5 15 21 7 recordset field Description The field property of the recordset object type is used to retrieve the value of a field of the current record in the current recordset The isnull function can be used to test if the value of the field is NULL NOTE field is a read only property of type variant Currently this property is read only so you can not use it to change the contents of the record fields i e you can t use this property to change the database If you want to change the database call the execute method of the connection object type and pass in a SQL UPDATE statement Example For example if you have a recordset object reference rs with an open recordset and the records in the recordset have a field named last_name then rs field last_name constains the contents of the field last_name for the current record in the recordset NOTE Since this property is used so often you can leave out the name of the property i e field So for example rs last_name is equivalent to rs field last_name Portability Operating Systems Al1l Standard Pascal No 5 16 1 Type definitions Description Type identifiers are identifiers that have been associated with a type using a type definition Type definitions must be placed in type definition
122. KET buf address len flags integer integer external dll ws2_32 d11 Arguments The First Argument The first argument passed to the reev function is the socket that you want to read data from The Second Argument The second argument passed to the reev function is the operating system address of the buffer that you have supplied to store the data read from the socket The type of this argument is address which means that you must use the built in function addr to pass the operating system address of the buffer The Third Argument The third argument passed to the reev function is the length of the buffer you have supplied to store the data read from the socket The Fourth Argument The fourth argument passed to the reev function can specify flags which influence the behavior of the recv function The flags can be OR d or added together if more than one flag is being specified The flags which can be used are MSG PEEK Peeks at the data in the socket The data is copied from the socket into the buffer supplied but is not removed from the socket When this flag is used the recv function returns the number of bytes of data waiting available to be read MSG _OOB Read OOB data from the socket If you do not wish to specify any flags then use zero as the value of this argument Return Values The recv function returns the number of bytes read from the socket if the call is successful If the call fails the value
123. N You can access the MSDN on the Microsoft website at msdn microsoft com 13 1 What are extensions Standard Pascal i e ISO IEC 7185 allows implementations to include extensions to Pascal An extension is not allowed to invalidate any program that would be valid without the extension except those programs that are invalidated only because of new keywords added by the extension Irie Pascal supports a number of extensions to Standard Pascal Some of these extensions were added for compatibility with Turbo Pascal or Extended Pascal while others are specific to Irie Pascal Support for extensions can be enabled and disabled using the Extensions Project Options page see the Irie Pascal User s Manual for more information The Irie Pascal extensions are listed below Allow relaxed declarations Allow constant ranges Allow otherwise Allow relaxed parameter list congruity Allow non numeric statement labels Allow underscores in identifiers Allow binary and hexadecimal integers Auto declare Input and Output Allow double quoted literals Enable non standard operators Enable non standard constants Enable non standard types Enable non standard variables Enable non standard functions Enable non standard procedures 13 2 Allow relaxed declarations When the relaxed declarations extension is enabled declarations can occur before the reserved word program which normally marks the start of the program When t
124. NOTE It is an error if there is no character whose ordinal value is equal to the parameter Parameter The chr function s only parameter is an expression of integral type Example chr 64 returns assuming the ASCII or ANSI character set Portability Operating Systems Al1l Standard Pascal Yes 7 2 6 The concat function Description The concat function returns a string value formed by concatenating 1 e joining the parameters passed to it Parameters The concat function s parameters are one or more expressions of string type or char type Example concat abc 123 returns abc 123 Portability Operating Systems Al1l Standard Pascal No 7 2 7 The copy function Description The copy function accepts up to three of the parameters described below the last parameter is optional and returns a value of type string which is formed by copying zero or more characters from the first parameter Parameters 1 The first parameter S is an expression of type string or type char and contains the characters to be copied 2 The second parameter P is an expression of integral type and specifies the position in S of the first character to copy If P is greater than the number of charaters in S then no characters are copied 3 The third parameter N is an expression of integral type and specifies the number of characters to copy If N is omitted or is greater than the number of characters in S from P to t
125. Parameter The trunc function s only parameter is an expression of real type Example trunc 7 234 returns 7 Portability Operating Systems Al1l Standard Pascal Yes 7 2 69 The unixplatform function Description The unixplatform function returns a value of type boolean which indicates whether the program is running on a UNIX like operating system currently Linux FreeBSD Solaris x86 or Solaris Sparc If the program is running on a UNIX like operating system the value true is returned otherwise the value false is returned This function doesn t actually test the operating system the program is running on instead it tests the edition of the interpreter that is running the program It is assumed for example that the Linux version of the interpreter is running under Linux and the Windows version of the interpreter is running under Windows Parameter None Portability Operating Systems Al1l Standard Pascal No 7 2 70 The upcase function Description The upcase function returns the uppercase letter corresponding to the parameter passed to it NOTE If there is no uppercase letter corresponding to the parameter passed to it then the parameter is returned unchanged The type of the value returned by this function is always char Parameter The upcase function s only parameter is an expression of char type Example upcase a returns A upcase A returns A upcase h returns H upcase 1l returns
126. Parameter The sqr function s only parameter is a numeric expression i e an expression of integral type or of real type Example sqr 1 returns 1 sqr 3 returns 9 sqr 5 returns 25 Portability Operating Systems Al1l Standard Pascal Yes 7 2 59 The sqrt function Description The sqrt function returns the square root of the value of the parameter passed to it The type of the value returned by this function is always real Parameter The sqrt function s only parameter is a numeric expression i e an expression of integral type or of real type Example sqrt 10 sqrt 9 returns 3 0 sqrt 5 0 Portability Operating Systems Al1l Standard Pascal Yes 7 2 60 The stopserverviceevent function Description The stopserviceevent function returns the handle associated with the StopServiceEvent that is sent to services as a signal to stop running This function returns zero if the program is not a service The type of the value returned by this function is always word This function is usually used with the wait function in services to repond to requests to stop running See the Irie Pascal User s Manual for more information about writing services Parameter None Portability Operating Systems Al1l Standard Pascal No 7 2 61 The succ function Description The succe returns the ordinal value that is the successor of the parameter passed to it It is an error if the parameter does not have a succs
127. Password end else if supported feature mysql then begin sUser GetStringValue Enter user id sPassword GetStringValue Enter password s MYSQL user sUsert password sPassword socket tmp mysql sock end else DisplayError No database support detected GetConnectionString s end begin new conn conn open GetConnectionString Add code here to process database conn close dispose conn end Portability Operating Systems All Standard Pascal No 5 15 20 2 connection close Description The close method procedure of the connection object type is used to close an open connection to a database engine Example For example if conn is a connection object reference with an open connection to a database engine then the following conn close will close the connection Portability Operating Systems Al1l Standard Pascal No 5 15 20 3 connection execute Description The execute method procedure of the connection object type is used to send an SQL statement to a database engine through an open connection Example For example if conn is a connection object reference with an open connection to a database engine then the following conn execute create database test will send the SQL statement create database test to the database engine at the other end of the connection Portability Operating Systems Al1l Standard Pascal No 5 15 20 4
128. SOCKET ERROR is returned and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail NOTE The constant SOCKET ERROR is declared in the system include file WinSock2 inc If the socket on the other end of the connection has gracefully closed the connection then zero is returned connection oriented sockets only Example The following function is taken from the sample program wSpamFilter and uses the recv function to read data from a socket The function SocketReadyForReading is defined by the sample program and checks whether there is data waiting to be read from a socket The type LineType is a cstring type PURPOSE Reads data from a socket PARAMETER S 1 buffer used to store the data read 2 wMaxWait maximum number of ms to wait for the socket to become ready GLOBAL s 1 DataSocket The socket to read from NOTES The socket is checked to make sure it is ready for reading before attempting to read This makes it unlikely that the application will become blocked waiting for data to come in procedure ReadDataSocket var buffer LineType wMaxWait word var iDataRead integer begin ReadDataSocket buffer if SocketReadyForReading DataSocket wMaxWait then begin writeln Reading LogMessage Reading iDataRead recv DataSocket addr buffer sizeof buffer 2 0 if iDataRead
129. SOCKET ERROR then FatalSocketError Call to recv failed else if iDataRead gt 0 then buffer iDataRead 1 chr 0 end end ReadDataSocket Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 12 2 The recvfrom function Description The recvfrom function reads data from a socket and optionally retrieves the name of the socket that sent the data The reevfrom function can be used on connection oriented sockets e g stream sockets or connectionless sockets e g datagram sockets Before calling the reevfrom function to read data from a socket a local name must have been assigned to the socket this can be done explicitly with the bind function or implicitly with the sendto function If there is no data available to be read from the socket then what happens next depends on whether the socket has it s non blocking mode enabled or disabled see dealing with blocking for more information about the non blocking mode of sockets Non blocking mode disabled If the socket has it s non blocking mode disabled and there is no data available to be read from the socket then the reevfrom function will block and wait for data to become available to be read from the socket or for the connection to be closed connection oriented sockets only or for the connection to be r
130. Sock2 library DLL to be unloaded from memory In order to prevent loss of data your program should call the shutdown function before calling the closesocket function and the WSACleanUp function There must be a call to the WSACleanUp function for every successful call to the WSAStartup function made by your program Only the final call to the WSACleanUp function does the actual cleanup The preceding calls simply decrement an internal reference count in the Ws2_32 dll Declaration The system include file WinSock2 ine contains the following declaration for the WSACleanUp function function WSACleanup integer external dll ws2_32 d11 Arguments None Return Values The WSACleanUp function returns a value of integer type that indicates whether the call was successful A value of zero means that the call succeeded A value of SOCKET_ERROR indicates that the called failed and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail Sample Program The sample program below illustrates how to call the WSAStartup and WSACleanUp functions I winsock2 inc program start output var data WSADATA iRet integer begin iRet WSAStartUp 0202 data if iRet lt gt 0 then begin writeln WSAStartUp call failed Return Code iRet halt end writeln WSAStartUp call succeeded writeln Version hex data wVersion w
131. T it 0 vow vow 1 otherwise end tot tot 1 end writeln Total chara ut file If you run name then the prog tput Tal y cters read r ram will open filename and read tot this program with a program argument writeln Vowels read vow end Portability Operating Systems Al1l Standard Pascal Yes 5 15 7 dir type Description dir is the type identifier for a built in type whose values are directory handles NOTE Directories are also called folders Example Below is a simple program that lists all the directories in the current directory program listdir output var d 3 dix filename string function IsDir name filename boolean var mode integer begin getfilemode name mode IsDir mode and dir bit lt gt 0 end begin opendir d Open current directory repeat readdir d filename Get next file in directory if the next file exists and it is a directory then list it if filename lt gt and IsDir filename then writeln filename until filename closedir d Close directory end Portability Operating Systems Al1l Standard Pascal No 5 15 8 double type Description double is a synonym for real Portability Operating Systems Al1l Standard Pascal No 5 15 9 error type Description error is the type identifier for a built in record typ
132. The Fifth Argument The fifth argument passed to the getsockopt function is the length of the buffer you supplied to store the value of the socket option After the getsockopt function returns successfully this argument will contain the actual length of the socket option value stored in the buffer Return Values The getsockopt function returns a value of integer type that indicates whether the call was successful A value of zero means that the call succeeded A value of SOCKET ERROR indicates that the called failed and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail NOTE The constant SOCKET ERROR is declared in the system include file WinSockz2 inc Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 16 5 The htonl function Description The htonl function converts a value of type u_ ong from host to TCP IP network byte order which is big endian Declaration The system include file WinSock2 inc contains the following declarations for the u_long type and the htonl function u_long word function htonl hostlong u_long u_long external dll ws2_32 d11 Arguments The only argument passed to the htonl function is the u_ ong value that you want to convert to TCP IP network byte order
133. a unique name is assigned to the socket by the system and the socket is marked as bound Declaration The system include file WinSock2 ine contains the following declaration for the connect function function connect s SOCKET name address namelen integer integer external dll ws2_32 d11 Arguments The First Argument The first argument passed to the connect function is either the socket that you want to send a connection request from connection oriented sockets only or the socket for which you want to specify a name for default destination and source sockets connectionless sockets only The Second Argument The second argument passed to the connect function is either the name of the listening socket that you want to send a connection request to connection oriented sockets only or the name of the default destination and source sockets connectionless sockets only The Third Argument The third argument passed to the connect function is the length of the name passed in the second argument Return Values The connect function returns a value of integer type that indicates whether the call was successful A value of zero means that the call succeeded A value of SOCKET ERROR indicates that the called failed and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail Example The following example function is taken from the sample sockets p
134. a pair of ordinal expressions If the member designator contains a single ordinal expression them the value of this expression is the set element that is present If the member designator contains a pair of ordinal expressions then the member designator specifies a range of set elements that are present and the value of the first ordinal expression is the first set element in the range and the value of the second ordinal expression is the last set element in the range A set constructor with no member designators is valid and denotes the empty set i e no set elements are present Example Here are some examples of set constructors the empty set true set of boolean with only truepresent a z A Z set of char with all the lowercase and uppercase letters present Syntax NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax set constructor member designator member designator member designator ordinal expression ordinal expression ordinal expression expression 8 3 1 What are type conversion rules Description Type conversion is the process of converting an operand of one type into an operand of another type and is usually done to convert one operand to the same type as another operand before performing an operation involving both operands For example if a value of integer type is to be added to a value of real type then the valu
135. a way that case is not significant and if there is a match then an ODBC connection is to be opened Since case is not significant in this comparision the connection type specifier could be lowercase as in odbc uppercase as in ODBC or mixed case If the connection type specifier does not match ODBC then it is compared with MYSQL again in such a way that case is NOT significant If the connection type specifier matches MYSQL then a MySQL connection is to be opened It is an error if the connection string is not prefixed by a connection type specifier or if the connection type specifier does not match either ODBC or MYSQL Opening ODBC Connections Next if an ODBC connection is to be opened then the connection string must be in one of the following two forms odbc connection string odbc connection string 1 odbc connection string 2 odbc connection string 1l dsn parm uid parm pwd parm driver specific text dsn parm DSN name uid parm UID uid pwd parm PWD password odbc connection string 2 name uid password where indicate optional parameters For exampl DSN test UID sa PWD When the connection string is in the first form then it is passed without further processing to the ODBC API function SQLDriverConnect to open the connection When the connection string is in the second form then the name id and password parameters are extracted from the connection string if present a
136. ace character is at position 32 then ord 32 16 7 Characters prohibited from text files 6 4 3 5 There shall be an implementation defined subset of the set of char type values designated characters prohibited from text files This appears to be a loophole provided by ISO IEC 7185 to allow implementations to get around the requirements specified for text files especially the requirement that all characters written to a text file appear when the text file is read in Irie Pascal designates one character as prohibited from text files This character is chr 26 also known as the End Of File EOF character NOTE The fact that the EOF character is prohibited from text files doesn t mean that you can t write them to text files but if you do then the text file will be terminated at that point i e the EOF and the characters written after the EOF will not appear when the text file is read back in Since this technically violates the standard EOF s are prohibited from text files 16 8 When I O is performed mon 6 6 5 2 The point at which the file operations rewrite put reset and get are actually performed is implementation defined Irie Pascal implements lazy I O i e input operations are performed at the latest opportunity and output operations are performed at the earliest opportunity in order to facilitate interactive terminal input and output The file operations are performed as specified below rewrite the
137. adin FromAddress write Enter the to address readin ToAddress objMail CreateObject CDONTS NewMail string objMail Send FromAddress ToAddress Testing dispose objMail end This is a test message NORMAL Syntax The syntax for defining a new generic object type is given below object type object class The keywords object and class can be used interchangably for now however in later versions of Irie Pascal which will more fully support Object Pascal these keywords may produce slightly different effects There appears to be two specifications for Object Pascal The first specification is simplier and uses the keyword object and appears to be most popular on the Apple Mac While the second specification is more sophisticated and uses the keyword class Later versions of Irie Pascal may attempt to support both specifications of Object Pascal 5 15 1 The built in type identifiers Built in type identifiers are automatically defined by the compiler Unlike reserved words you can define your own identifiers with the same spelling as built in type identifiers if you do then your definition will override the definition made by the compiler The built in type identifiers are listed below address type binary type boolean type byte type char type connection type dir type double type error type filename type integer type real type recordset type registers type r
138. ailed 19 FileBufferIsEmpty Attempt to use put and the file buffer is empty 20 ChDirFailure Attempt to change directory failed 21 FileExpandFailure Attempt to use fexpand failed 22 FileSplitFailure Attempt to use fsplit failed 23 FileSizeFailure Attempt to obtain size of file failed 24 FileOpenDirFailure Attempt to open directory failed 25 FileReadDirFailure Attempt to read directory entry failed 26 DirectorylIsUndefined Attempt to access directory variable failed 27 FileCloseDirFailure Attempt to close directory failed 28 FileRewindDirFailure Attempt to rewind directory failed 29 FileMkDirFailure Attempt to create directory failed 30 FileRmDirFailure Attempt to remove directory failed 31 FileGetDateFailure Attempt to get the date a file was last modified failed 32 FileGetModeFailure Attempt to get the mode of a file failed 33 FileGetTimeFailure Attempt to get the time a file was last modified failed 34 FileSetDateFailure Attempt to set the date a file was last modified failed 35 FileSetTimeFailure Attempt to set the time a file was last modified failed 36 FileRawReadFailure Attempt to use rawread failed 37 FileRawWriteFailure Attempt to use rawwrite failed 38 FileInternalFailure THIS SHOULD NEVER OCCUR 39 DatabaseFailure Attempt to access database failed 40 ObjectCreateFailure
139. ally used for this purpose The problem is if a parameter is declared as a var parameter in Pascal you can t pass a value like zero and any variable you do pass will have a non zero address The solution is to pass the special variable null which has an address of zero Operating Systems Al1l Standard Pascal No 6 13 6 output Description output is the variable identifier for a built in file variable associated with the standard output stream The standard output stream is usually connected to the screen Portability Operating Systems Al1l Standard Pascal Yes 6 14 1 Variable Declarations Description Variable identifiers are identifiers that have been associated with a variable using a variable declaration Variable declarations must be placed in variable declaration groups Example Here is an example of a variable declaration group var name string age heigth integer Syntax The syntax for variable declaration groups is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax variable declaration group var variable declaration variable declaration identifier letter letter digit identifier list identifier identifier new ordinal type enumerated type subrange type new pointer typ A domain type domain type new structured type packed Jarray type packed record type packe
140. ammar for the full syntax label declaration group label label label label digit sequence identifier digit sequence digit digit digit r rAr t2 3 4 75 6 7 B 19 4 1 What are constants Constants can be character literals string literals integers real numbers or constant identifiers Constant identifiers are identifiers that have been associated with a constant by a constant definition or by an enumerated type definition Example Here is an example of a constant definition group const Space message Hello first 1 last 10 DaysInYear 365 25 minint maxint linefeed 10 4 2 1 What are built in constant identifiers Built in constant identifiers are automatically defined by the compiler Unlike reserved words you can declare your own identifiers with the same spelling as built in constant identifiers if you do then your declaration will override the definition made by the compiler The built in constant identifiers are listed below appendmode dir bit e false feature_calldll feature_closedir feature_clrscr feature_delay feature_gotoxy feature_idispatch feature_intr feature_keypressed feature_mysql feature_odbc feature_opendir feature_popen feature_readdir feature_readkey feature_rewinddir feature_textbackground feature_textcolor feature_wherex feature_wherey grp r grp w grp x maxbyte max
141. an error Error Handling This error is never reported 18 38 Problems with chr Official Description 6 6 6 3 For chr x the function returns a result of char type that is the value whose ordinal number is equal to the value of the expression x if such a character value exists It is an error if such a character value does not exist Error Handling This error is always reported 18 39 Problems with succ Official Description 6 6 6 4 For succ x the function yields a value whose ordinal number is one greater than that of x if such a value exists It is an error if such a value does not exist Error Handling This error is reported if range checking is enabled 18 40 Problems with pred Official Description 6 6 6 4 For pred x the function yields a value whose ordinal number is one less than that of x if such a value exists It is an error if such a value does not exist Error Handling This error is reported if range checking is enabled 18 41 Using eof on undefined files Official Description 6 6 6 5 When eof f is activated it is an error if f is undefined Error Handling This error is reported if I O checking is enabled 18 42 Using eoln on undefined files Official Description 6 6 6 5 When eoln f is activated it is an error if f is undefined Error Handling This error is reported if I O checking is enabled 18 43 Using eoln at end of file Official Description 6 6 6 5 When eoln f
142. an type and is equal to true if either operand is true and false if both operands are false Short circuit evaluation is always used by the or_else operator i e The left operand is evaluated first and if it is true then the right operand is not evaluated because the result of the operation must be true Example false or_else fals results in false false or_else tru results in true tru or_else fals results in true tru or_ else tru results in true The differences between the or_else operator and the or operator are The or_else operator can not be used to perform bitwise OR e Short circuit evaluation is always used when by the or_else operator but can be enabled disabled for the or operator 8 4 5 7 xor boolean Description As an extension to Standard Pascal Irie Pascal supports the xor operator which when used with operands of boolean type performs boolean XOR The result of the operation is of boolean type and is equal to true if one but not both operands are true and false if both operands are false or both operands are true Example false xor false results in false false xor true results in true true xor false results in true true xor true results in false 8 4 6 1 The string operators The only string operator is string concatenation 8 4 6 2 String concatenation Description As an extension to Standard Pascal Irie Pascal supports us
143. appable errors and report any errors detected If you want more control on how errors are handled you can disable error trapping using the built in procedure TrapErrors and then use the function GetLastError to check the last trappable error that occured Value Error Code Cause 0 NoErrors I O operation completed successfully 1 FileEraseFailure Attempt to erase a file failed 2 FileRenameFailure Attempt to rename a file failed 3 FileIsUndefined Attempt to operate on an undefined file 4 FileIsOpen Using assign erase or rename on an open file 5 FileIsNotOpen Attempt to perform I O on a closed file 6 FileModeUndefined THIS SHOULD NEVER OCCUR 7 FileNameTooLong Attempt to give a file a name too long 8 FileNameNotDefined Attempt to erase or rename a file with no name 9 FilePosFailure Attempt to use pos on a file failed 10 FileSeekFailure Attempt to use seek on a file failed ll NotOutputFile Attempt to write to a file not open for writing 12 UnexpectedEOF Attempt to read past end of file 13 WriteFailure Attempt to write to file failed 14 WidthTooLarge Attempt to write a field too wide 15 NotInputFile Attempt to read from a file not open for reading 16 ReadFailure Attempt to read from file failed 17 ClosingFailure Attempt to close a file failed 18 OpeningFailure Attempt to open a file f
144. aracter of True and False used on output of values of boolean type is implementation defined Irie Pascal uses true and false on output of values of boolean type 16 17 Effect of built in procedure page 6 9 5 The effect of the procedure page when applied to a text file which is in generation mode is implementation defined The procedure page causes a form feed character i e chr 12 to be written to text files to which it is applied 16 18 Binding of file type program parameters 6 10 The binding of a file type program parameter is implementation defined See what are program parameters for a description of how file type program parameters are handled 16 19 Effect of reset and rewrite on input and output 6 10 The effect of reset and rewrite on the standard files input and output is implementation defined reset and rewrite have no effect on the standard files input and output 17 1 Implementation dependent features The Pascal Standard ISO IEC 7185 does not completely define all features of the language Some features are implementation dependent Below are links to the definitions of how Irie Pascal treats all implementation dependent features Each definition has the following format First the official description of the feature is taken from ISO IEC 7185 and displayed in red This is followed by a simplified description if the official description is unclear or requires the reader to have a
145. ard Pascal No 7 4 40 The put procedure Description The put procedure writes the contents of a file s buffer variable to the file and empties the file s buffer variable leaving it undefined NOTE This procedure is seldom used since it is usually easier to use the write or writeln procedures Parameter The put procedure s only parameter is a reference to the file variable associated with the file to be written to The file variable must be open before calling this function Example The simple program below uses the built in procedure put to write a message to the standard output program hello2 output begin output H put output output e put output output 1 put output output 1l put output output o put output output put output output w put output output o put output output r put output output 1 put output output d put output output put output output put output end Portability Operating Systems Al1l Standard Pascal No 7 4 41 The randomize procedure Description The randomize procedure initializes the random number generator with a seed The random number generator is a psuedo random number generator i e the sequence of numbers generated appears to be random but the same sequence of numbers is generated every time the same seed is used Param
146. as the following notation The equal sign i e is used as the assignment operator in productions to separate the non terminal symbol being defined from its definition The special symbols are and The symbol is used to separate alternatives i e the grammar allows either the symbols on its left hand side or the symbols on its right hand side The symbols are used to enclose symbols that can appear zero one or more times The symbols are used to enclose optional symbols i e symbols that can appear zero or one time The symbols are used to group symbols that are evaluated together The terminal symbols appear in boldface and are enclosed in single quotation marks to distinguish them from non terminal symbols For example here are the productions that define the syntax for identifiers identifier letter letter digit letter a b e d e f g h j i j a a e a maa to phi tg tet ts S A Tulliv w a yz J digit 0 1 2 3 4 5 6 7 8 9 These productions mean An identifier is a letter followed by zero or more letters or digits A letter is one of the listed characters i e a z or an underscore A digit is one of the decimal numerals The complete grammar for Irie Pascal is given in here 20 2 Irie Pascal grammar The start symbol for this grammar is program actual parameter expression variable access procedure identifier function identifier
147. atform_dos Description platform_dos can be compared with the value returned by the built in function platform to determine whether the current platform is DOS i e the interpreter running your program is from the DOS edition of Irie Pascal Example The following simple program displays the current platform program ShowPlatform output begin case platform of platform dos writeln DOS platform_os2 writeln 0S 2 platform win32 writeln Windows platform linux writeln Linux platform fbsd writeln FreeBSD platform solaris writeln Solaris x86 platform solaris sparc writeln Solaris Sparc platform error writeln Unknown Platform end end Portability Operating Systems Al1l Standard Pascal No 4 2 36 platform_error Description platform_error is returned by the built in function platform when the current platform is unknown NOTE This can not happen using the current or previous versions of Irie Pascal Example The following simple program displays the current platform program ShowPlatform output begin case platform of platform dos writeln DOS platform _os2 writeln 0S 2 platform _win32 writeln Windows platform linux writeln Linux platform fbsd writeln FreeBSD platform solaris writeln Solaris x86 platform solaris sparc writeln Solaris Sparc platfor
148. ating Systems Al1l Standard Pascal No 7 4 48 The reset procedure Description The reset procedure associates a file variable with a file i e opens the file variable and allows it to be used to manipulate the file The reset procedure opens the file variable in read only mode The open procedure can also be used to open file variables in read only mode Parameters 1 The first parameter is a reference to the file variable to be opened 2 The second parameter is an expression of string type or char type and names the file variable referenced by the first parameter as if the built in procedure assign had been called NOTE This parameter is an extension to Standard Pascal The name of the file variable referenced by the first parmater controls which file is opened by the reset procedure If the name is a non empty string then a file with that name is opened If the name is an empty string then the file opened is either the standard output file or a temporary file with a system generated name depending on the project options set when the program was compiled File variables can get named in the following ways e By calling the built in procedure assign By supplying the second parameter when calling the built in procedures append open popen reset or rewrite By using the file variables as program parameters Example The program below is used to count the number of vowels and the total number of characters in
149. ation about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 3 Initializing the WinSock2 library The WSAStartUp Function Description The WSAStartUp function initializes the WinSock2 library for use by your program and must be the first WinSock2 library function called by your program Calling the WSAStartUp function serves two major purposes The first purpose is to load the DLL that implements the WinSock2 library i e Ws2_32 dll NOTE The other WinSock2 library functions expect the WinSock2 library DLL to be loaded before they are called The second purpose for calling the WSAStartUp function is to establish what version of the Windows Sockets API your program should use Declaration The system include file WinSock2 ine contains the following declaration for the WSAStartUp function function WSAStartup wVersionRequested shortword var lpWSAData WSADATA integer external dll ws2_32 d11 Arguments The First Argument The first argument passed to the WSAStartUp function is an expression of shortword type This argument indicates the highest version of the Windows Sockets API that your program can support Bits 0 through 7 i e the least significant byte specify the major version number of the API Bits 8 through 15 i e the most significant byte specify the minor version number of the API So to specify that the highest W
150. ause a trappable error Then call getlasterror to determine which category of error occured if any You will probably want to turn automatic error trapping back on with TrapErrors true after executing the code that might cause a trappable error The I compiler directive also turns automatic error trapping off and on however new programs should use the traperrors procedure instead Use of the I compiler directive continues to be supported for compatibility reasons only Parameter The traperrors procedure s only parameter is an expression of boolean type that specifies wether automatic error trapping is being turned on or off Example The following simple program asks for the name of a file and then deterines whether the fil xists It determines whether the file exists by checking whether the file can be opened fo reading So technically it is really testing whether the fil file exists AND also if the user has read access to the file Anyway the built in procedure trapperrors is used to turn o error trapping before the program attempts to open the file this prevents the normal error trapping procedure from the program if the file can not be opened Then the built in getlasterror is called to determine if an error occured If occured this program just assumes that the file does not exis program DoesFileExist input output var n filename
151. ax are omitted see Irie Pascal Grammar for the full syntax function declaration function heading directive function identification function block function heading function block block declarative part statement part compound statement begin statement sequence end declaration group label declaration group constant definition group type definition group variable declaration group function declaration procedure declaration declarative part declaration group directive forward directive external directive variable parameter specification procedure parameter specification function parameter specification Function block block fFunction identifier identifier function parameter specification function heading identifier letter letter digit identifier list identifier identifier formal parameter section value parameter specification fFunction heading function identifier formal parameter list Function identification function function identifier procedure identifier identifier result type type identifier statement part compound statement statement sequence statement statement type identifier identifier procedure identification procedure procedure identifier procedure parameter specification procedure heading es
152. below and_then or_else shl bit shift left shr bit shift right xor boolean xor bitwise The standard operators that can be used in non standard ways are listed below not bitwise and bitwise or bitwise string concatenation 13 12 Enable non standard constants When the enable non standard constants extension is enabled Irie Pascal supports the use of the following non standard constants appendmode dir_bit feature_calldll feature_closedir feature_clrscr feature_delay feature_gotoxy feature_idispatch feature_intr feature_keypressed feature_mysql feature_odbc feature_opendir feature_popen feature_readdir feature_readkey feature_rewinddir feature_textbackground feature_textcolor feature_wherex feature _wherey grp r grp w grp x maxbyte maxchar maxword oth_r oth w oth x platform dos platform error platform fbsd platform linux platform_os2 platform_solaris platform solaris sparc platform win32 readmode rsdefault rsdynamic rsforward rskeyset rsstatic sql_te_all sql tc ddl commit sql tc ddl ignore sql_tc_dml sql_tc_none usr r usr_w usr x writemode 13 13 Enable non standard types When the enable non standard types extension is enabled Irie Pascal supports the use of the following non standard types address type binary type byte type connection type dir type double type error type filename type list types recordset t
153. ber of characters allowed in each sequence is fixed and is defined when the string type is defined The individual characters in a string can be referenced using a similiar syntax to the that used to reference individual array elements Example For example if name is a string variable containing the string Bob then name 1 accesses the first character in the string i e B and name 2 accesses the second character in the string i e o The operator can be used to perform string concatenation i e joining For example here is a hello world program using string concatenation program good output begin writeln hello world end Syntax The syntax for accessing individual elements in a string is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax indexed variable string string variable integral expression integral expression expression string variable variable access where string variable is a reference to a string variable and integral expression is an expression which evaluates to the position of the string element being accessed 6 13 1 The built in variable identifiers Built in variable identifiers are automatically declared by the compiler Unlike reserved words you can declare your own identifiers with the same spelling as built in variable identifiers if you do then your declaration will override the declaration mad
154. bits in the operands and the result The example above could have been written as 28 or 23 results in 31 which is the same thing but is probably not as clear 8 4 8 5 xor bitwise Description When the xor operator has operands of integral type then it performs bitwise exclusive or The result of the operation is of integral type and has its bits set as follows each bit is one 1 in the result if and only if one of bits in the corresponding position in the operands is one 1 but not both Example 11100 xor 10111 results in 01011 Binary notation is used in the example above so that you can clearly see the individual bits in the operands and the result The example above could have been written as 28 xor 23 results in 11 which is the same thing but is probably not as clear 8 4 8 6 Bit shift left shl Description As an extension to Standard Pascal Irie Pascal supports the shl operator which takes two operands of integral type and performs a left bit shift The result of the operation is of integral type and is calculated by shifting to the left the bits in the left operand by the number of places specified by the right operand The right operand must be greater than or equal to zero NOTE Bit shifting left by N bits is the same as multiplying by 2 raised to the Nth power for positive operands Example 11100 shl 3 results in 11100000 Binary notation is used in the example above so that you can clearly see the indiv
155. ble r and an integer variable x the following val 1123 45 rp x will store 123 45 in r and 0 in x Portability Operating Systems All Standard Pascal No 7 4 62 The write procedure Description The write procedure writes values to the file associated with a file variable Parameters 1 The first parameter is optional and if supplied is a reference to the file variable associated with the file to write to If this parameter is not supplied then the write procedure writes values to the file associated with output 2 The other parameters are called write parameters and specify the values to be written to the file Example write true writes true write true 2 writes tr write 3567 writes 3567 write 3567 1 writes 3567 write 1 2345678 writes 1 23E 00 write 1 2345678 8 writes 1 2E 00 write 1 2345678 8 3 writes 1239 Portability Operating Systems Al1l Standard Pascal Yes 7 4 63 The writeln procedure Description The writeln procedure writes a line into a text file Parameter 1 The first parameter is optional and if supplied is a reference to the file variable associated with the file to write to If this parameter is not supplied then the writeln procedure writes lines to the file associated with output 2 The other parameters are optional and if supplied are write parameters that specify the value
156. byte is equal to the largest byte value supported by Irie Pascal 1 e 255 Portability Operating Systems Al1l Standard Pascal No 4 2 28 maxchar Description maxchar is equal to the largest character value supported by Irie Pascal i e 255 Portability Operating Systems Al1l Standard Pascal No 4 2 29 maxint Description maxint is equal to the largest supported integer value i e 2 147 483 647 Portability Operating Systems Al1l Standard Pascal Yes 4 2 30 maxword Description maxword is equal to the largest supported word value i e 4 294 967 295 Portability Operating Systems Al1l Standard Pascal No 4 2 31 nil Description nil is a pointer value which is compatible with all pointer types This constant can be assigned to any pointer variable to indicate that the variable doesn t point anywhere and any pointer variable can also be compared with nil As an extension to Standard Pascal nil is also a object value which is compatible with all object types This constant can be assiged to any object reference to indicate the the reference doesn t point at any object and any object reference can be compared with nil Portability Operating Systems Al1l Standard Pascal Yes 4 2 32 oth_r Description oth_r can be AND d see and operator bitwise with the filemode retrieved by the built in procedure getfilemode to determine whether users not belonging to the same group as the owner of a fil
157. call was successful A value of zero means that the call succeeded A value of SOCKET_ERROR indicates that the called failed and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail NOTE The constant SOCKET ERROR is declared in the system include file WinSock2 inc Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 16 3 The getsockname function Description The getsockname function retrieves a socket s name and can be useful in cases where you have not explicity assigned a name to the socket and the system has assigned a name for you One such case occurs if you use the connection function on a socket without first assigning a name to the socket with the bind function For connection oriented sockets you should not assume that the socket s address will available if the socket has been bound to an unspecified address using ADDR_ANY and the socket is not connected For connectionless sockets the address may not be available unil I O occurs on the socket Declaration The system include file WinSock2 ine contains the following declaration for the getsockname function function getsockname s SOCKET name address var namelen integer integer external dll wsock32 dl1l1 Arguments The Fir
158. ce to the directory variable to close Example Below is a simple program that lists all the files in the current directory program listfiles output var d s dir filename string begin opendir d Open current directory repeat readdir d filename Get next file in directory if filename lt gt then writeln filename until filename closedir d Close directory end Portability Operating Systems Al1l Standard Pascal No Description 7 4 8 The clrscr procedure The elrser procedure clears the screen and moves the cursor to the top left corner of the screen Parameter None Portability Operating Systems Al1l Standard Pascal No Description 7 4 9 The crc32 procedure The ere32 procedure computes a 32 bit Cyclic Redundancy Check CRC Parameter 1 The first parameter is a reference to a variable of integer type or word type which is used to accumulate the result 2 The second parameter is an expression of byte type or char type and is the value to use as the data 3 The third parameter is an expression of integral type and is the value to use as the CRC polynomial If this parameter is not supplied then the default CRC polynomial i e 04C11DB7 is used Example J RRR KR RK KKK KKK kkk k kkk I k k k kk k KK kk k k k k k k k k OK k k k k OK This program uses to calculate the Basically and t
159. cedure Description The gettime procedure retrieves the current system time Parameter 1 The first parameter is a reference to a variable of integer type or word type which will store the current hour 2 The second parameter is a reference to a variable of integer type or word type which will store the current minute 3 The third parameter is a reference to a variable of integer type or word type which will store the current second Example Suppose the current system time is 2 45 05 P M then after gettime hour minute second Portability Operating Systems Al1l Standard Pascal No 7 4 26 The gotoxy procedure Description The gotoxy procedure moves the text mode cursor to a specified x y coordinate on the screen Parameter 1 2 The first parameter is an expression of integral type which specifies the x coordinate to move the cursor to The second parameter is an expression of integral type which specifies the y coordinate to move the cursor to Example gotoxy 1 1 moves the cursor to the top left hand corner of the screen Portability Operating Systems Windows and DOS Standard Pascal No 7 4 27 The halt procedure Description The halt procedure terminates the program and optionally returns an integral value to the program s caller Parameter The halt procedure s only paramter is optional and if supplied is an expression of integral type that is the value returned by the
160. cedures As an extension to Standard Pascal Irie Pascal supports calling functions and procedures in Windows DLLs using the external directive NOTE Only 32 bit DLLs are currently supported A number of include files with declarations for many of the Windows API functions are distributed with Irie Pascal You can use these include files to gain access to many pre written declarations of Windows API functions without having to create your own declarations for these functions In order to write your own declarations for external functions and procedures you need to understand a little bit about the calling convention used by Windows DLLs Windows DLLs support two calling conventions stdeall and cdecl the one most often used is stdeall By default Irie Pascal will assume that the calling convention is stdcall unless cdecl is specified Unfortunately the two calling conventions are not implemented in exactly the same way by all Windows compilers So if you want to call functions and procedures in a DLL you may need to know which compiler was used to create it and also what compiler options were used This document does not describe the various ways different compilers implement the stdcall and cdecl calling conventions Instead what this document does is describe how Irie Pascal implements these conventions Irie Pascal passes parameters from right to left for both the stdeall and cdecl calling conventions Irie Pascal expects the functi
161. char maxint maxword nil oth_r oth w oth x platform dos platform error platform fbsd platform linux platform os2 platform solaris platform solaris sparc platform win32 readmode rsdefault rsdynamic rsforward rskeyset rsstatic sql tc_all sql tc ddl commit sql tc ddl ignore sql_tc_dml sql_tc_none true writemode 4 2 2 appendmode Description appendmode is used with the built in procedure open to specify that the file variable should be opened for writing in such a way that all writes are made at the end of the associated file regardless of calls to the built in procedure seek i e the file should be opened in append mode Example open file variable filename appendmode Portability Operating Systems Al1l Standard Pascal No 4 2 3 dir_bit Description dir_bit can be AND d see and operator bitwise with the mode parameter returned by the built in procedure getfilemode to determine if a file is a directory NOTE Directories are also called folders Example The simple program below asks for a filename and then tests whether the file is a directory program isdirectory input output var s filename mode integer isdir boolean begin write Enter filename readin s s fexpand s getfilemode s mode isdir mode and dir bit lt gt 0 if isdir then writeln s is a directory else writeln s is not a
162. cifier object variable procedure method identifier 10 1 Compatible types Irie Pascal implements the type compatibility rules defined by Standard Pascal ISO IEC 7185 and adds one more rule to support variable length string types The first four rules below are taken from ISO IEC 7185 and the last rule is added to support variable length string types Types T1 and T2 shall be designated compatible if any of the following statements is true 1 T1 and T2 are the same type T1 is a subrange of T2 or T2 is a subrange of T1 or both T1 and T2 are subranges of the same host type 3 Tl and T2 are set types of compatible base types and either both T1 and T2 are designated packed or neither T1 nor T2 is designated packed 4 T1 and T2 are fixed length string types with the same number of components 5 Either T1 is a variable length string type and T2 is a variable length string type or T1 is a variable length string type and T2 is a fixed length string type and the number of components in T2 is less than or equal to the maximum length of T1 or T1 is a variable length string type and T2 is the char type or T2 is a variable length string type and T1 is a fixed length string type and the number of components in T1 is less than or equal to the maximum length of T2 or T2 is a variable length string type and T1 is the char type 10 2 1 What is assignment compatibility Pascal is a strongly typed language which means amoung other thi
163. cket writeln Writing buffer LogMessage OUT buffer buffer buffer CR LF iRet send DataSocket addr buffer length buffer 0 end WriteDataSocket Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 13 2 The sendto function Description The sendto function sends data through a socket and can be used on connection oriented sockets e g stream sockets or connectionless sockets e g datagram sockets The behavior of this function may depend on whether the socket has it s non blocking mode enabled or disabled see dealing with blocking for more information about the non blocking mode of sockets Non blocking mode disabled If the socket has it s non blocking mode disabled and there is no buffer space available within the transport system to store the data to be transmitted then the sendto function will block and wait for buffer space to become available or for the connection to be closed connection oriented sockets only or for the connection to be reset connection oriented sockets only Non blocking mode enabled If the socket has it s non blocking mode enabled then the number of bytes actually sent can be less than the amount you are trying to send depending the availability of buffer space within the transport system to st
164. claration procedure identification procedure block block declarative part statement part declaration group label declaration group constant definition group type definition group variable declaration group function declaration procedure declaration declarative part declaration group function block block function identifier identifier procedure block block procedure identifier identifier 3 1 What are labels Labels are markers which you can place in front of statements so that the statements can be referenced by goto statements Labels can be digit sequences or identifiers In Standard Pascal labels must be digit sequences Leading zeroes are not significant in labels so 009 and 9 are the same label Example J RRR KR RK KK kkk k kkk k kk k k k k k k k k k k k k k k k k k k k k k k k I I k k k k k k k k I k This program counts counts from 1 to 10 using goto J RRR KR kkk kkk kkk kkk k kkk kkk kk kkk k kk k k RK k kkk k k KK RK k k k k k program count output label write_count const minimum 1 maximum 10 var count integer begin count minimum write count writeln count count count 1 if count lt maximum then goto write count end Labels must be declared in a label declaration group before they can be used Syntax NOTE for clarity some parts of the syntax are omitted see Irie Pascal Gr
165. comparision is done If the operands are of char type or of string type then the char string type conversion rules are applied before the comparision is done The result of this operation is of boolean type and is true if the operands are equal and false otherwise Example 23 23 results in true 23 23 results in true 23 23 0 results in true 23 0 23 results in true 23 23 results in false 2 3 results in false 3 2 results in false 8 4 3 3 Is not equal Description The lt gt operator takes two operands and compares them for equality If the operands are numeric then the numeric type conversion rules are applied before the comparision is done If the operands are of char type or of string type then the char string type conversion rules are applied before the comparision is done The result of this operation is of boolean type and is true if the operands are not equal and false otherwise Example 23 lt gt 23 results in false 23 lt gt 23 results in false 23 lt gt 23 0 results in false 23 0 lt gt 23 results in false 23 lt gt 23 results in true 2 lt gt 3 results in true 3 lt gt 2 results in true 8 4 4 1 The relational operators The relational operators are Is less than Is less than or equal Is greater than Is greater than or equal With numeric operands the relational operators compare the values of the operands For operands of st
166. connection open Description The open method procedure of the connection object type is used to open a connection to a database engine Example For example the simple program below illustrates how to call the open method NOTE The actual connection strings you will use in your own programs will probably differ from the one used in the program below program Connect var conn connection begin new conn Create instance of connection object before using it if supported feature odbc then conn open ODBC DSN test user sa password else if supported feature mysql then conn open MYSQL user sa password socket tmp mysql soc Add code here to process database conn close dispose conn Destroy instance of connection object when finished end Parameter The only parameter to this procedure is the connection string which is an expression of type string NOTE Before an attempt is made to actually open a connection the connection string is processed to determine what kind of connection to open and what are the parameters to use for the connection The connection string is processes as follows The connection string must be prefixed by a connection type specifier which is separated from the actual connection string by a semi colon First the connection type specifier is separated from the connection string Next the connection type specifier is compared with ODBC in such
167. contents of the input file to the output file program cat f g var f g text c char begin reset f rewrite g while not eof f do begin Ck fr get f g I C7 put g end close g close f end Portability Operating Systems Al1l Standard Pascal Yes Description 7 4 21 The getdate procedure The getdate procedure retrieves the current system date Parameter 1 The first parameter is a reference to a variable of integer type or word type which will store the year part of the current system date 2 The second parameter is a reference to a variable of integer type or word type which will store the month part 1 to 12 of the current system date 3 The third parameter is a reference to a variable of integer type or word type which will store the day part 1 to 21 of the current system date 4 The fourth parameter is a reference to a variable of integer type or word type which will store the day of the week part 0 to 6 counting from Sunday of the current system date Example Suppose the current system date is Wednesday September 30 1998 then after GetDate year month day day of week year 1998 month 9 day 30 day of week 3 Portability Operating Systems Al1l Standard Pascal No 7 4 22 The getfiledate procedure Description The getfiledate procedure retrieves the modification date of a file Parameter 1 The first parameter is an
168. ctions and procedures is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax function declaration function heading external directive procedure declaration procedure heading external directiv dllname string literal xternal directive external dll dliname name name stdcall cdecl function heading function identifier formal parameter list result type name identifier procedure heading procedure identifier formal parameter list result typ type identifier dilname is a string literal that is the name of the Windows DLL to call name is the name of the function or procedure in the DLL If name is not specified then the name of the function or procedure in the DLL is assumed to be the same as the name of the function or procedure in the declaration stdcall specifies that the stdcall calling convention should be used This is the default cdecl specifies that the cdecl calling convention should be used 2 9 4 3 The forward directive The forward directive specifies that the current function or procedure declaration is incomplete the function or procedure block is omitted Example The following simple example illustrates how to use the forward directive program forward output procedure display message string forward procedure DisplayHello begin display Hello end procedure display
169. cuting a for statement it is best if the value of the control variable is changed only by the for statement If another statement alters the value of a for statement s control variable it usually causes problems in the program In an apparent effort to protect programmers from making that kind of mistake Standard Pascal ISO IEC 7185 defines a number of rules that restrict how control variables are used and Irie Pascal implements these rules The first rule is that control variables must be declared at the same level as the for statement containing them i e if the for statement is in a function or procedure then the control variable must be local to that function or procedure and if the for statement is in the main program block then the control variable must be global Keeping the control variable local makes it easier to control access The second rule is that neither the for statement nor any function or procedure local to the block containing the for statement shall contain a statement that threatens the control variable A statement threatens the control variable if the execution of the statement could possibly alter the value stored in the control variable An assignment statement threatens a control variable if the control variable is the variable being assigned to e A function or procedure call threatens a control variable if the control variable is being passed by reference A read or readin statement threatens a control variable
170. d Portability Operating Systems Al1l Standard Pascal No 7 4 56 The str procedure Description The str procedure converts an integral or real value into a string and stores this string into a string variable Parameters 1 The first parameter specifies up to three items The first item is an expression of integral type or real type and is the value to be converted into a string 2 The second item is optional and if supplied is the minimum width of the string the value is converted to If this item is not supplied then the minimum width of the string depends on the type of the value being converted If an integral value is being converted then the minumum width of the string is eigth 8 characters and if a real value is being converted then the minimum with of the string is nine 9 characters NOTE The string is padded on the left with spaces if it is shorter than the minimum width 3 The third item is optional if a real value is being converted and is the number of digits that follow the decimal point in the converted string the real value is converted into fixed point representation If third item is not supplied and a real value is being converted then the real value is converted into a exponential representation 4 The second parameter is a reference to the string variable that will store the converted string value Example str 1034 s will store i 1034 in s str 1034 1 s will store 103
171. d set type packed file type packed list type object type string type new typ new ordinal type new structured type new pointer typ type denoter type identifier new typ type identifier identifier variable declaration identifier list type denoter 7 1 What are functions and procedures Description Pascal encourages modular programming where a program is created from a number of smaller and simpler pieces known as modules Modules can make call other modules i e execute other modules or even call themselves Pascal supports two kinds of modules which are called functions and procedures Functions are called in expressions and each function call has a value in an expression Procedures on the other hand are called in procedure statements In all other respects functions and procedures are identical and the generic term subroutine will be used to refer to both types of modules Sometimes it is useful to create subroutines that accept input data and or produce output data One way to achieve this to have the subroutines use global variables i e variables declared in the main program block to store the input and output data However the overuse of global variables can make programs difficult to understand and change The basic problem is that since gloval variables are not specific to any particular subroutine it can be difficult to keep track of which subr
172. d procedures that return multiple recordsets Example For example if you open a recordset like so rs open conn EXEC procName and the stored procedure procName returns multiple recordsets then the recordset object will be positioned at the first record of the first recordset The call rs movenext would move to the second record in the first recordset but the call rs moreresults would move to the first record in the second recordset Portability Operating Systems Al1l Standard Pascal No 5 15 21 4 recordset movenext Description The movenext method procedure of the recordset object type is used to move to the next record in the current recordset of an open recordset object Example For example if you have a recordset object reference rs that refers to an open recordset then the following call rs movenext will move to the next record in the recordset Portability Operating Systems Al1l Standard Pascal No 5 15 21 5 recordset open Description The open method procedure of the recordset object type is used to open a recordset In order to call this method you need a recordset object reference a connection object reference to open connection object as well as the SQL statement which will return the recordset or recordsets that will be referenced by the open recordset object Example The code fragment below show a typical use of a recordset NOTE The code fragment is not a comp
173. d variable field designator compound statement begin statement sequence end conditional statement if statement case statement constant sign sign cons character 1l string lite ral finition identifier sign integer number real number tant identifier iteral ntifi r identifier constant de constant de constant id control decimal integer digit sequence declaration group label declaration group constant definition g fFinition group variable decl type de function decl re declaration procedu aration croup aration group constant variable entire variable declarative part declaration group digit 0 L a digit sequence digit digit directive forward directive dllname string literal domain typ else part empty statement empty string entire variable enumerated constant type identifier PP eee else statement T2 1 3 ah S S 7 ety tgt variable identifier identifier fFinition group const constant definition external directive constant definition very enumerated constant list enumerated constant enumerated constant numerat exponent expression shift expression d typ e re numerated constant list Iname name external directive external dl facto
174. data is available from a socket but the SO OOBINLINE socket option is disabled Declaration The system include file WinSock2 ine contains the following declarations for the select function and the fd_set and timeval types FD_SETLAST 63 fd_set packed record fd_count u_int Number of sockets in the array fd_array array 0 FD_SETLAST of SOCKET array of sockets end timeval packed record tv_sec integer seconds tv_usec integer and micro seconds i e 1 1 000 000 of a second end function select nfds integer var readfds writefds exceptfds fd_set var tmeout timeval integer Arguments At least one of the second third or fourth arguments must not be null The First Argument The first argument is provided only for compatiblility with the Berkeley Sockets API and is ignored The Second Argument The second argument to the select function is of type fd_set and is passed by reference When you call the select function this argument should contain the set of sockets you want to check for readability If you don t want to check any sockets for readability then use null as the value of this argument When the select function returns this argument contains the set of sockets that were checked and found to be readable The Third Argument The third argument to the select function is of type fd_set and is passed by reference When you call the select function this argum
175. database changes e g record updates are visible to keyset recordsets after the recordset is opened but others e g record insertions and deletions are not NOTE Irie Pascal does not currently support keyset recordsets if you specify this constant then a dynamic recordset is opened instead unless the database is MySQL in which case a forward only recordset is opened Example rs open conn sSQL rskeyset In the example above rs is the recordset object that will contain the opened recordset conn is the connection object containing an open connection to a database sSQL is a string variable containing the SQL statement that defines the recordset rskeyset specifies that a keyset recordset should be opened Portability Operating Systems Al1l Standard Pascal No 4 2 48 rsstatic Description rsstatic is used when opening a recordset see recordset open to specify that a static recordset should be opened Static recordsets are scrollable i e you can move both forwards and backwards through the records in the recordset Database changes e g record inserts updates and deletions are not visible to static recordsets after the recordset is opened NOTE Irie Pascal does not currently provide a way to move backwards through a recordset so you can not take full advantage of static recordsets Also if the database is MySQL then this constant is ignored and a forward only recordset is opened instead Example rs open conn sSQL r
176. declaration for the gethostname function function gethostname name address namelen integer integer external dll ws2_32 d11 Arguments The First Argument The first argument passed to the gethostname function is the operating system address of the buffer that you supply to store the host name retrieved The type of this argument is the built in type address so you must use the built in function addr to get the operating system address of the buffer The host name that will be put into this buffer by the gethostname function is a null terminated string i e a cstring The Second Argument The second argument passed to the gethostname function is the length of the buffer you supplied to store the host name Return Values The gethostname function returns a value of integer type that indicates whether the call was successful A value of zero means that the call succeeded A value of SOCKET_ERROR indicates that the called failed and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail NOTE The constant SOCKET ERROR is declared in the system include file WinSock2 inc Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 16 2 The getpeername function Description The getpeername function retr
177. directory end Portability Operating Systems Al1l Standard Pascal No 4 2 4 false Description false is the first enumerated constant defined by the built in enumerated type boolean The ordinal value of false is zero Portability Operating Systems Al1l Standard Pascal Yes 4 2 5 feature_calldll calling DLLs supported Description feature_calldll is used with the built in function supported to determine if the current platform supports calling external functions and procedures in DLLs Example if supported feature_ calldll then begin Calling DLLs is supported so go ahead and make the calls end else begin Calling DLLs is not supported so do something else of abort end Portability Operating Systems Al1l Standard Pascal No 4 2 6 feature_closedir closedir supported Description feature_closedir can be used to determine if the current platform supports the built in procedure closedir Example if supported feature closedir and supported feature readdir and supported feature opendir then begin open directory retrieve filenames and then close directory end else begin Opening reading and closing directories is not supported so do something else of abort end Portability Operating Systems Al1l Standard Pascal No 4 2 7 feature_clrscr clrscr supported Description feature_clrscr can be used to determine if the current platfor
178. dition to be false and terminate the execution of the loop Example For example below is a very simple program which illustrates the use of the while statement program ten output var count 2 Tesli begin count 1 while count lt 10 do begin writeln count count count 1 end end Syntax NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax while statement while boolean expression do statement 9 11 For statement Description For statements perform an action in a counting loop i e perform the action for a specified number of times and counts each performance of the action For statements contain the following A variable called the control variable that stores the current loop counter The initial value of the loop counter which is specified by an expression of ordinal type The direction of the loop count specified either by the reserved word to which indicates that the loop counts upwards or by the reserved word downto which indicates that the loop counts downwards The final value of the loop counter which is specified by an expression of ordinal type A statement that specifies the action performed in the counting loop This statement can be a compound statement containing a statement sequence Usually execution of a for statement is as follows 1 The initial value is stored in the control variable The stat
179. e The existing values in the file can not be changed New values can not be added to the file Also the file must already exist when the file variable is opened it s contents are preserved and the current file position is set to the beginning of the file The mode in which a file variable is opened specifies which operations can be performed on the file associated with the file variable and also what happens to the file when the file variable is opened If a file variable is opened in write only mode then operations on the file associated with the file variable are allowed as follow Values can not be retrieved from the file The values in the file can be changed New values can be added to the file Also if the file already exists when the file variable is opened then it s contents are deleted If the file does not already exist when the file variable is opened then it is created and is initially empty The mode in which a file variable is opened specifies which operations can be performed on the file associated with the file variable and also what happens to the file when the file variable is opened If a file variable is opened in read write mode then operations on the file associated with the file variable are allowed as follow Values can be retrieved from the file The values in the file can be changed New values can be added to the file Also if the file already exists when the file variable is opened then it
180. e dispose rs Portability Operating Systems Al1l Standard Pascal No 7 2 32 The isprint function Description The isprint function returns a value of type boolean which indicates whether the parameter passed to it is a printable character If the parameter is a printable character then the value true is returned and if the parameter is not a printable character then the value false is returned Parameter The isprint function s only parameter is an expression of char type Example isprint A returns true isprint 3 returns true isprint returns true isprint returns true isprint chr 10 returns false isprint chr 8 returns false Portability Operating Systems All Standard Pascal No 7 2 33 The isspace function Description The isspace function returns a value of type boolean which indicates whether the parameter passed to it is a whitespace character i e space tab linefeed formfeed or carriage return If the parameter is a whitespace character then the value true is returned and if the parameter is not a whitespace character then the value false is returned Parameter The isspace function s only parameter is an expression of char type Example isspace returns true isspace chr 9 returns true assuming chr 9 is TAB isspace chr 10 returns true assuming chr 10 is LINEFEED isspace chr 13 returns true assuming ch
181. e g close f end Portability Operating Systems Al1 Standard Pascal No 7 4 44 The read procedure Description The read procedure reads values from the file associated with a file variable into one or more variables Parameters 1 The first parameter is optional and if supplied is a reference to the file variable associated with the file to read from If this parameter is not supplied then the read procedure reads values from the file associated with input 2 The other parameters are references to the variables used to store the values read from the file Reading From Text Files If the read procedure reads values from a text file 1 e a file associated with a file variable of type text then the way the values are read is determined by the type of the variable used to store the values Ifa variable of char type or a subrange of char type is being used to store the values read from the text file then a single character is read from the text file and this character is stored without conversion in the variable Ifa variable of string type is being used to store the values read from the text file then characters are read from the text file and stored in the variable until either the end of the line is reached or the number of characters stored in the variable is equal to the maximum number of characters that can be stored in the variable Ifa variable of an integral type or a subrange of an integral type i
182. e the row where the next character written to the screen will be displayed NOTE Screen rows are numbered from one not zero Parameter None Portability Operating Systems Windows and DOS Standard Pascal No 7 3 1 Function declarations Description Function identifiers are identifiers that have been associated with a function using a function declaration Example Here is an example of a function declaration This function checks whether a files exists Actually it really checks to see if a file can be opened for reading without causing an error which is usually the same thing The function first turns off run time error trapping so that if an error occurs it can be retrieved with getlasterror vather than causing the program to halt Then the function attempts to open the file for reading If no errors occur then the file is closed and the file must exist If an error occurs then the function assumes the file does not exist In either cas rror trapping it turned back on before the function exits function FileExists name filename boolean var f text begin FileExists traperrors false reset f name if getlasterror 0 then begin close f FileExists true end else FileExists false traperrors true end FileExists Syntax NOTE for clarity some parts of the synt
183. e the second form where a string expression is used is provided for the cases where the property name is a keyword You can see this in the cdonts example below in which the property named to could not be specified as objMail to since to is a keyword instead this property is specified using the second form like so objMail to The syntax for calling object method functions and procedures is given below function method designator object variable function method identifier actual parameter list procedure method statement procedure method specifier actual parameter list actual parameter expression variable access procedure identifier function identifier actual parameter list actual parameter actual parameter function method identifier identifier object variable variable access procedure method identifier identifier procedure method specifier object variable procedure method identifier 5 14 2 Generic objects Description Generic object types are not any particular object type but are instead any object type associated with an instance of an object created with the built in function createobject Currently createobject can only create instances of COM objects and only those COM objects which support late binding i e the COM objects must export the IDISPATCH interface or in other words the COM objects must be OLE automation servers
184. e Pascal also recognizes comments beginning with in which case the and any text that follows on the same line is ignored So for example the line below is a comment rest of the text on the line By default comments can not be nested i e by default comments can not contain other comments So comments like outer inner comment comment will be terminated at the first close comment marker like below outer inner comment the last part comment will not be treated as part of the comment and will cause a syntax error There is a compiler option that causes the compiler to support nested comments When this compiler option is enabled the compiler recognizes the end of comments only when the number of close comment markers matches the number of open comment markers So the example comment above will terminate only after the second Both open comment markers and are considered to be equivalent and both close comment markers and are considered to be equivalent So when nested comments are not enabled the compiler will not recognize comments like the one below outer inner comment comment Support for nested comments is disabled by default since in Standard Pascal comments do not nest Compiler directives are special kinds of comments and are instructions to the compiler See compiler directives for more information 2 5 Compiler directives Compiler directives are special kinds o
185. e WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 6 1 Creating data sockets Data Sockets In this manual the term data sockets means sockets that you can use to send and receive data The other kind of sockets are listening sockets which you can use to listen for attempts by other sockets to connect When you first create a socket it is a data socket by default In order to create a listening socket you must take some extra steps see creating listening sockets The CreateSocket Function Description The name of the function in the Berkeley and Windows Sockets libraries that creates sockets is socket and the name of the return type of this function is SOCKET Although the two names differ only in case this is not a problem for these libraries because the libraries are designed for the C programming language which is case sensitive In C socket and SOCKET are different identifiers and so there is no conflict between the name of the function and the name of its return type However Pascal is not a case sensitive language so socket and SOCKET are the same identifier and the name of the function would conflict with the name of the return type In order to avoid this conflict the name of the function was changed to CreateSocket Declaration The system include file WinSock2 ine contains the following declaration for the CreateSocket function fu
186. e and operator bitwise with the filemode retrieved by the built in procedure getfilemode to determine if any user belonging to the same group as the owner of a file or directory has permission to read the file or directory Example For example the simple program below asks for a filename and then displays the group permissions for the file program GroupPermissions input output var s filename mode integer isdir boolean begin write Enter filename readin s s fexpand s getfilemode s mode isdir mode and dir bit lt gt 0 write Group permissions if mode and grp r lt gt 0 then write Read if mode and grp_w lt gt 0 then write Write if mode and grp_x lt gt 0 then if isdir then write Search else write Execute writeln end Portability Operating Systems All Standard Pascal No 4 2 25 grp_ w Description grp_w can be AND d see and operator bitwise with the filemode retrieved by the built in procedure getfilemode to determine if any user belonging to the same group as the owner of a file or directory has permission to write to the file or directory Example For example the simple program below asks for a filename and then displays the group permissions for the file program GroupPermissions input output var s filename mode integer isdir boolean begin write Enter filename readin s
187. e boolean expression do statement with statement with record variable list do statement write parameter expression expression expression write parameter list file variable write parameter write parameter writeln parameter list file variable write parameter write parameter The term blank is used in this manual to mean a space tab formfeed or end of line character and the term blanks means a sequence of blank characters A directory variable is a variable of the built in type dir that can be associated with a directory folder on an external storage device in such a way that the names of the files in the directory folder can be read A file is a collection of values of a particular file type that is stored on an external storage device The current file position of a file is the position in the file that the next file operation will occur i e the position of either the next value read from the file or the next value to be changed in the file or the next value added to the file The mode in which a file variable is opened specifies which operations can be performed on the file associated with the file variable and also what happens to the file when the file variable is opened If a file variable is opened in read only mode then operations on the file associated with the file variable are allowed as follow Values can be retrieved from the fil
188. e by the compiler The built in variable identifiers are listed below eoeeoe0e B 6 13 2 errors Description errors is the variable identifier for a built in list variable which stores the list of most recent trappable errors that were detected NOTE This list variable is automatically cleared before each operation that could cause a trappable error so don t expect the list of errors to be maintained indefinately The operations that can cause trappable errors are file and database operations Portability Operating Systems Al11 Standard Pascal No 6 13 3 exitcode Description exitcode is the variable identifier for a built in variable of type integer whose value is returned to the calling program when your program exits Example For example suppose you want to return a value of 1 from your program perhaps to indicate that your program detected an error then you can use the following code exitcode 1 halt NOTE You can treat exitcode like any other integer variable i e you can assign integer values to it use it in an expression pass it as an argument to a function etc Portability Operating Systems Al1l Standard Pascal No 6 13 4 input Description input is the variable identifier for a built in file variable associated with the standard input stream The standard input stream is usually connected to the computer keyboard Portability Operating Systems Al1l Standard Pascal Yes 6 13 5 null
189. e file whose modification date is to be set 2 The second parameter is an expression of integral type that specifies the year part of the file modification date 3 The third parameter is an expression of integral type that specifies the month part 1 to 12 of the file modification date 4 The fourth parameter is an expression of integral typethat specifies the day part 1 to 31 of the file modification date Portability Operating Systems Al1l Standard Pascal No 7 4 54 The setfiletime procedure Description The setfiletime procedure sets the modification time of a file Parameter 1 The first parameter is an expression of string type or char type which is the name of the file whose modification time is to be set 2 The second parameter is an expression of integral type that specifies the hour part of the file modification time 3 The third parameter is an expression of integral type that specifies the minute part of the file modification time 4 The fourth parameter is an expression of integral typethat specifies the second part of the file modification time Portability Operating Systems Al1l Standard Pascal No 7 4 55 The sleep procedure Description The sleep procedure waits for a specified number of seconds to elapse Parameter The sleep procedure s only parameter is an expression of integral type that is the number of seconds to wait Example sleep 1 waits for one 1 secon
190. e formal parameter list of the procedure specified by an actual procedural parameter must be congruent with the formal parameter list of the corresponding formal procedural parameter Standard Pascal takes into account the formal parameter sections when deciding whether two formal parameter lists are congruent and requires that they must have the same number of formal parameter sections amoung other requirements Irie Pascal ignores formal parameter sections and compares individual parameters So for example Irie Pascal considers the following program to be valid but Standard Pascal does not program functional output function Operation function op a b integer integer i j integer integer begin Operation op i j end function Add c integer d integer integer begin Add 3 fd end begin writeln Operation Add 3 1 end The formal parameter list of the function Add contains two formal parameter sections c integer and d integer while the formal parameter list of the formal functional parameter op contains one formal parameter section a b integer and so Standard Pascal does not consider the two formal parameter lists to be congruent and therefore the following Operation Add 3 1 is invalid Irie Pascal compares corresponding formal parameters idividually so c integer is compared with the first parameter in a b integer and they are both value parameters of i
191. e identification procedure block procedure heading procedure block procedure heading procedure identifier formal parameter list procedure identification procedure procedure identifier procedure identifier identifier procedure method identifier identifier procedure method specifier object variable procedure method identifier procedure method statement procedure method specifier actual parameter list procedure parameter specification procedure heading roc dure statement procedure identifier program program heading rite parameter list p actual parameter list read parameter list readln parameter list w program block block l1 writeln parameter list program block program heading program identifier program parameter program parameter list identifier list property designator object variable property specifier property identifier identifi property specifier property identifier property string property string string expression read parameter list file variable variable access readln parameter list file variable variable access real number digit digit reco reco record variabl record variabl l part exponent scale factor t sequence fractional t sequenc xponent scale rd section identifier lis rd type record field l
192. e identifier ield list ixed part fixed part variant part l variant part 1 eI tr ir E fixed part record section record section identifier list identifier identifier new ordinal type enumerated type subrange type new pointer typ A domain type domain type new structured type packed array type packed record type packed file type packed list type object string packed set type type type new type new ordinal type new structured type new pointer typ record section identifier list type denoter tag fi ld identifier tag type ordinal type identifier type denoter type identifier new typ type identifier identifier variant case constant list field list variant body variant list variant part completer variant part completer variant list variant variant variant part case variant selector of variant body variant part completer otherwise else field list variant selector tag field tag type 5 10 Set types Description Set types define values which specify whether individual elements known not suprisingly as set elements are present or not The group of possible set elements of a particular set type form an ordinal type known as the set s base type Set values do n
193. e information 1 2 Compliance statement Irie Pascal complies with the requirements of level 0 of ISO IEC 7185 with the following exceptions Appendix B Deviations from ISO IEC 7185 ISO IEC 7185 is the standard for the Pascal porgramming language published by the Internation Organization for Standardization NOTE Irie Pascal compliance with ISO IEC 7185 has not been formally certified by an external body 2 1 What are language elements Language elemements are the symbols and separators that make up a Irie Pascal program These language elements are Character literals Reserved words Separators Compiler directives Special symbols String literals Integers Real numbers Identifiers 2 2 Character literals Character literals are symbols that represent single characters and can take one of three different forms 1 enclosed by single quotes 2 enclosed by double quotes 3 prefixed by the pound sign Character Literals Enclosed By Single Quotes Character literals can be formed by enclosing the character being represented in single quotes NOTE Single quote characters in character literals enclosed in single quotes are represented by a pair of single quote characters So A represents the character A and tt represents the character Character literals are case sensitive so X is not equal to x NOTE In Standard Pascal ISO IEC 7185 character literals must be enclosed in single quo
194. e length string type called name with a maximum length of 80 use name string 80 or name string 80 To create a variable length string type called phone with a maximum length of 255 use phone string or phone string 255 or phone string 255 In most case it is best to use the built in type string to create variable length string types However variable length string types defined with estring are useful when the values of a variable length string are going to be passed to or from external functions procedures written in the C programming language For example this simple hello world program uses two variables of cstring types to pass values to the Windows API function MessageBox program winhello SI winuser inc const NULL HANDLE 0 CR 13 var csText csCaption cstring RetVal integer begin csText Hello world chr CR Press Cancel when done csCaption Irie Pascal Windows Hello World Program repeat RetVal MessageBox NULL HANDLE addr csText addr csCaption MB OKCANCEL MB ICONEXCLAMATION lt r until RetVal IDCANCEL end Syntax The syntax for defining new variable string types is given below see array types for the sytax for defining new fixed length strings NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax string type pascal string type c string type c
195. e msdos procedure The new procedure The open procedure The opendir procedure The pack procedure The page procedure The popen procedure The put procedure The randomize procedure The rawread procedure The rawwrite procedure The read procedure The readdir procedure The readin procedure The rename procedure The reset procedure The rewinddir procedure The rewrite procedure The rmdir procedure The seek procedure The setfiledate procedure The setfiletime procedure The sleep procedure The str procedure The textbackground procedure The textcolor procedure The traperrors procedure The unpack procedure The val procedure The write procedure The writeln procedure 7 4 2 The append procedure Description The append procedure associates a file variable with a file i e opens the file variable and allows it to be used to manipulate the file The append procedure opens the file variable in append mode The open procedure can also be used to open file variables in append mode Parameters 1 The first parameter is a reference to the file variable to be opened 2 The second parameter is an expression of string type or char type and names the file variable referenced by the first parameter as if the built in procedure assign had been called The name of the file variable referenced by the first parmater controls which file is opened by the append procedure
196. e of integer type is first converted to a value of real type before the addition takes place Irie Pascal automatically performs type conversions on the operands of expressions where necessary by applying one of the following rules The numeric type conversion rules The char string type conversion rules 8 3 2 Numeric type conversion rules Description Irie Pascal applies the numeric type conversion rules when performing an operation with two numeric operands to convert one or both operands to the same type Any operand of a subrange type is first converted to its host type Any operand of byte type or shortint type or shortword type is converted to integer type e If one operand is of integer type and the other operand is of type word then the operand of type integer is converted to type word If one operand is of real type and the other operand is not then the other operand is converted to real type 8 3 3 Char String type conversion rules Description Irie Pascal applies the char string conversion rules when performing an operation with two operands of char type or string type to convert one or both operands to the same type If one operand is of char type and the other operand is of string type then the operand of type char is converted to type string 8 4 1 What are operators Below is a table of all the operators supported by Irie Pascal in order of decreasing precedence All operators on the sa
197. e or directory has permission to read from the file or directory Example For example the simple program below asks for a filename and then displays the file permissions for users who not belong to the same group as the owner of the file program OtherUsersPermissions input output var s filename mode integer isdir boolean begin write Enter filename readin s s fexpand s getfilemode s mode isdir mode and dir bit lt gt 0 write Other permissions f mode and oth_r lt gt 0 then rite Read f mode and oth w lt gt 0 then rite Write f mode and oth _ x lt gt 0 then f isdir then rite Search lse rite Execute riteln end SSO SHEE H Portability Operating Systems Al1l Standard Pascal No 4 2 33 oth_w Description oth_w can be AND d see and operator bitwise with the filemode retrieved by the built in procedure getfilemode to determine whether users not belonging to the same group as the owner of a file or directory has permission to write to the file or directory Example For example the simple program below asks for a filename and then displays the file permissions for users who not belong to the same group as the owner of the file program OtherUsersPermissions input output var s filename mode integer isdir boolean begin write Enter filename readin s s fexpand s getfilemode s
198. e that were used to create them Example Here is a simple example program that generates some random numbers stores them in a list sorts the numbers and then prints the numbers out program sort output const max 20 var numbers list of integer procedure GenerateRandomNumbers var io 1 max begin for i 1 to max do insert random 100 1 numbers end procedure SortNumbers var i s 1 max swapped boolean temp integer begin repeat swapped false for i 1 to max 1 do if numbers i gt numbers i 1 then begin temp numbers i numbers i numbers i 1 numbers i 1 temp swapped true end until not swapped end procedure PrintNumbers var 1 3 Lssmax begin for i 1 to max do writeln i numbers i end begin randomize new numbers GenerateRandomNumbers SortNumbers PrintNumbers dispose numbers end Syntax The syntax for referencing selected variables is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax selected variable list variable index expression index expression index expression expression where list variable is a reference to a list variable and index expression is an expression of integral type that evaluates to the position of a selected variable in the list 6 8 Object variables Description Object variables are
199. e value returned by this function is always integer and is one of the platform constants Parameter None Example For example the program below uses the platform function to display the name of the platform it s running on program ShowPlatform output begin case platform of platform dos writeln DOS platform_os2 writeln 0S 2 platform _win32 writeln Windows platform linux writeln Linux platform fbsd writeln FreeBSD platform solaris writeln Solaris x86 platform solaris sparc writeln Solaris Sparc platform error writeln Unknown Platform end end Portability Operating Systems Al1l Standard Pascal No 7 2 48 The pos function Description The pos function accepts up to three of the parameters described below the last parameter is optional searches for one string in another string and returns the position of the first string in the second string or zero if the first string was not found in the second string Parameter 1 The first parameter needle is an expression of string type or char type and is the string to search for 2 The second parameter haystack is an expression of string type or char type and is the string to be searched 3 The third parameter start is an expression of integral type and specifies the position in haystack to begin searching for needle If start is omitted then haystack is searched starting
200. e which describes a trappable run time error The error type is defined as follows error record number integer name string 16 description string 255 end where number is a numeric error code and uniquely identifies the error name is an alphnumeric error code not all errors have a name description is text describing the error When a trappable error occurs it is placed in an error record and the record is appended to the built in list variable errors Portability Operating Systems All Standard Pascal No 5 15 10 filename type Description filename is the type identifier for a built in string type which is the recommended type for variables used to store file and directory folder names Example Below is a simple program that lists the names of all the files in the current directory and uses variables of type filename to store the names of the files program listfiles output var d dir filename string function IsDir name filename var mode integer begin getfilemode name mode IsDir mode and dir bit lt gt end begin opendir d Open curren repeat readdir d filename if the next file exists and i if filename lt gt and not Is writeln filename until filename closedir d Close directory end Portability Operating Systems Al1 Standard Pascal No boolean 0 t directory Get next file in direct
201. eate instances of generic object type since generic object type do not describe what an object instance looks like new wouldn t know how much memory to allocate The built in function createobject can be used to create an instance of a generic object type and returns the value identifying the instance The value returned by createobject is usually stored in a generic object reference NOTE The built in function createobject can not currently be used to create an instance of any of the built in object types The built in procedure dispose should be used to destroy instances of the built in object types created with new when you have finished using the instances This also removes the value identifying the destroyed instance from the collection of values defined by the built in object type The built in procedure dispose should also be used to destroy instances of generic objects created with createobject This also removes the value identifying the destroyed instance from the collection of values defined by the generic object type Example For example the simple program below illustrates how to use the built in procedures new and dispose with object types program Data input output var conn connection procedure DisplayError msg string begin writeln ERROR msg halt end function GetConnectionString string var S sSDSN sSUSER sPassword string function GetStringValue sPrompt string
202. eatures Below are links to definitions of how Irie Pascal handles implementation defined features Each definition has the following format First the official description of the feature is taken from ISO IEC 7185 and displayed in red This is followed by a simplified description if the official description is unclear or requires the reader to have a copy of ISO IEC 7185 Finally a statement describing how Irie Pascal handles the feature is at the end String elements Provision of tokens and delimiting characters Size and precision of real values Character set Ordinal values of characters Characters prohibited from text files When I O is performed Value of maxint Accuracy of real operations and functions Default value of TotalWidth for integer type Default value of TotalWidth for real type Default value of TotalWidth for boolean type Number of digits written in exponents Use of e or E as exponent character on output Case of characters used on output of boolean values Effect of built in procedure page Binding of file type program parameters Effect of reset and rewrite on input and output 16 2 String elements 6 1 7 There shall be an implementation defined one to one correspondence between the set of alternatives from which string elements are drawn and a subset of the values of the required char type In other words the characters that form string literals and character literals is i
203. ecord variable is a reference to the entire record as a unit and can be used to both store record values into and retreive record values from the record variable Each field in a record is stored in a seperate component of the record and can be referenced individually in order to store values into and retrieve values from specific fields A reference to an individual field in a record is called a field designator Field designators usually consist of a reference to the record variable followed by a period and then finally followed by a field specifier which is what the name of the field is called when used in this way Within the statement part of a with statement field designators can consist of just a field designator identifier which is what the name of the field is called when used in this way The record variable is referenced once in the record variable list part of the with statement This can be useful when the statement part of a with statement contains many references to the fields of a record Syntax The syntax for field designators is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax field designator record variable field specifier field designator identifier field designator identifier identifier field identifier identifier field specifier field identifier record variable variable access where record
204. ecordset see recordset open to specify that the default type of recordset should be opened If you are connected to a database with ODBC or if you are connected to a MySQL database then a forward type recordset is opened Example rs open conn sSQL rsdefault In the example above rs is the recordset object that will contain the opened recordset conn is the connection object containing an open connection to a database sSQL is a string variable containing the SQL statement that defines the recordset rsdefault specifies that the default type of recordset should be opened Portability Operating Systems All Standard Pascal No 4 2 45 rsdynamic Description rsdynmic is used when opening a recordset see recordset open to specify that a dynamic recordset should be opened Dynamic recordsets are scrollable i e you can move both forwards and backwards through the records in the recordset Database changes i e record insertions updates or deletions are visible to dynamic recordsets even after the recordset is opened NOTE Irie Pascal does not currently provide a way to move backwards through a recordset so you can t take maximum advantage of dynamic recordsets Also if the you are connected to a MySQL database then this constant is ignored and a forward only recordset is opened instead Example rs open conn sSQL rsdynamic In the example above rs is the recordset object that will contain the opened recordset conn is the
205. ediately with zero bytes received If the connection has been reset the recv function will return SOCKET ERROR and if you then call the WSAGetLastError function to find out the reason for the failure the error code returned will be WSAECONNRESET NOTE The constants VWSAECONNRESET and SOCKET ERROR are declared in the system include file WinSock2 inc Connectionless Sockets When the recv function is used on connectionless sockets it will read the first datagram waiting to be read If the first datagram waiting to be read is larger than the buffer you supply then only the first part of the datagram will be read enough to fill the buffer and the recv function call will return SOCKET ERROR as if the call failed and if you then call the WSAGetLastError function the error code returned will be WSAEMSGSIZE For unreliable protocols for example UDP the unread part of the datagram will be lost For reliable protocols the entire datagram is retained until it is successfully read by calling the recv function with a large enough buffer Before using the reev function on connectionless sockets the connect function must be called to specify the name of the source socket or sockets from which datagrams will be read The reev function will silently discard datagrams from all sockets except the source socket or sockets Declaration The system include file WinSock2 ine contains the following declaration for the reev function function recv s SOC
206. eference to the string variable which will store the name part of the filename If this parameter is not supplied then the name part of the filename is not stored 4 The fourth parameter is optional and if supplied is a reference to the string variable which will store the extension part of the filename If this parameter is not supplied then the extension part of the filename is not stored Although the second third and fourth parameters are optional at least one of them must be supplied Example fsplit usr local bin readme txt d n e stores usr local bin in d and readme in n and Text sun es fsplit c autoexec bat d stores c in d Portability Operating Systems Al1l Standard Pascal No 7 4 20 The get procedure Description The get procedure reads the next component from a file into the file s buffer variable NOTE This procedure is seldom used since it is usually easier to use the read or readln procedures Parameter The get procedure s only parameter is a reference to the file variable associated with the file to be read The file variable must be open before calling this function Example J RRR KR RK KKK RK kkk k kkk k k k k k k k k k k k k k k k k k k k k k k k A k k k k k I k k This program is similar to the unix shell command cat It uses the built in procedures get and put as well as the file buffer s associated with the input and output file to copy the
207. egin handle the error end Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 11 1 The connect function Description The action performed by the connect function depends on whether it is used on connection oriented sockets e g stream sockets or connectionless sockets e g datagram sockets Connection Oriented Sockets When the connect function is used on a connection oriented socket it uses that socket to send a connection request to a listening socket which is listening for connection requests see the listen function for more information about listening sockets What happens next depends on whether the socket sending the connection request has it s non blocking mode enabled or disabled see dealing with blocking for more information about the non blocking mode of sockets Non blocking mode disabled If the requesting socket has it s non blocking mode disabled then the connect function will block and wait for the connection request to either be accepted or be rejected or to fail because of an error Non blocking mode enabled If the requesting socket has it s non blocking mode enabled then the connect function will return SOCKET ERROR immediately as if the call failed however the connection request is still pending and if you then call the WSAGetLastError funct
208. egtype type shortint type shortword type single type text type word type 5 15 2 address type Description address is the type identifier for a built in type whose values are operating system addresses Irie Pascal usually generates and uses virtual machine addresses which are not meaningful to external functions procedures When passing a variable by reference to an external function procedure Irie Pascal will automatically convert the address of the variable from a virtual machine address to an operating system address This automatic conversion is usually enough to allow you to call external functions procedures However in some cases additional work is necessary for example when the external function procedure expects to pass operating system addresses back to you or accepts parameters whose type can vary In those cases it may be necessary to declare the variable or the component of the variable that will contain the operating system address to be of type address Portability Operating Systems All Standard Pascal No 5 15 3 binary type Description binary is the type identifier for a built in file type which does not have a component type i e an untyped file type Normally files can only contain values of the same type which is called the file s component type however this restriction does not apply to untyped file types Values of almost any type can be written to and read from untyped file types Also because
209. eing written should be terminated by an end of line In effect this means that after a text file is closed the last line must be terminated by an end of line Irie Pascal does not automatically terminate the last line in a text file 14 4 new p cl cN Standard Pascal requires support for a form of the required procedure new as follows new p cl cN where p is a pointer to a variant record and c1 thru cN are case constants which correspond to the variants in p Irie Pascal does not currently support this form of new 14 5 dispose q k1 kM Standard Pascal requires support for a form of the required procedure dispose as follows dispose q k1 kM where q is a pointer to a variant record and k1 thru kM are case constants which correspond to the variants in q Irie Pascal does not currently support this form of dispose 14 6 dispose pointer value In Standard Pascal the parameter passed to the dispose procedure is an expression of pointer type However in Irie Pascal the parameter passed to the dispose procedure is a reference to a pointer variable 14 7 Carriage returns Standard Pascal requires that all characters written to a file should appear when the file is read the exception to this is that implementations are allowed to designate a set of characters as prohibited from text files and treat these characters specially The Windows edition of Irie Pascal does not comply fully with this requirement since with this edi
210. ement statement sequence statement statement type identifier identifier value parameter specification identifier list type identifier variable parameter specification var identifier list type identifier 7 2 1 The built in functions The built in functions are functions which are automatically declared by the compiler and each built in function is associated with a built in function identifier Unlike reserved words you can declare your own identifiers with the same spelling as a built in function identifier and if you do so then your declaration will override the declaration made by the compiler The built in function identifiers are listed below getenv getlasterror hex int ioresult isalpha isalphanum isdigit islower isnull isprint isspace isupper isxdigit keypressed length In log locase lowercase odd ord paramcount paramstr e platform trunc unixplatform upcase uppercase urldecode version wait wherex wherey 7 2 2 The abs function Description The abs function returns the absolute value i e the magnitude of the parameter passed to it The type of the value returned by this function is always the same as the type of it s parameter Parameter The abs function s only parameter is the numeric expression i e an expression of integral type or of real type whose absolute value is to be returned Example abs 10 returns 10
211. ement contained in the for statement is executed 3 Ifthe value stored in the control variable is equal to the final value then execution of the for statement is terminated 4 The value stored in the control variable is incremented by one in loops counting upwards or decremented by one in loops counting downwards 5 Execution of the for statement continues with step 2 However the following situations can affect the execution of a for statement Ifthe statement contained in the for statement transfers program execution to a statement outside of the for statement then execution of the for statement is terminated when program execution is transfered The for statement s counting loop can specify that the action be performed zero times in which case no value is stored in the control variable and the statement contained in the for statement is not executed This situation occurs when either the initial value is greater than the final value in loops counting upwards or the initial value is less than the final value in loops counting downwards in either case the initial value and the final value are evaluated and compared but no other action is performed by the for statement before it s execution is terminated You should not depend on the control variable having any particular value after the execution of a for statement is terminated unless program execution was transfered out of the for statement by a goto statement Normally when exe
212. encing nil pointers Official Description 6 5 4 It is an error if the pointer variable of an identified variable denotes a nil value Simplified Description In other words it is an error to dereference a pointer variable which is equal to nil i e p is an error if p nil Error Handling This error is always reported 18 5 Dereferencing undefined pointers Official Description 6 5 4 It is an error if the pointer variable of an identified variable is undefined Simplified Description In other words it is an error to dereference a pointer variable which is undefined i e p is an error if p is undefined Error Handling This error is always reported 18 6 Dangling pointers Official Description 6 5 4 It is an error to remove from its pointer type the identifying value of an identified variable when a reference to the identified variable exists Simplified Description In other words it is an error to use dispose to free the memory allocated for a pointer if other pointers to the same memory exist Error Handling This error is never reported 18 7 Altering file variables Official Description 6 5 5 It is an error to alter the value of a file variable f when a reference to the buffer variable f exists Simplified Description According to ISO IEC 7185 there are four ways of establishing a reference to a variable 1 Passing the variable by reference establishes a reference to the variable for the life
213. ent should contain the set of sockets you want to check for writeability If you don t want to check any sockets for writeability then use null as the value of this argument When the select function returns this argument contains the set of sockets that were checked and found to be writeable The Fourth Argument The fourth argument to the select function is of type fd_set and is passed by reference When you call the select function this argument should contain the set of sockets you want to check for errors If you don t want to check any sockets for errors then use null as the value of this argument When the select function returns this argument contains the set of sockets that were checked and found to have experienced errors The Fifth Argument The fifth argument to the select function is of type timeval and although it is passed by reference it is not modified by the call This argument specifies the maximum length of time the select function should wait for one or more of checks on the sockets to succeed If this argument is null then the select function will wait indefinitely Return Values The select function returns the total number of sockets returned in the second third and fourth arguments is the call is successful If the call fails then the value SOCKET ERROR is returned and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail NOTE SOCKET ERROR i
214. er types record types address double single and real For both calling conventions Irie Pascal supports passing variables of the following types by reference array types ordinal types pointer types record types string types address double single and real Irie Pascal does not yet support passing functions or procedures using either calling convention In order to successfully call external functions and procedures you may need to understand a little bit about how values of the Irie Pascal types are stored Below is a brief description of the what values of the Irie Pascal types are stored First the simple types byte unsigned 8 bit value char unigned 8 bit value double 64 bit floating point value see ANSI IEC std 754 1985 enumerated including boolean signed 32 bit value integer signed 32 bit value real 64 bit floating point value see ANSI IEC std 754 1985 shortint signed 16 bit value shortword unsigned 16 bit value single 32 bit floating point value see ANSI IEC std 754 1985 word unsigned 32 bit value subrange subrange types are stored like their host types e g subranges of char are stored like chars and subranges of integer are stored like integers Next the complex types array These are contiguous sequences of the elements For example array 1 4 of integer is simply a sequence of 4 integers with no gaps in between Multi demensional arrays are trea
215. es the first command line argument in2 accesses the second command line argument out accesses the third command line argument output does not access a command line argument PAD Since output does not access a command line argument it can appear in any position not just the last position without changing which command line arguments are accessed by the other program parameters In other words all of the following are equivalent program append output inl in2 out and program append inl output in2 out and program append inl in2 output out and program append inl in2 out output The second thing to notice about the program are the following lines var inl char files first input file in2 char files second input file out char files output file Here the program parameters except for output appear in variable declarations in the main program block as required They are declared to be variables of type char_file which has been declared to be file of char Now since they are declared to be file variables it means that the command line arguments accessed specify the initial names of the file variables The final thing to notice about the program are the following lines if paramcount lt gt 3 then syntax These lines cause the procedure syntax to be called if the number of command line arguments is not 3 These lines are intended to prevent problems if the user does
216. eset connection oriented sockets only Non blocking mode enabled If the socket has it s non blocking mode enabled and there is no data available to be read from the socket then the reevfrom function will return SOCKET ERROR immediately as if the call failed and if you then call the WSAGetLastError function to find out the reason for the failure the error code returned will be WSAEWOULDBLOCK You can then use the select function to find out when data becomes available to be read from the socket NOTE The constants WSAEWOULDBLOCK and SOCKET ERROR are declared in the system include file WinSock2 inc Connection Oriented Sockets When the reevfrom function is used on connection oriented sockets it will read all of the data waiting to be read up to the size of the buffer you supply If the reevfrom function is used on a socket that has been configured for in line reception of OOB data and there is OOB data waiting to be read then only the OOB data will be read Your program can use the ioctlsocket to determine whether there is OOB data waiting to be read If the socket at the other end of the connection has shut down the connection gracefully and all of the data sent has been received the reevfrom function will return immediately with zero bytes received If the connection has been reset the recvfrom function will return SOCKET ERROR and if you then call the WSAGetLastError function to find out the reason for the failure the error code
217. esides in memory that is allocated by Windows Sockets Your program The application should not make any assumptions about the way in which the memory is allocated The data in the buffer is guaranteed to be valid until the next Windows Sockets function call within the same thread You should copy the null terminated string from the buffer before calling any other Windows Sockets functions Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 16 9 The ntohl function Description The ntohl function converts a value of type u_ ong from TCP IP network byte order which is big endian to host order Declaration The system include file WinSock2 ine contains the following declarations for the u_long type and the ntohl function u_long word function ntohl netlong u_long u_long external dll ws2_32 dl11 Arguments The only argument passed to the ntohl function is the u_ ong value that you want to convert to host byte order Return Values The ntohl function returns the u_ ong value in host byte order Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 16 10 The ntohs function Description The ntohs functio
218. ess parameter specifies that compression is to be used when communicating with the MySQL database server If the mysql compress parameter is not specified then compression is not used Portability Operating Systems All Standard Pascal No 5 15 20 5 connection selectdatabase Description The selectdatabase method procedure is used to make a particular database the default database for an open connection NOTE If you want to retrieve the name of the current database for a connection use the connection databasename property Example For example if conn is a connection object reference with an open connection to a database engine then the following conn selectdatabase test will make test the default database for the connection Portability Operating Systems Al1l Standard Pascal No 5 15 20 6 connection databasename Description The databasename property of the connection object type contains the name of the default database for the connection databasename is a read only property of type string NOTE If you want to change the current default database for a connection call the connection selectdatabase method Example For example if conn is a connection object reference with an open connection to a database engine then the following conn databasename is equal to the default database for the connection referenced by conn Portability Operating Systems Al1l Standard Pascal No 5 15 20 7 connect
219. et open 5 15 21 6 recordset ecof 5 15 21 7 recordset field 5 16 User Defined Type Identifiers 5 16 1 Type definitions 6 Variables 6 1 What are variables 6 2 Named variables 6 3 Anonymous variables 6 4 Array variables 6 5 Buffer variables 6 6 File variables 6 7 List variables 6 8 Object variables 6 9 Pointer variables 6 10 Record variables 6 11 Set variables 6 12 String variables 6 13 Built in Variable Identifiers 6 13 1 The built in variable identifiers 6 13 2 errors 6 13 3 exitcode 6 13 4 input 6 13 5 null 6 13 6 output 6 14 User Declared Variable Identifiers 6 14 1 Variable Declarations 7 Functions And Procedures 1 What are functions and pr res 7 2 Built in Functions 7 2 1 The built in functions 7 2 2 The abs function 7 2 3 The addr function 1 2 4 The arctan function 7 2 5 The chr function 7 2 6 The concat function 7 2 7 The copy function 7 2 8 The copyword function 1 2 9 The cos function 7 2 10 The cosh function 7 2 11 The countwords function 7 2 12 The createobject function 7 2 13 The dirsep function 7 2 14 The eof function 7 2 15 The eoln function 7 2 16 The exp function 7 2 17 The fexpand function 7 2 18 The filematch function 1 2 19 The filepos function 7 2 20 The filesize function 7 2 21 The frac function 7 2 22 The getenv function 7 2 23 The getlasterror function 7 2 24 The hex function 1 2 2
220. eter The randomize procedure s only parameter is optional and if supplied is an expression of integral type that is the seed used to initialize the random number generator If this parameter is not supplied then the random number generator is initialized with a seed derived from the current system date and time Specifying this parameter is useful if you want a repeatable sequence of random numbers Or you can just not call the randomize at all in which case the the random number generator generates the same sequence of the random numbers every time your program is run Example The following program generates two random sequences of numbers The first sequence repeats every time the program is run since the random number generated is initialed with the same seed each time the program is run The second sequence does not repeat since the random number generator is initialized with a system generated seed each time the program is run program rnd output var i integer begin writeln Repeatable sequence randomize 6566 for i 1 to 10 do writeln random 10 writeln Non repeatable sequence Y f wW andomize or L 1 to T0 do riteln random 10 end Portability Operating Systems Al1l Standard Pascal No 7 4 42 The rawread procedure Description The rawread procedure reads up to a specified number of characters from a file into a character buffer The actual number of characters read
221. eturned Example frac 7 234 returns 0 234 Portability Operating Systems All Standard Pascal No 7 2 22 The getenv function Description The getenv function returns the value of an environment variable The type of the value returned by this function is always string Parameter The getenv function s only parameter is the expression of string type or char type which contains the name of the environment variable whose value is to be returned NOTE If no environment variable has a name matching this parameter then an empty string is returned Portability Operating Systems Al1l Standard Pascal No 7 2 23 The getlasterror function Description The getlasterror function returns the number of the last trappable error that occured The type of the value returned by this function is always integer When error trapping is enabled your program automatically checks for trappable errors after each operation that could cause a trappable error Your program will terminate if a trappable error occurs If you do not want this default behavior you can disable error trapping using the built in procedure traperrors and call the getlasterror function to determine if any errors occurred After this function is called the error number is cleared to zero this prevents the function from returning the same error more than once However because of this if you need to refer to the error number more than once you should store the result of the fi
222. eving values from a file you should disassociate the file from the file variable NOTE This process is sometimes referred to as closing the file See close It is not necessary to close files if the program is about to terminate Although files are stored on external storage devices the operating system will usually temporarily store portions of open files in memory to speed up access However this means that changes made to files can be lost if the program crashes If you want to make sure that the changes made to a file are stored on an external storage device then use the built in procedure flush Example Here are some examples of file types file of integer file of char Syntax The syntax for defining new file types is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax file type file of component type component typ type denoter domain typ type identifier new ordinal type enumerated type subrange type new pointer typ A domain type domain type new structured type packed array type packed record type packed set type packed file type packed list type object type string type new type new ordinal type new structured type new pointer typ type denoter type identifier new typ type identifier identifier 5 5 Integral types Description The in
223. expression of string type or char type which is the name of the file whose modification date is to be retrieved 2 The second parameter is a reference to a variable of integer type or word type which will store the year part of the date the file was last modified 3 The third parameter is a reference to a variable of integer type or word type which will store the month part 1 to 12 of the date the file was last modified 4 The fourth parameter is a reference to a variable of integer type or word type which will store the day part 1 to 31 of the date the file was last modified Example Suppose the file c irie readme txt was last modified on Wednesday September 30 1998 then after getfiledate c irie readme txt year month day year 1998 month 9 day 30 Portability Operating Systems All Standard Pascal No 7 4 23 The getfilemode procedure Description The getfilemode procedure retrieves the permission mode of a file The permission mode can be AND d with the permission constants to determine the permissions of the file Parameter 1 The first parameter is an expression of string type or char type which is the name of the file whose permission mode is to be retrieved 2 The second parameter is a reference to a variable of integer type or word type which will store the permission mode of the file Example J KK HK HK KK KKK KKK KKK KKK KK KK KKK KK K A K K K K A A A A a a A K K K K K k a
224. f comments that give instructions to the compiler and look like this OPEN_COMMENT NAME INFORMATION CLOSE COMMENT where OPEN_COMMENT is either or and CLOSE_COMMENT is either or and NAME is the name of the compiler directive and is on of the following B A flag directive that controls short circuit evaluation See Order of evaluation of operands of dyadic operators for more information about short circuit evaluation See also the sc compiler option for the command line compiler for more information documented in the User s Manual I Botha flag directive that controls run time I O checking and a value directive that specifies the name of a file to include See traperrors procedure for more information P A flag directive that controls mandatory parenthesis mode See the p compiler option for the command line compiler for more information documented in the User s Manual R A flag directive that controls range checking See the r compiler option for the command line compiler for more information documented in the User s Manual S A flag directive that controls strict checking of string parameters passed by reference See the s compiler option for the command line compiler for more information documented in the User s Manual U A flag directive that controls checking for accessing undefined values See the u compiler option for the command line compiler for more information documented in the U
225. f contiguous characters seperated by another group of characters called deliminators Parameters 1 The first parameter S is an expression of type string or type char and contains the words to be counted 2 The second parameter D is an expression of type string or type char and contains the delimintors used to seperate words If D is not present then the default deliminators 1 e SPACE TAB RETURN and LINEFEED are used Example countwords example returns 1 countwords this is an example returns 4 Portability Operating Systems All Standard Pascal No 7 2 12 The createobject function Description The createobject function creates an instance variable of the generic object type i e an instance of the generic object type and returns a value that identifies the instance variable Parameter The createobject function s only parameter is an expression of string type or char type which is the name of the COM object class to create an instance of Portability Operating Systems All Standard Pascal No 7 2 13 The dirsep function Description The dirsep function returns a value of type string that is equal to the directory separator character for the current platform NOTE On Windows the value returned is and on Linux FreeBSD Solaris x86 and Solaris Sparc the value returned is Parameters None Portability Operating Systems Al1l Standard Pascal No 7 2 14 The eof function
226. file program append inl in2 out output type char file file of char var inl char files first input file in2 char files second input file out char files output file RRA RRA KKK KKK KKK KK KEK KKK KKK KKK KKK KK KK KKK KKK KKK KKK KKK KKK KKK KKK KK PURPOSE Writes copies the contents of one file into another ARGUMENT KK f the input file EK g the output file NOTES It is up to the caller to open and close the files z procedure WriteFile var f g char file var 3 char begin while not eof f do begin read f c write g c end end FERRER RRE RRRA Ek KKK KKK KKK KKK KKK KKK KKK KKK KKK KK PURPOSE Writes a help screen and then halts gt procedure syntax begin writeln Appends two files together and writes the output to a third file writeln Syntax writeln ivm append inl in2 out writeln where inl is the first input file writeln and in2 is the second input file writeln and out is the output file halt end begin if paramcount lt gt 3 then syntax rewrite out reset inl WriteFile inl out close inl reset in2 WriteFile in2 out close in2 close out end The first thing to notice about this program is the line below program append inl in2 out output Here four program parameters are being used inl access
227. first constant in the range and the last constant in the range separated by as follows first lt Last You could use the constant range to specify the following case constants For example suppose c is a variable of char type and you want to use a case statement to write the word Letter if c contains a letter and the word Digit if c contains a digit then you could specify each case constant individually as follows case c of Vail a oma Val io ae nt Tot i oer ugly VAY B Oty iD y NY VOY PPT 0 5 write Letter Oty ry 2y Les ee TAN VB bol ar aa 8t Toi write Digit end j SEG Ny hes ue J g ery ELE m Vs Mets Vat Uae tS w a Ds y tg h TET Gl VAY ae TOS RY L y M 7 VS 5 ET Eg EVT SWS x Yta rI Or you could use constant ranges like the following case c of atea TAY TA Toia TY write Letter ror 4 hoe write Digit end Constant ranges can be used in case statement like in the example above and in variant record types 13 4 Allow otherwise When the allow otherwise extension is enabled Irie Pascal allows you to use the reserved words otherwise or else in case statements and variant record types to specify all case constants that haven t already been specified For example in the following variant record type character record case c char of trafoa taty TA ra A vowel Boolean ror a TOA value integer otherw
228. from position one If start is greater than the length of haystack then zero is returned Example pos to Hello world returns 5 pos to Hello world 1 returns 5 pos to Hello world 6 returns 8 pos to Hello world 9 returns 0 Portability Operating Systems Al1l Standard Pascal No 7 2 49 The pred function Description The pred returns the ordinal value that is the predecessor of the parameter passed to it It is an error if the parameter does not have a predecessor The type of the value returned by this function is always the same as the The type of the parameter Parameter The pred function s only parameter is an expression of ordinal type Example pred true returns false pred 21 returns 20 pred A returns assuming the ASCII or ANSI character set Portability Operating Systems Al1l Standard Pascal Yes 7 2 50 The ptr function Description The ptr function converts an operating system address into a virtual machine address The type of the value returned by this function is always a generic pointer type which is compatible with all other pointer types Parameter The ptr function s only parameter is an expression of integral type or address type Portability Operating Systems Al1l Standard Pascal No 7 2 51 The random function Description The random function returns a random number The type of the value returned by this function is eithe
229. gned integer subtraction is performed and the result is a value of address type Example Here are some examples using the operator to perform subtraction 5which results in the integer value 2 5 0which results in the real value 2 0 5which results in the real value 2 0 5 Q0which results in the real value 2 0 Oo w w ww o 8 4 2 5 Unary minus Description When the operator has only one operand of integral type or real type it performs unary minus which is the same as subtracting the operand from zero 8 4 2 6 multiplication Description When the operator has two operands of integral type or real type it performs multiplication according to the following rules First the numeric type conversion rules are applied After applying the numeric type conversion rules the operands are either both of integer type or both of word type or both of real type e If both operands are of integer type then integer multiplication is performed and the result is a value of integer type If both operands are of word type then integer multiplication is performed and the result is a value of word type e If both operands are of real type then real multiplication is performed and the result is a value of real type Example Here are some examples using the operator to perform multiplication Swhich results in the integer value 15 5 0which results in the real value 15 0 0 5
230. groups Example Here is an example of a type definition group type symbols record name string value integer end SymbolTable list of symbols color red green blue cardinal 0 maxint IntegerList array 1 100 of integer characters set of char GenericObject object Syntax The syntax for type definition groups is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax type definition group type type definition type definition domain typ type identifier new ordinal type enumerated type subrange type new pointer typ A domain type domain type new structured type packed array type packed record type packed set type packed file type packed list type object type string type new typ new ordinal type new structured type new pointer typ type definition identifier type denoter type denoter type identifier new typ type identifier identifier 6 1 What are variables Description A variable is made up of one or more contiguous memory locations and is used to store values of a particular type It is a common shorthand to refer to the type of the values that can be stored in a variable as the variable s type The number of contiguous memory locations that make up a variable also called the variable s size wil
231. he end then all characters in S starting from P to the end are returned Example copy Testing 5 2 returns in copy Testing 7 returns Lasep copy Testing 1 1000 returns Testing copy Testing 50 returns me Portability Operating Systems Al1l Standard Pascal No 7 2 8 The copyword function Description The copyword function accepts up to three of the parameters described below the last parameter is optional and returns a value of type string which is formed by copying a word from the first parameter NOTE In this help topic the term word is used to mean a group of contiguous characters seperated by another group of characters called deliminators Parameters 1 The first parameter S is an expression of type string or type char and contains the words to be copied 2 The second parameter I is an expression of integral type and specifies the word to copy Words are numbered starting from one so it is an error if I is less than one If I is greater than the number of words in S then no word is copied 3 The third parameter D is an expression of type string or type char and contains the delimintors used to seperate words If D is not present then the default deliminators i e SPACE TAB RETURN and LINEFEED are used Example copyword copyword copyword 1 1 1 copyword Here are some examples using copyword 1234 copyword 1234 copyword 1234 example
232. he loop Example For example below is a very simple program which illustrates the use of the repeat statement program ten output var count s Iratz begin count 1 repeat writeln count count count 1 until count gt 10 end Syntax NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax repeat statement repeat statement sequence until boolean expression statement sequence statement statement 9 10 While statement Description While statements perform an action in a conditional loop as long as the loop condition is true and include the following The loop condition which is specified by an expression of boolean type Before each iteration of the loop the loop condition is evaluated and if it s value is true the loop continues but if it s value is false the loop terminates A statement that specifies the action performed in the loop This statement can be a compound statement containing a statement sequence If this statement transfers program execution to a statement outside of the while statement then execution of the while statement is terminated when program execution is transfered NOTE The loop condition is evaluated before the statement in the while statement is executed so this statement may never be executed Usually the statement in the while statement will perform some action that will eventually cause the loop con
233. he packed array is less then the number of elements in the packed array since values must be copied to all the elements in the packed array NOTE This parameter must be assignment compatible with the index type of the unpacked array The third parameter is a reference to the packed array variable that contains the array elements to be copied into Example Suppose you have the following arrays p packed array 21 23 of integer u array 1 10 of integer then pack u 1 p copies elements to 3 of u into elements 21 to 23 of p And pack u 5 p copies elements 5 to 7 of u into elements 21 to 23 of p pack u 9 p is an error because only two elements of u i e 9 and 10 are available to be copied but p has three elements Portability Operating Systems Al1l Standard Pascal Yes 7 4 38 The page procedure Description The page procedure writes a form feed control character to a file variable of type text According to Standard Pascal this procedure is supposed to affect the text file in such a way that subsequent output appears on a new page Parameter The page procedure s only parameter is a reference to the file variable of type text to which the form feed control character will be written Portability Operating Systems Al1l Standard Pascal Yes 7 4 39 The popen procedure Description The popen procedure creates a process opens a pipe i e a communications channel to the process and associa
234. he procedure is called for the first time the actual parameter is the expression Hello world which is passed into the formal parameter message So the initial value of message is Hello world The call to the built in procedure writeln causes the value of message i e Hello world to be written to the standard output stream When the procedure is called for the second time the actual parameter is the expression Good bye which is passed into the formal parameter message So the initial value of message is Good bye The call to the built in procedure writeln causes the value of message i e Good bye to be written to the standard output stream Pascal supports recursive function and procedure calls i e Pascal allows functions and procedures to call themselves either directly or indirectly For example a procedure A can call itself directly or it can call a procedure B which in turn calls procedure A Functions and procedures must be declared before they can be called This creates a problem when you have functions or procedures that call each other For example suppose you have the program below lt Ne program test output procedure a x integer begin writeln x b xt 1 end procedure b x integer begin writeln x a xt 1 end begin a 1 end If you try to compile this program the compiler will complain about the call b x 1 that occurs in procedure a because this call occurs before
235. he result of this operation is of boolean type and is true if the left operand is greater than or equal to the right operand and false otherwise When the gt operator has two operands of set type then it tests for set inclusion The result of this operation is true if all the members of the right operand are in the left operand and false otherwise Example For example 23 gt 23 results in true 23 gt 23 results in true 23 gt 23 0 results in true 23 0 gt 23 results in true 2 gt 3 results in false 2 gt 3 results in true 2 gt 3 results in true 3 gt 2 results in true 3 gt 2 results in false 3 gt 2 results in false and abc gt abc results in true abc gt abcd results in false abc gt ab results in true abc gt abd results in false abc gt aac results in true abc gt p results in false and at Dip c gt a returns true Tat bt tet S rat tb returns true Tat D Veh S Phat it Tat returns true rar gt a b toT returns false ray be gt a b toT returns false gt a return false raw gt return true 8 4 5 1 The boolean operators The boolean operators are not boolean and boolean and_then boolean or boolean or_else boolean xor boolean 8 4 5 2 not boolean Descripti
236. he setsockopt function then the getsockopt function returns the default value for the option Declaration The system include file WinSock2 ine contains the following declaration for the getsockopt function function getsockopt s SOCKET level optname integer optval address var optlen integer integer external dll ws2_32 d11 Arguments The First Argument The first argument passed to the getsockopt function is the socket from which you want to get the option value The Second Argument The second argument passed to the getsockopt function is the level at which the socket option is defined You will usually use SOL_ SOCKET as the value of this argument The Third Argument The third argument passed to the getsockopt function is an integer value that identifies the socket option whose value you want to retrieve The socket options you are most likely to retrieve are given below SO_ACCEPTCONN This option is of type BOOL and indicates whether the socket is listening e SO BROADCAST This option is of type BOOL and indicates whether you can use the socket to send broadcast messages e SO DEBUG This option is of type BOOL and indicates whether debugging is enabled SO_DONTLINGER This option is of type BOOL and indicates whether the SO_LINGER option is disabled SO _DONTROUTE This option is of type BOOL and indicates whether routine is disabled SO_ERROR This option is of integer type and is
237. hen begin temp l i l i l i 1 l i 1 temp swapped true end end until not swapped end begin randomize initialize random number generator new 1 Insert 100 random integer values into the list for i 1 to 100 do insert random 1000 1 Sort the values in the list SortList Output for i writeln J dispose end the values in the list 1 to length 1l do LEET L Syntax The syntax for defining new list types is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax list type list of component type component type type denoter domain typ type identifier new ordinal type enumerated type subrange type new pointer typ domain type domain type new structured type packed array type packed record type packed set type packed file type 1 packed list type object type string type new type new ordinal type new structured type new pointer type type denoter type identifier new typ type identifier identifier 5 7 Ordinal types Description Ordinal types define discrete groups of ordered values Each value of a given ordinal type has a unique predecessor except the first value defined by that type Each value of a given ordinal type has a unique successor except the last value defi
238. hen it the prog t reads passing each byte Finally it calls c complete the cre the built in procedure crc32 32 bit CRC for a file ram asks for the name of the file the file a character at a time to res2 rc32 4 times with zero to calculation This is part of the process of calculating CRCs J RRR KR RK KKK KK KK KK k kkk k k RK kk k k k k RK k k k RK k k k k OK program filecrc input var fn filename f file of char c char cre integer begin write Enter filename readin fn writeln Calculating CRC cre 0 reset f fn while not eof f do begin read f c Cres 2 GrG end output Ve c rC rC EG EG J3 r CY 0 Q D G O OGO writeln CRC for end tn as ty ere n hex erc Portability Operating Systems Al1 Standard Pascal No DADE 7 4 10 The dec procedure Description The dec procedure decrements the value stored in a variable Parameter 1 The first parameter is a reference to the variable of ordinal type whose value is to be decremented 2 The second parameter is an expression of integral type and is the value by which the variable is to be decremented If this parameter is not supplied then the variable is decremented by one Example dec x decrements the variable x by 1 dec x 10 decrements the variable x by 10 Portability Operat
239. his is done the declarations are placed in the same outermost scope as the declarations for the built in identifiers e g writeln As you probably know when you declare an identifier your declaration will override any other declarations of that identifier in outer scopes It is recommended that you include system include files before the reserved word program so that the many declarations they contain will be placed in the outermost scope where you can easily ignore the ones you are not interested in because if you happen to declare the same identifier in your program as one of the identifiers declared in the system include file your declaration will override the declaration in the system include file Standard Pascal requires that all declarations and definitions of the same kind must be made together in a single group and that the groups must appear in a specific order The groups are listed below in the order that they must appear in a Standard Pascal program Label declaration groups Contain label declarations Constant definition groups Contain constant definitions Type definition groups Contain type definitions Variable declaration groups Contain variable declarations Sub block declaration groups Contain function declarations and procedure declarations When the relaxed declarations extension is enabled there can be more than one of each kind of decaration definition group and groups can appear in any order excep
240. iRet listen s SOMAXCONN if iRet lt gt 0 then FatalSocketError Call to listen failed CreateListeningSocket s end CreateListeningSocket Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 9 1 Dealing with blocking Blocked Function Calls Some WinSock2 library functions can become blocked waiting for one or more required conditions to be satisfied For example the recv function which reads data from sockets requires that there be data in the sockets to be read The recv function will become blocked if it is called to read data from a socket and the socket s non blocking mode is disabled see non blocking mode below and there is no data in the socket In this case the recv function will not return to the caller until there is data in the socket or until the connection to the socket is closed at the other end NOTE If your program calls a WinSock2 library function that becomes blocked then your program will also be blocked waiting for the function to become unblocked and return from the call Sometimes you might want to allow your program to become blocked For example if the sole purpose of your program is to read some data and process it and your program can t sensibly continue until it has read the data then you might choose to allow your program to bec
241. iables to be opened in read write mode where values can be both read from and written to the files associated with the file variables If you reference the buffer variable of a file variable opened in read write mode it is unclear whether you intend to read from the file in which case the next available value from the file should be transferred to the buffer variable or whether you intend to write to the file in which case no I O should take place Because of this uncertainty it is not recommended that you use buffer variables and the low level I O procedures get and put on file variable opened in read write mode Instead it is recommended that you use the high level I O procedures read write etc to read and write from file variables opened in read write mode Buffer variables are created and destroyed when their associated file variables are created and destroyed Example The simple example program below uses a file variable f to create a file called numbers dat and uses the associated buffer variable f to write the numbers to 10 to the file program numbers var f file of integer i integer begin assign f numbers dat rewrite for i begin E a i put f end end f 1 to 10 do Syntax The syntax for referencing buffer variables is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax buffer variable file variable fi
242. ich are simply packed arrays of char having a lower bound of one and an upper bound of two or greater Fixed length strings have special properties in addition to the properties they share with other arrays Fixed length strings unlike other arrays can be compared with the relational operators Also fixed length strings unlike other arrays can be read from and written to text files as a unit using the built in procedures read readin write and writeln Variable Length Strings As an extension to Standard Pascal Irie Pascal supports variable length strings defined using the built in types string and cstring Variable length strings define sequences of characters The maximum number of characters allowed in a variable length string is fixed and is specified when the string type is defined Variable length strings defined with string are stored as length prefixed strings 1 e the actual number of characters in the string is stored in a byte or integer in front of the string A byte is used to store the actual length of the string if the maximum number of characters allowed in the string is small enough to be stored in a byte i e lt 255 An integer is used to store the actual length of the string if the maximum number of characters allowed in the string is too big to fit in a byte i e gt 255 Variable length strings defined with estring are stored as NULL terminated strings Example For example to create a variabl
243. ich is an angle in radians Example sin pi 2 returns 1 0 Portability Operating Systems Al1l Standard Pascal Yes 7 2 56 The sinh function Description The sinh function returns the hyperbolic sine of the parameter passed to it The type of the value returned by this function is always real Parameter The sinh function s only parameter is a numeric expression i e an expression of integral type or of real type which is an angle in radians Example sinh 1 returns 1 18E 00 Portability Operating Systems Al1l Standard Pascal No 7 2 57 The sizeof function Description The sizeof function returns the size in bytes of it s parameter The type of the value returned by this function is always word Parameter The sizeof function s only parameter is either a reference to a variable or a type If the parameter is a reference to a variable then this function returns the number of bytes occupied by the variable If the parameter is a type then this function returns the number of bytes occupied by variables of that type Example sizeof integer returns 4 sizeof char returns 1 sizeof real returns 8 sizeof boolean returns 4 Portability Operating Systems Al1l Standard Pascal No 7 2 58 The sqr function Description The sqr function returns the square of the value of the parameter passed to it The type of the value returned by this function is always the same as the type of the parameter
244. idual bits in the operands and the result The example above could have been written as 28 shl 3 results in 224 which is the same thing but is probably not as clear 8 4 8 7 Bit shift right shr Description As an extension to Standard Pascal Irie Pascal supports the shr operator which takes two operands left and right of integral type and performs a right bit shift operation The result of the operation is of integral type and is calculated by shifting to the right the bits in the left operand by the number of places specified by the right operand The right operand must be greater than or equal to zero NOTE Bit shifting right by N bits is the same as dividing by 2 raised to the Nth power for positive operands Example 11100 shr 3 results in 00011 Binary notation is used in the example above so that you can clearly see the individual bits in the operands and the result The example above could have been written as 28 shr 3 results in 3 which is the same thing but is probably not as clear 9 1 What are statements The statements in a program are the executable part of the program i e when executed they perform the program s actions Currently all programs created by Irie Pascal have a single thread of execution so only one statement can be executed at a time Usually the statements in a program are executed in the order in which they occur in the text of the program However some statements can change the order in
245. ieves the name of a socket s peer i e the name of the socket at the other end of the connection NOTE In the case of a connectionless socket the name retrieved will be the name of the default source or destination sockets specified by a previous call to the connect function The names of sockets specified in previous calls to the sendto function will not be retrieved by this function Declaration The system include file WinSock2 ine contains the following declaration for the getpeername function function getpeername s SOCKET name address var namelen integer integer external dll wsock32 dl1l1 Arguments The First Argument The first argument passed to the getpeername function is the socket whose peer you want to get the name of The Second Argument The second argument passed to the getpeername function is the operating system address of a buffer to store the name of the socket at the other end of the connection You should use the built in function addr to get the operating system address of this buffer The Third Argument The third argument passed to the getpeername function is the length of the buffer you supplied to store the name of the socket at the other end of the connection After the getpeername function returns successfully this argument will contain the actual length of the name stored in the buffer Return Values The getpeername function returns a value of integer type that indicates whether the
246. ifiers some of which you don t intend to use and SwW44 can be used to turn this warning back on after the file is included 2 6 Special symbols The Irie Pascal compiler recognizes the following special symbols 2 7 String literals A string literal represents zero two or more characters and can take one of two different forms 1 enclosed by single quotes 2 enclosed by double quotes String Literals Enclosed By Single Quotes String literals can be formed by enclosing the characters being represented in single quotes NOTE Single quote characters in string literals enclosed in single quotes are represented by a pair of single quote characters So Hello represents the characters Hello and Don t represents the characters Don t String literals are case sensitive so Hello is not equal to hello NOTE In Standard Pascal ISO IEC 7185 string literals must be enclosed in single quotes String Literals Enclosed By Double Quotes String literals can be formed by enclosing the character being represented in double quotes NOTE Double quote characters in string literals enclosed by double quotes are represented as a pair of double quote characters So Hello represents the characters Hello and Hello represents the characters Hello This second form of string literals is an extension to Standard Pascal and is provided mainly to make it easy to represent characters containing s
247. ilable to be read from the socket then the recv function will block and wait for data to become available to be read from the socket or for the connection to be closed connection oriented sockets only or for the connection to be reset connection oriented sockets only Non blocking mode enabled If the socket has it s non blocking mode enabled and there is no data available to be read from the socket then the recv function will return SOCKET ERROR immediately as if the call failed and if you then call the WSAGetLastError function to find out the reason for the failure the error code returned will be WSAEWOULDBLOCK You can then use the select function to find out when data becomes available to be read from the socket NOTE The constants WSAEWOULDBLOCK and SOCKET ERROR are declared in the system include file WinSock2 inc Connection Oriented Sockets When the reev function is used on connection oriented sockets it will read all of the data waiting to be read up to the size of the buffer you supply If the reev function is used on a socket that has been configured for in line reception of OOB data and there is OOB data waiting to be read then only the OOB data will be read Your program can use the ioctlsocket to determine whether there is OOB data waiting to be read If the socket at the other end of the connection has shut down the connection gracefully and all of the data sent has been received the recv function will return imm
248. ile for short Files are stored on external storage devices unlike values of other types which are stored in memory The main advantage of files over values of other types is that files can persist after the program that created them is terminated The main disadvantage of files compared to values of other types is that accessing files is usually much slower than accessing values of other types this is because accessing external storage devices is usually much slower than accessing memory In theory files can store an unlimited number of values however in practice the number of values stored in files is limited by the amount of available space on the external storage devices used to store the files The operating system controlling the external storage devices will also have a limit on the size of files but this limit is usually very large and does not affect most programs You can add to and change the values of a file using the following built in procedures seek put write writeln You can retrieve values from a file using the following built in procedures get read readin seek Before you can add values to change the existing values of or retrieve values from a file you have to associate it with a file variable NOTE This process is sometimes referred to as opening the file or opening the file variable See append open reset and rewrite When you have finished adding values to changing the existing values of or retri
249. imitive batch processor It reads lines from a text using readin and send the lines to the command processor to be executed program batch f output var f text s string err integer begin reset f open input file or standard input file while not eof f do begin readin f s writeln Executing s err system s Pass s to the command processor writeln Error code is err end end Portability Operating Systems Al1l Standard Pascal Yes Standard Pascal does not support reading from text files into variable of string type 7 4 47 The rename procedure Description The rename procedure changes the name of a file Parameters 1 The first parameter is a reference to the file variable that identifies the file to be renamed The name of the file variable is the name of the file to be renamed 2 The second parameter is an expression of string type or char type and is the new name of the file Example This program renames a single file program rename var Es text procedure syntax begin writeln Renames a file writeln Syntax ivm rename old new writeln renames a file named old to new exitcode 1 halt end begin if paramcount lt gt 2 then syntax assign f paramstr 1 Specify which file you want to rename rename f paramstr 2 Change the name of the file end Portability Oper
250. indows Socket API version that your program can support is 2 1 you could use 2 1 256 or 0102 or just 258 as the value of this argument The Second Argument The second argument passed to the WSAStartUp function is a reference to a variable of type WSADATA This argument is used by the WSAStartUp function to pass information back to your program NOTE The WSADATA type is declared in the system include file WinSock2 inc as a record type with the following important fields 1 wVersion contains the version of the Windows Sockets API that your program should use the least significant byte contains the major version number and the most significant byte contains the minor version number 2 wHighVersion contains the highest version of the Windows Sockets API that can be supported by the WinSock2 library DLL the layout of this field is the same as the layout of the first field 3 szDescription contains a description of the Windows Sockets API implementation 4 szSystemStatus contains status or configuration information that might be useful to the user or the support staff this field may be empty Return Values The WSAStartUp function returns a value of integer type that indicates whether the call was successful A value of zero means that the call succeeded A non zero value is an error code that indicates the reason why the call failed Sample Program The sample program below illustrates how to call the WSAStartUp a
251. ine However when using the Windows API you occassionally need to manipulate non virtual addresses To make this easier Irie Pascal supports a new type called address However you can t use to dereference an address because addresses are like untyped pointers i e the compiler does not know the type of the value pointed to by the address so it can not generate code to return the value pointed to be the address The address type is assignment compatible with all pointer types and vice versa so the solution to this problem is to assign the address to suitable pointer variable and then dereference the pointer variable In the case of the function below the address is known to be pointing to another address So the address to be deferenced is assigned to a pointer to an address and then this pointer is dereferenced function DereferenceAddress a address address var p address begin p a DereferenceAddress p end begin DisplayHostEntInfo pHostEnt h name is the address of a null terminated string containing the name of the host writeln NAME if pHostEnt h_name NULL then writeln NOT FOUND else if lstrlen pHostEnt h_name 1 gt sizeof strName then writeln TOO LONG else begin iRet lstrcpy addr strName pHostEnt h_name writeln strName end writeln pHostEnt h aliases is the address of a null terminated array of addresses of nu
252. information about sockets The following two web sites seemed to contain particularly useful information about sockets at the time this manual was created www users cs umn edu bentlema unix advipc ipc html www sockaddr com TheSocketsParadigm html 12 2 Introducing The WinSock2 library The WinSock2 Library Support for sockets has been included with the Windows operating system by an interface library called WinSock or more recently WinSock2 The older WinSock library will not be discussed any further in this manual The WinSock2 library supports most of the functionality provided by Berkeley Sockets usually using the same names for functions types and constants The WinSock2 library also supports many functions not present in the Berkeley Sockets library The WinSock2 library is implemented as a Windows DLL and is distributed along with a C header file which provides declarations for the WinSock2 functions types and constants You can use Irie Pascal to write programs that use the WinSock2 library The WinSock2 C header file has been translated into Pascal and is distributed with Irie Pascal for your convenience You should include the translated file i e WinSock2 inc in your programs that use the WinSock2 library A number of sample programs that use sockets are included with Irie Pascal in the InstallDir samples sockets folder NOTE InstallDir is the folder where Irie Pascal was installed The authoritative source of inform
253. ing Systems Al1 Standard Pascal No 7 4 11 The delay procedure Description The delay procedure waits for a specified number of milli seconds to elapse Parameter The delay procedure s only parameter is an expression of integral type and is the number of milli seconds that the program should wait Example delay 1000 makes the program wait for 1000 milli seconds i e 1 second Portability Operating Systems Windows Standard Pascal No 7 4 12 The delete procedure Description The delete procedure deletes components from a list or a string Parameter 1 The first parameter is a reference to the list variable or the string variable from which components are deleted 2 The second parameter is an expression of integral type and specifies the position to start deleting components from 3 The third parameter is an expression of integral type and specifies the number of components to delete If this parameter is omitted then all the components from the start position to the end of the list or string are deleted Example delete l 1 deletes all components in the list 1 delete l 2 deletes all components from lexcept the first one delete l 1 3 deletes the first three components from 1 delete s 1 deletes all characters from the string s delete s 2 deletes all characters from sexcept the first one delete s 1 3 deletes the first three characters from s
254. ing the operator to perform string concatenation i e joining When the operator has two operands of string type or char type then it performs string concatenation Any operands of char type are converted to string type before being concatenated Example Hello world results in Hello world 8 4 7 1 The set operators The set operators are Set union Set difference Set intersection in 8 4 7 2 Set union Description When the operator has operands of set type then it performs set union i e the result of the operation is a set with all the members from both operands Example laty tet Dtat tet SZT results in ta e tety SZT To see this try the example program below program setu output type letter a z var s set of letter c letter begin Ss t piat Tel ars wory taty for c a to z do if c ins then writeln c end 8 4 7 3 Set difference Description When the operator has operands of set type then it performs set difference i e the result of the operation is a set made up of the members in the left operand that are not in the right operand Example atp Di3 PONS ree pa Lra e results in tbr Dry ret rat To see this try the example program below program setd output type letter a z var s set of letter c letter begin s lr ast Hh Nay rat aty Jy for c a
255. ingle quotes i e you can enclose string literals containing single quotes with double quotes without using double single quotes like instead of Examples vt Don t Say Hello l SS E n Don t Say Hello IRa S a Syntax string literal empty string non empty string empty string N E N E i rum non empty string string element one string element one string element one string element two string element two string element two printable character any character including a space that has a visual representation string element on l orintable character string element two printable character NOTE The production for printable character doesn t use the usual notation because 1 it s tedious to write out every possible printable character and 2 the definition for a printable character depends on the character set being used 2 8 1 1 What are integers Integers are numbers with no fractional part and can take one of the following three forms Integers Decimal notation Integers Hexadecimal notation Integers Binary notation Irie Pascal supports integers with values between 2147483647 and 4294967295 Syntax NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax integer number decimal integer hexadecimal integer
256. ion PURPOSE Displays the information that was obtained from a DNS or Reverse DNS lookup PARAMETER s 1 pHostEnt a pointer to the sockets API hostent structure that contains the result of the lookup NOTES This procedure uses the Windows API functions lstrlen and lstrcpy to manipulate strings in C format i e null terminated arrays of char These functions are used because the strings in the hostent structure are in C format Since these functions are not described in the online help because they are Windows API functions not Irie Pascal functions a brief description is given below for persons not already familiar with these functions lstrlen returns the length of the string not counting the null terminator lstrepy copies the string pointed to by it s second argument into the memory pointed to by it s first argument the null terminator is also copied procedure DisplayHostEntInfo pHostEnt p_hostent const MAX ASCII_ADDRESS 15 var AddrTemp AddrAddr AddrRet address iRet integer strAddress cstring MAX ASCII ADDRESS strName cstring PURPOSE Returns the address pointed to be another address PARAMETER s 1 a an address pointing to another address RETURNS The address pointed to by the parameter a NOTES Irie Pascal pointer variables contain virtual addresses that are only meaningful to the Irie Pascal Run Time Eng
257. ion If the filename matches the file specification then the value true is returned and if the filename does not match the file specification then the value false is returned Parameter 1 The first parameter file spec is an expression of type string or type char which contains the file specification with which the filename is being matched The file specification may contain the following wildcard characters and The character if used in the file specification matches any zero or more characters in the filename The character if used in the file specification matches any single character in the filename 2 The second parameter filename is an expression of type string or type char which contains the filename to be matched with the file specification The filename is not tested for validity nor does the file have to exist Example fFilematch file txt file txt returns true fFilematch file txt otherfile txt returns false Filematch txt file txt returns true fFilematch txt otherfile txt returns true Filematch a c abc returns true filematch a c agc returns true Filematch a c Tazo returns true Filematch a abc returns false fFilematch a c ab returns false fFilematch c bc returns false Filematch c abc returns true Filematch a avd returns true Portability Operating Systems
258. ion dbmsname Description The dbmsname property of the connection object type contains the name of the database engine connected to NOTE If the connection is to a MySQL database then this property always constains MySQL dbmsname is a read only property of type string Example For example if conn is a connection object reference with an open connection to a database engine then the following conn dbmsname is equal to the named of the database engine referenced by conn Portability Operating Systems Al1l Standard Pascal No 5 15 20 8 connection dbmsver Description The dbmsver property of the connection object type contains the version of the database engine connected to dbmsver is a read only property of type string Example For example if conn is a connection object reference with an open connection to a database engine then the following conn dbmsver is equal to the version of the database engine referenced by conn Portability Operating Systems Al1l Standard Pascal No 5 15 20 9 connection dmver Description The dmver property of the connection object type contains the version of the ODBC driver manager connected to NOTE If the connection is to a MySQL database then this property always constains an empty string dbmver is a read only property of type string Example For example if conn is a connection object reference with an open connection to an ODBC database engine then the f
259. ion request was accepted then you should use null for this argument The Third Argument The third argument passed to the accept function is a variable of integer type and is passed by reference When you call the accept function the value stored in this argument is either the size of the variable that was passed in the second argument or null if no variable was passed in the second argument If this argument is not null then when the accept function returns this argument contains the actual length of the name stored in the second argument Return Values The accept function returns a new socket that is connected to the socket whose connection request was accepted if the call is successful If the call fails then the value IVVALID_SOCKET is returned and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail NOTE INVALID _ SOCKET is declared in the system include file WinSock2 inc After a connection request is accepted the listening socket continues to be available to accept more connections and the new connected socket should be used to send data to and receive data from the socket that requested the connection Example The following code fragment shows one way to accept connections ConnectedSocket accept ListeningSocket null null if ConnectedSocket lt gt SOCKET ERROR then begin use the connection to send and receive data end else b
260. ion to find out the reason for the failure the error code returned will be WSAEWOULDBLOCK You can then use the select function to monitor the progress of the connection request As long as a socket has a connection request pending calling the connect function on that socket will fail NOTE The constants WSAEWOULDBLOCK and SOCKET_ERROR are declared in the system include file WinSockz2 inc If the listening socket accepts the connection request then a communications link is established between the socket that requested the connection and the socket created by the accept function and both of these sockets are ready to send and receive data Any attempt to reconnect a socket that is already connected will fail and the WSAGetLastError function will return WSAEISCONN NOTE The constant WSAEISCONN is declared in the system include file WinSock2 inc Connectionless Sockets When the connect function is used on a connectionless socket it does not send a connection request instead the connect function will specify the name of destination socket or sockets for the send function and the name of source socket or sockets for the recv function The send function will send datagrams to the destination socket or sockets and the recv function will silently discard any datagrams received from sockets other than the source socket or sockets Unbound Sockets If the connect function is used on a unbound socket see the bind function for more information
261. ions 7 3 1 Function declarations 7 4 Built in Procedures 7 4 1 The built in procedures 4 2 Th nd pr r 7 4 3 The assert procedure 7 4 4 The assign procedure 7 4 5 The chdir procedure 7 4 6 The close procedure 7 4 7 The closedir procedure 7 4 8 The clrscr procedure 7 4 9 The crc32 procedure 7 4 10 The dec procedure 7 4 11 The delay procedure 4 12 The delete pr r 7 4 13 The dispose procedure 7 4 14 The erase procedure 7 4 15 The exec procedure 7 4 16 The exit procedure 1 4 17 The fill procedure 7 4 18 The flush procedure 7 4 19 The fsplit procedure 7 4 20 The get procedure 7 4 21 The getdate procedure 4 22 The getfiledate pr r 7 4 23 The getfilemode procedure 7 4 24 The getfiletime procedure 7 4 25 The gettime procedure 7 4 26 The gotoxy procedure 7 4 27 The halt procedure 7 4 28 The inc procedure 7 4 29 The insert procedure 7 4 30 The intr procedure 7 4 31 The mkdir procedure 4 32 The m r 7 4 33 The msdos procedure 7 4 34 The new procedure 7 4 35 The open procedure 7 4 36 The opendir procedure 7 4 37 The pack procedure 7 4 38 The page procedure 7 4 39 The popen procedure 7 4 40 The put procedure 7 4 41 The randomize procedure 4 42 The rawr r r 7 4 43 The rawwrite procedure 7 4 44 The read procedure 7 4 45 The readdir procedure 7 4 46 The readin procedure 1 4 47 The rename procedure 7 4 48 The reset procedure 7 4 49
262. ions Variable declarations Function declarations Procedure declarations 2 9 4 1 What are directives Directives are special identifiers that can be used to give the compiler extra information about a declaration definition The compiler recognizes directives only at specific points in a declaration definition and this recognition is not affected by and does not affect any meaning the directive s identifiers may have outside of these specific points So for example the forward directive is recognized even if the identifier forward has been declared to have some other meaning and the use of the forward directive does not affect any meaning that forward has been declared to have The supported directives are listed below e The external directive The forward directive 2 9 4 2 The external directive The external directive specifies that the function or procedure being declared is located outside of the program and the function or procedure body is omitted from the declaraion Currently the only external functions and procedures supported are functions and procedures located in Windows DLLs Example The following external function declaration is taken from the winuser inc include file and declares the Windows MessageBox function function MessageBox hWnd _HWND lpText lpCaption LPSTR uType UINT integer external dll user32 dll name MessageBoxA stdcall Syntax The syntax for declaring external fun
263. is activated it is an error if eof f is true Error Handling This error is never reported 18 44 Using undefined variables Official Description 6 7 1 An expression denotes a value unless a variable denoted by a variable access contained by the expression is undefined at the time of its use in which case that use is an error Simplified Description In other words it is an error to use a variable with an undefined value in an expression Error Handling This error is reported only if checking for undefined values is enabled and the variable s type is one of the supported types see Run Time Project Options in the Irie Pascal User s Manual 18 45 Real division by zero Official Description 6 7 2 2 A term of the form x y is an error if y is zero Simplified Description In other words for real division it is an error if the denominator is zero Error Handling This error is always reported 18 46 Integer division by zero Official Description 6 7 2 2 A term of the form i div j is an error if j is zero Simplified Description In other words for integer division it is an error if the denominator is zero Error Handling This error is always reported 18 47 Modulus of zero or negative Official Description 6 7 2 2 A term of the form i mod j is an error if j is zero or negative Simplified Description In other words for the modulus operation it is an error if the right operand is zer
264. is enabled 18 9 Using out of range set value parameters Official Description 6 6 3 2 For a value parameter it is an error if the actual parameter is an expression of a set type whose value is not assignment compatible with the type possessed by the formal parameter Simplified Description In other words when you pass set values into formal parameters during a function or procedure call the values must be assignment compatible with the type of the formal parameters into which they are passed If you think about it this makes sense since passing a value into a formal parameter is very much like assigning the value to the formal parameter Error Handling This error is reported if range checking is enabled 18 10 Output to file not open for writing Official Description 6 6 5 2 It is an error if the file mode is not generation immediately prior to any use of put write writeln or page Simplified Description In other words it is an error to perform output on a file which is not open for writing i e the file is either not open or open for reading Error Handling This error is reported if I O checking is enabled 18 11 Output to undefined file Official Description 6 6 5 2 It is an error if the file is undefined immediately prior to any use of put write writeln or page Simplified Description In other words it is an error to perform output on a file which does not exist Error Handling This err
265. is transfered to the statements in the statement sequence in the order in which they occur in the program text unless diverted by one of the statements executed 3 Execution of the compound statement is terminated when either the execution of the last statement in the statement sequence is terminated or when one of the statements in the statement sequence transfers program execution to a statement outside of the compound statement Ne You usually use compound statements when the rules of Pascal say that only one statement is allowed at a particular point in the program but you want to put more than one statement there The solution to this problem is to put the statements into a compound statement Example For example look at the program fragment below write Do you want to continue readin answer if answer n or answer N then begin writeln Program terminated by user halt end here we want to write a message to the screen and stop if the user answers n or N but this requires two statements and the then part of an if statement allows only a single statement The solution as you can see is to put the two statements into a compound statement Syntax NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax compound statement begin statement sequence end statement sequence statement statement 9 7 If statement Description If sta
266. ise 7 end at the point that otherwise is used the following case constants have already been specified Tatoo t Z p TA bra Zt p and 0 5 OT so otherwise specifies the remaining case constants which in this case are all the other values of the char type 13 5 Allow relaxed parameter list congruity As an extension to Standard Pascal Irie Pascal relaxes the rules when deciding whether two formal parameter lists are congruent NOTE This extension is the only one that can not be disabled A rarely used feature of the Pascal language is the ability to pass functions and procedures to other functions and procedures Functions are passed using functional parameters and procedures are passed using procedural parameters Functional and procedural parameters come in two forms actual and formal just like the other kinds of parameters value and variable parameters Actual functional parameters specify the functions being passed and formal functional parameters are used to reference the functions being passed inside the receiving functions or procedures In a similar way actual procedural parameters specify the procedures being passed and formal procedural paramters are used to reference the procedures being passed inside the receiving functions or procedures The formal parameter list of the function specified by an actual functional parameter must be congruent with the formal parameter list of the corresponding formal functional parameter Th
267. ith the built in procedures open and popen to specify the mode a file or pipe should be opened in The file mode constants are listed below appendmode readmode writemode 4 2 61 1 The permission constants Irie Pascal supports ten built in integer constants which can be used with the built in procedures mkdir and getfilemode to specify or identify read write and execute search permissions as well as to find out whether a file is a directory folder The permission constants are listed below dir_bit grp_r grp_w grp_x th th z Ps c Za c A lan EE EE EE D EE EE EE EE E Za lan ba Example For example the simple program below asks for a filename and then displays the all the file permissions for the file program AllPermissions input output var s filename mode integer isdir boolean begin write Enter filename readin s s fexpand s getfilemode s mode isdir mode and dir bit lt gt 0 if isdir then writeln s is a directory teln s is not a directory te Owner permissions mode and usr_r lt gt 0 then ite Read mode and usr_w lt gt 0 then ite Write mode and usr_x lt gt 0 then isdir then te Search BRR FR o H H n H o h hA A zZ eH g ezz 0 e Execute te Group permissions mode and grp_r lt g
268. itial value out of range Official Description 6 8 3 9 For a for statement it is an error if the value of the initial value is not assignment compatible with the type possessed by the control variable if the statement of the for statement is executed Simplified Description In other words it is an error if the following two conditions are met The initial value specified in a for statement is not in the range specified by the type of the control variable At least one iteration of the for loop is executed For example given type num 1 100 var n num then the following are errors 0 to 100 do writeln n 101 downto 1 do writeln n for n for n But the following are not errors since the for loops are never started and therefore no assignments are made to n for n 101 to 1 do writeln n for n 0 downto 100 do writeln n Error Handling This error is reported if range checking is enabled 18 54 For loops final value out of range Official Description 6 8 3 9 For a for statement it is an error if the value of the final value is not assignment compatible with the type possessed by the control variable if the statement of the for statement is executed Simplified Description In other words it is an error if the following two conditions are met The final value specified in a for statement is not in the range specified by the type of the control variable At least one iterati
269. ive source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 8 1 The listen function Description The listen function converts a data socket into a listening socket In this manual the term data socket means a socket that you can use to send and receive data and the term listening socket means a socket that you can use to listen for attempts by other sockets to connect When you first create a socket it is a data socket by default Declaration The system include file WinSock2 ine contains the following declaration for the listen function function listen s SOCKET backlog integer integer external dll ws2_32 d11 Arguments The First Argument The first argument passed to the listen function is the data socket socket that you want to convert into a listening socket The Second Argument The second argument passed to the listen function is the maximum length of the queue of pending connections If you pass a value for this argument that is too large then the underlying service provider will choose an appropriate value If you are not sure what value you should use for this argument then use SOMAXCONN which will cause the underlying service provider to choose an appropriate value NOTE The constant SOMAXCONN is declared in the system include file WinSock2 inc Return Values The listen function returns a va
270. l No 5 15 15 shortint type Description shortint is the type identifier for a built in ordinal type whose values are signed 16 bit integers between 32767 and 32767 This type is provided to make it easier to call calling external functions procedures that expect and or produce signed 16 bit integers NOTE Some functions procedures in the Windows API expect and or produce signed and unsigned 16 bit integers Portability Operating Systems Al1 Standard Pascal No 5 15 16 shortword type Description shortword is the type identifier for a built in ordinal type whose values are unsigned 16 bit integers between 0 and 65535 This type is provided to make it easier to call calling external functions procedures that expect and or produce signed 16 bit integers NOTE Some functions procedures in the Windows API expect and or produce signed and unsigned 16 bit integers Portability Operating Systems Al1l Standard Pascal No 5 15 17 single type Description single is the type identifier for a built in type whose values are 32 bit real numbers This type is provided to make it easier to call calling external functions procedures that expect and or produce 32 bit real numbers NOTE Some functions procedures in the Windows API expect and or produce 32 bit real numbers Portability Operating Systems Al1l Standard Pascal No 5 15 18 text type Description text is the type identifier for a built in file type whose val
271. l declaration group constant definition group type definition group variable declaration group function declaration procedure declaration declarative part declaration group directive forward directive external directive formal parameter list formal parameter section formal parameter section formal parameter section value parameter specification variable parameter specification procedure parameter specification function parameter specification function heading function identifier formal parameter list result type Function identification function function identifier fFunction identifier identifier function parameter specification function heading identifier letter letter digit identifier list identifier identifier procedure block block procedure heading procedure identifier formal parameter list procedure identification procedure procedure identifier procedure identifier identifier procedure parameter specification procedure heading statement part compound statement statement sequence statement statement type identifier identifier value parameter specification identifier list type identifier variable parameter specification var identifier list type identifier 7 6 1 Calling external functions and pro
272. l depend on the variable s type It is a common shorthand to refer to the value stored in a variable as the value of the variable or the variable s value Variables are dynamic and can be both created and destroyed When a variable is created it s initial value i e it s value before a value has been explicitly stored in it is said to be undefined It is an error to retrieve an undefined value from a variable Values are stored inside variables by referencing the variables in the left hand side of assignment statements and the values stored inside variables are retrieved by referencing the variables in expressions NOTE The method used to reference a variable depends on what kind of variable it is Variables can be grouped into the following two categories 1 named variables 2 anonymous variables 6 2 Named variables Description Named variables are introduced in variable declarations which define the type of each variable and associate an identifier i e a name with each variable Named variables are created when the block containing their variable declaration is activated and destroyed when the activation of the block is terminated In the case of variables introduced in the variable declarations of the main program block this means that these variables will be created when the program is activated and destroyed when the program is terminated In the case of variables introduced in the variable declarations of function
273. le of type text If the optional parameter is supplied then the eoln function tests the file associated with the parameter If the optional parameter is not supplied then the file associated with the built in variable input is tested Portability Operating Systems Al1l Standard Pascal Yes 7 2 16 The exp function Description The exp function returns the value of the mathematical constant e raised to a power The type of the value returned by this function is always real Parameter The exp function s only parameter is a numeric expression i e an expression of integral type or of real type which specifies the power to which e should be raised to Example exp 2 returns PESO Oe xe Portability Operating Systems Al1l Standard Pascal Yes 7 2 17 The fexpand function Description The fexpand function expands a filename into a full pathname and returns the full pathname The type of the value returned by this function is always string Parameter The fexpand function s only parameter is an expression of string type or char type which contains the filename to to be expanded NOTE If the filename is already expanded then it is returned unchanged Portability Operating Systems Al1l Standard Pascal No 7 2 18 The filematch function Description The filematch function accepts two parameters as described below and returns a value of type boolean which indicates whether the filename matches the file specificat
274. le variable Where file variable is a reference to a file variable 6 7 List variables Description List variables are used to store values of list types i e collections of values of the same type The type of each value in a list is called the list s component type An list s component type may be any type including a list type so it is possible to define lists of lists The built in procedure new must be used to initialize list variables before they can be used to store values and the built in procedure dispose should be used to clean up after list variables that are no longer required The number of values in each list is theorectically unlimited in practice the amount of memory available will limit the size of lists Each value in a list is identified by index value of integral type Each value in a list is stored in a seperate component of the list called a list element or a selected variable Each element of a list can be referenced individually in order to store values into and retrieve values from specific elements See the syntax section below for details Selected Variables Selected variables are created by calling the built in procedure insert to insert values into lists and selected variables are destroyed by calling the built in procedure delete to remove values from lists NOTE The built in procedure dispose will remove all values from lists Selected variables are referenced by indexing the list variabl
275. lement two printable character NOTE The production for printable character doesn t use the usual notation because 1 it s tedious to write out every possible printable character and 2 the definition for a printable character depends on the character set being used 2 3 Reserved words Reserved words also called keywords are symbols that have pre defined and fixed meanings to the Irie Pascal compiler The case of reserved words is usually not significant so although the reserved words listed below are all in lowercase by default the compiler will recognize reserved words regardless of the case of the letters NOTE There is a compiler option p that will make reserved words and identifiers case sensitive The reserved words recognized by the compiler are listed below along with links to information describing how the reserved words are used NOTE Reserved words added because of extensions to Standard Pascal are listed in red and and boolean operator and bitwise operator and_then and_then operator array array types begin compound statement case record types case statement class object types const constant definitions div div operator do while statement for statement with statement downto for statement else record types case statement if statement end record types compound statement case statement file file types for for statement function functions and procedures goto goto statement if if state
276. lete program and makes the following assumptions 1 conn is an connection object reference for an open connection object 2 conn is connected to a database with a table named customer 3 The customer table has the fields last_name and first_name new rs rs open conn select last name first name from customer rsforward while not rs eof begin writeln rs field last name rs field first name rs movenext end rs close dispose rs Parameters 1 This first parameter to this method is a reference to an open connection object 2 The second parameter to this method is an expression of type string that evaluates to a SQL statement that will return one or more recorsets 3 The third parameter to this method is an expression of type integer that evaluates to the same value as one of the built in recordset type constants you should just use one of the recordset type constants directly If recordset type is not specified then the default recordset type is assumed Portability Operating Systems Al1l Standard Pascal No 5 15 21 6 recordset eof Description The eof property of the recordset object type indicates whether or not the recordset is currently at end of file NOTE eof is a read only property of type boolean Example For example if you have a recordset object reference rs with an open recordset then rs eof indicates whether the current recordset referenced by rs is at end of file
277. ll terminated strings containing alternative names for the host writeln ALIASES AddrAddr pHostEnt h aliases if AddrAddr NULL then writeln None else begin AddrTemp DereferenceAddress AddrAddr while AddrTemp lt gt NULL do begin if lstrlen AddrTemp gt 0 then begin if lstrlen addrTemp 1 gt sizeof strName then writeln TOO LONG else begin iRet lstrcpy addr strName AddrTemp writeln strName end end else writeln EMPTY AddrAddr AddrAddr sizeof address AddrTemp DereferenceAddress AddrAddr end end writeln if pHostEnt h_addrtype lt gt AF_ INET then writeln Invalid address type else if pHostEnt h length lt gt sizeof address then writeln Invalid address length else begin pHostEnt h addr list is the address of a null terminated array of addresses of IP addresses of the host writeln ADDRESSES AddrAddr pHostEnt h addr list if AddrAddr NULL then writeln None else begin Get the first element of the array AddrTemp DereferenceAddress AddrAddr while AddrTemp lt gt NULL do begin Dereference the current array element to get the IP address AddrTemp DereferenceAddress AddrTemp Convert the IP address from binary format to a human readable format like nnnn nnnn nnnn nnn AddrRet inet_ntoa AddrTemp if AddrRet null or 1lstrlen AddrRet 1 gt sizeof strAddress
278. llowing three lines rewrite f writeln f sl writeln f s2 is that a text file out txt is opened and two lines are written to it The first line will be first and the second will be second Syntax NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax program program heading program block identifier letter letter digit identifier list identifier identifier program block block program heading program identifier program parameter list program parameter list identifier list 12 1 What are sockets NOTE The information provided in this manual about sockets is just an introduction and is intended to give you a basic understanding of how to write Irie Pascal programs that use sockets If you intend to write serious programs i e programs that you use for important purposes and which must be robust and reliable that use sockets then you should consult more advanced and complete sources of information about sockets Introduction To Sockets Sockets were first introduced by the University of California Berkeley in their version of UNIX as a method for processes i e running programs to communicate with each other Sockets are now widely supported by many operating systems and the concept has been expanded to include processes communicating over a network Sockets provide a useful abstraction that insulates commu
279. ln at end of file 18 44 Using undefined variables 18 45 Real division by zero 18 46 Integer division by zero 18 47 Modulus of zero or negative 18 48 Integer overfl nderfl 18 49 Returning undefined value from function 18 50 Assigning out of range ordinal values 18 51 Assigning out of range set values 18 52 Non matching case index 18 53 For loops initial value out of range 18 54 For loops final value out of range 18 55 Reading invalid integer values 18 56 Reading out of range integer values 18 57 Reading invalid numeric values 1 Reading when file is not open 18 59 Writing with TotalWidth or FracDigits less than one 18 60 Problems with program parameters 18 61 Problems with conformant arrays 19 Appendix G I O error codes 19 1 T O error codes 20 Appendix H Irie Pascal Grammar 20 1 Grammar notation 20 2 Irie Pascal grammar 1 1 Preface This is the Irie Pascal Programmer s Reference Manual and describes the Irie Pascal language This manual is not a tutorial and does not attempt to teach programming if you are new to programming or new to Pascal you may need additional information Fortunately there are many excellent books which teach programming in Pascal If you decide to purchase a Pascal book you should look for one that covers Standard Pascal See Pascal book recommendations from the Irie Tools website See the Irie Pascal User s Manual for mor
280. lue of i shall be assignment compatible with the index type of the array variable a For example given var a array 1 100 of real z packed array 1 100 of real i integer and pack a i z or unpack z a i then i shall be assignment compatible with 1 100 the index type of a 11 1 What are program parameters Description Program parameters are identifiers which appear at the top of the program in the program heading after the program name and between parentheses In addition to appearing after the program name most program parameters must also appear in a variable declaration in the main program block Two special program parameters input and output are the exceptions to this rule The appearance of the two special program parameters in the program heading automatically declares them as file variables associated with the standard input and standard output streams You can use program parameters to access the command line arguments passed to your program NOTE You can also use paramcount and paramstr to access command line arguments Example For example suppose you want to write a program to append two files together writing the appended files to a third file then you might write a program similar to the program below RRR RRK RAKE RK KR KKK EK KKK KKK KKK KEK KK KR KKK KKK KR EKER KKK KER KK KEKE RK KAR KKKKK KR This program appends two files together writing the appended files x out to a third
281. lue of integer type that indicates whether the call was successful A value of zero means that the call succeeded A value of SOCKET _ ERROR indicates that the called failed and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail NOTE The constant SOCKET ERROR is declared in the system include file WinSock2 inc Example The following example function is taken from the sample sockets programs distributed with Irie Pascal and demonstrates how to create a socket bind it and convert it into a listening socket This function creates a listening socket First it creates a socket Then it binds the socket to a particular port i e the port we want to listen on The socket is not bound to any particular address INADDR_ANY is used instead because connections will be accepted from any IP address Finally listen is called to convert the socket to a listing socket function CreateListeningSocket port integer socket var s socket sa sockaddr_in iRet integer begin CreateListeningSocket s createsocket AF INET SOCK_STREAM 0 if s INVALID SOCKET then FatalSocketError CreateSocket call failed fill sa 0 sa sin_family AF_INET sa sin_port htonl port shr 16 sa sin_addr htonl INADDR_ANY shr 16 iRet bind s addr sa sizeof sa if iRet lt gt 0 then FatalSocketError Call to bind failed
282. lues Non matching case index For loops initial value out of range For loops final value out of range Reading invalid integer values Reading out of range integer values Reading invalid numeric values Reading when file is not open Writing with TotalWidth or FracDigits less than one Problems with program parameters Problems with conformant arrays 18 2 Array index out of bounds Official Description 6 5 3 2 For an indexed variable closest containing a single index expression it is an error if the value of the index expression is not assignment compatible with the index type of the array type Simplified Description In other words it is error to access an array component that does not exist For example given var a array 1 20 of char then a 0 is an error since the index expression i e 0 is not assignment compatible with the index type i e 1 10 of the array type NOTE There is no Oth component of the array a Error Handling This error is reported if range checking is enabled 18 3 Accessing inactive variant Official Description 6 5 3 3 It is an error unless a variant is active for the entirety of each reference and access to each component of the variant Error Handling This error is reported if the following two conditions are met 1 Range checking is enabled 2 The number of values defined by the variant selector s type is less than or equal to 1024 18 4 Derefer
283. lution to this problem is to shift the value in the upper 16 bits into the lower 16 bits before the assignment into the shortint variable You can do this by changing the x swap x into either x swap x shr 16 or x swap x div 10000 Portability Operating Systems All Standard Pascal No 7 2 64 The system function Description The system function passes a command to the command processor for execution and returns the resulting error code If there is an error executing the command then a non zero value indicating the kind of error is returned If there is no error executing the command then the value returned is zero The type of the value returned by this function is always integer Parameter The system function s only parameter is an expression of string type or char type and is the command to send to the command processor Example For example the simple program batch pas below is a very primitive batch processor It sends each line in the input file to the command processor to be executed program batch f output var f text s string err integer begin reset f open input file or standard input file while not eof f do begin readin f s writeln Executing s err system s Pass s to the command processor writeln Error code is err end end Portability Operating Systems Al1 Standard Pascal No 7 2 65 The tan function
284. m error writeln Unknown Platform end end Portability Operating Systems Al1l Standard Pascal No 4 2 37 platform_fbsd Description platform_fbsd can be compared with the value returned by the built in function platform to determine whether the current platform is FreeBSD i e the interpreter running your program is from the FreeBSD edition of Irie Pascal Example The following simple program displays the current platform program ShowPlatform output begin case platform of latform dos writeln DOS form os2 writeln OS 2 form win32 writeln Windows form linux writeln Linux rm fbsd writeln FreeBSD rm solaris writeln Solaris x86 orm solaris sparc writeln Solaris Sparc O O O T oeat aTa Fh Ph th 9 9 9 w H T cla ean ce platform error writeln Unknown Platform end end Portability Operating Systems Al1l Standard Pascal No 4 2 38 platform_linux Description platform_linux can be compared with the value returned by the built in function platform to determine whether the current platform is Linux i e the interpreter running your program is from the Linux edition of Irie Pascal Example The following simple program displays the current platform program ShowPlatform output begin case platform of platform dos writeln DOS platform_os2 writeln 0S 2
285. m supports the built in procedure clrscr Example if supported feature_clrscr then clrscr Portability Operating Systems All Standard Pascal No 4 2 8 feature delay delay supported Description feature_delay can be used to determine if the current platform supports the built in procedure delay Example if supported feature delay then delay 100 Portability Operating Systems Al1l Standard Pascal No 4 2 9 feature_gotoxy gotoxy supported Description feature_gotoxy can be used to determine if the current platform supports the built in procedure gotoxy Example if not supported feature_gotoxy then begin writeln gotoxy not supported on the current platform abort end Portability Operating Systems Al1l Standard Pascal No 4 2 10 feature_idispatch COM ActiveX objects supported Description feature_idispatch can be used to determine if the current platform supports accessing COM objects using the IDISPATCH interface Example program SendEmailWithCDONTS output begin obj object begin if supported feature_idispatch then begin obj createobject CDONTS NewMail obj send from address to address subject body 1 dispose obj end else writeln Can not send email end Portability Operating Systems Al1l Standard Pascal No 4 2 11 feature_intr intr supported Description feature_intr can be used to determine if the current platform
286. me line have the same precedence Operations with operators of the same precedence are performed left to right Parantheses can be used to control the order in which operations are performed by grouping operations that should be performed first not div mod and and then or or else xor So for example with the expression below 2 3 1 the addition would be performed before the subtraction This is because and have the same precedence and so the operations are performed from left to right However since has a higher precedence then with the expression below 2 e3 1 the multiplication is permormed before the addition Using the same example above you can force the addition to be performed first by using parentheses like so 2 3 1 For more complicated expressions you can use nested parentheses in which case the operatings enclosed in the inner most parentheses are performed first So for example given 2 4 1 4 div 2 2 the first operation performed is 2 2 which yields 4 resulting in the expression below 2 4 1 4 div 4 Now we have two nested parentheses at the same level so which operation is performed first Well operations at the same level of precedence are performed left to right so the 4 1 is performed next resulting in 2 3 4 div 4 Next the 4 div 4 is performed resulting in 2 4 B 1 Next the 3 1 is performed resulting in 2S which results in the
287. ment in in operator label labels list list types mod mod operator nil nil constant pointer types not not boolean operator not bitwise operator object object types of array types file types list types set types record types case statement or or boolean operator or bitwise operator or_else or else operator otherwise record types case statement packed array types file types list types set types record types procedure functions and procedures program Irie Pascal grammar record record types repeat repeat statement set set types shl shl operator shr shr operator then if statement to for statement type type definitions until repeat statement var variable declarations function declarations procedure declarations while while statement with with statement xor xor boolean operator xor bitwise operator NOTE Although reserved words look like identifiers you can not use reserved words as identifiers 2 4 Separators The separators are spaces tabs end of lines and comments and they can appear anywhere in an Irie Pascal program without altering it s meaning except that At least one separator must appear between consecutive identifiers reserved words integers or real numbers e Separators can not occur inside any other language element symbol Comments are sequences of characters enclosed in or and or As an extension to Standard Pascal Iri
288. ment compound statement conditional statement repetitive statement with statement subrange type constant constant tag field identifier tag type ordinal type identifier ry Ww term factor multiplying operator facto type definition identifier type denoter type definition group type type definition type definition type denoter type identifier new typ type identifier identifier unsigned constant integer number real number character literal string literal constant identifier nil value parameter specification identifier list type identifier variable access entire variable component variabl identified variable selected variable buffer variable variable declaration identifier list type denoter variable declaration group var variable declaration variable declaration variabl identifier identifier variable parameter specification var identifier list type identifier variant case constant list field list variant body variant list variant part completer variant part completer variant list variant variant variant part case variant selector of variant body variant part completer otherwise else field list variant selector tag field tag type while statement whil
289. mission of data or both and can have the follow values SD RECEIVE subsequent calls to the recv function on the socket will be disallowed This has no effect on the lower protocol layers For TCP sockets if there is still data queued on the socket waiting to be received or data arrives subsequently the connection is reset since the data cannot be delivered to the user For UDP sockets incoming datagrams are accepted and queued In no case will an ICMP error packet be generated e SD_SEND subsequent calls to the send function are disallowed For TCP sockets a FIN will be sent after all data is sent and acknowledged by the receiver e SD BOTH disables both sending and receiving as described above Return Values The shutdown function returns a value of integer type that indicates whether the call was successful A value of zero means that the call succeeded A value of SOCKET ERROR indicates that the called failed and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail NOTE The constants SO_LINGER SD_RECEIVE SD_SEND SD_BOTH and SOCKET ERROR are declared in the system include file WinSock2 inc Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 15 2 The closesocket function Description The
290. mplementation defined Irie Pascal allows string literals and character literals to be formed from any printable character 16 3 Provision of tokens and delimiting characters 6 1 9 Provision of the reference tokens and of the alternative token and of the delimiting characters and is implementation defined Irie Pascal provides the reference tokens the alternative token and the delimiting characters 16 4 Size and precision of real values 6 4 2 2 b The values of the real type shall be an implementation defined subset of the real numbers denoted by signed real The real numbers described by the ISO IEC 7185 have infinite range and infinite precision Implementations are allowed to limit the maximum range and precision of real numbers Irie Pascal uses 64 bit reals stored as specified by the following standard IEEE standard for binary floating point arithmetic ANSI IEC std 754 1985 16 5 Character set 6 4 2 2 d The values of char type shall be the enumeration of a set of implementation defined characters some possibly without graphic representation Values of char type in Irie Pascal are the enumeration of all characters printable and non printable 16 6 Ordinal values of characters 6 4 2 2 d The ordinal numbers of each value of char type are implementation defined Irie Pascal uses the position of each value of char type in the current character set as it s ordinal number So for example since the sp
291. n The supported function The swap function The system function The tanh function The trim function The unixplatform function The upcase function The uppercase function The urldecode function The version function The wait function The wherex function The wherey function 13 16 Enable non standard procedures When the enable non standard procedures extension is enabled Irie Pascal supports the use of the non standard procedures and the use of standard procedures in non standard ways The non standard procedures are listed below The append procedure The assert procedure The assign procedure The chdir procedure The close procedure The closedir procedure The clrscr procedure The cre32 procedure The dec procedure The delay procedure The delete procedure The erase procedure The exec procedure The exit procedure The fill procedure The flush procedure The fsplit procedure The getdate procedure The getfiledate procedure The getfilemode procedure The getfiletime procedure The gettime procedure The gotoxy procedure The halt procedure The inc procedure The insert procedure The intr procedure The mkdir procedure The move procedure The msdos procedure The open procedure The opendir procedure The popen procedure The randomize procedure The rawread procedure The rawwrite procedure The readdir procedure The rename procedure The rewinddir procedure The rmdir
292. n converts a value of type u_short from TCP IP network byte order which is big endian to host order Declaration The system include file WinSock2 ine contains the following declarations for the u_ short type and the ntohs function u_short shortint function ntohs netshort u_short u_short external dll ws2_32 d11 Arguments The only argument passed to the ntohs function is the u _short value that you want to convert to host byte order Return Values The ntohs function returns the u_ short value in host byte order Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 16 11 The setsockopt function Description The setsockopt function sets the current value of a socket s option Declaration The system include file WinSock2 ine contains the following declaration for the setsockopt function function setsockopt s SOCKET level optname integer optval address optlen integer integer external dll ws2_32 d11 Arguments The First Argument The first argument passed to the setsockopt function is the socket for which you want to set the option value The Second Argument The second argument passed to the setsockopt function is the level at which the socket option is defined You will usually use SOL_ SOCKET as the value of this argument
293. nction createsocket af typ protocol integer SOCKET external dll ws2_32 d11 name socket Arguments The First Argument The first argument passed to the CreateSocket function is an expression of integer type This argument indicates the address family the socket should belong to Normally you would use the constant AF _INET as the value of the first argument NOTE AF_NET is declared in the system include file WinSock2 inc The Second Argument The second argument passed to the CreateSocket function is an expression of integer type This argument indicates the kind of socket to create and is normally one of the following constants e SOCK STREAM connection orientated stream socket SOCK_DGRAM connectionless datagram socket SOCK RAW raw socket NOTE These constants are declared in the system include file WinSock2 inc The Third Argument The third argument passed to the CreateSocket function is an expression of integer type This argument indicates the protocol to use for the socket from the address family Normally this argument is zero for all kinds of sockets except raw sockets Return Values The CreateSocket function returns the created socket if the call is successful If the call fails then the value INVALID_SOCKET is returned and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail NOTE INVALID_SOCKET is declared in the system incl
294. nd WSACleanUp functions I winsock2 inc program start output var data WSADATA iRet integer begin iRet WSAStartUp 0202 data if iRet lt gt 0 then begin writeln WSAStartUp call failed Return Code iRet halt end writeln WSAStartUp call succeeded writeln Version hex data wVersion writeln High Version hex data wHighVersion writeln Description data szDescription writeln System Status data szSystemStatus iRet WSACleanUp end Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 4 Cleaning up WinSock2 The WSACleanUp Function Description The WSACleanUp function is used to indicate that your program has finished using the WinSock2 library and should be the last WinSock2 library function your program calls Calling the WSACleanUp function allows the WinSock2 library to free any resources allocated on behalf of your program Any sockets that are open when the WSACleanup function is called are reset and automatically deallocated as if the closesocket function was called Calling the WSACleanup function may result in loss of data if there are sockets that have been closed with the closesocket function but still have pending data to be sent and the call to the WSACleanup function causes the Win
295. nd passed to the ODBC API function SQLConnect to open the connection NOTE The first form of the connection string is the recommended form support for the second form is provided for completeness only Opening MySQL Connections If a MySQL connection is to be opened then the connection string must be in the following form mysql connection string mysql parameter list mysgql parameter list mysql parameter mysql parameter list empty mysql parameter mysql host paramet mysql user paramet mysql password parameter mysql database parameter mysql port parameter mysql socket paramet mysql compress param mp oy th mysgql host parameter host host name mysgql user parameter user user name mysql password parameter password password mysgql database parameter database database name mysql port parameter port port number mysql socket parameter socket Socket mysql compress parameter compress boolean value ysq boolean value yes no true false For example user testuser database testdb socket tmp mysql soc The connection parameters are extracted from the connection string and passed to the MySQL C API function mysql_real_connect to open the connection The effect of each of the parameters is described below The mysql host parameter specifies the hostname or IP address of the MySQL database
296. nect If the time out expires before all data has been sent the Windows Sockets implementation terminates the connection before the closesocket function returns Enabling the SO_LINGER socket option with a nonzero time out interval on a socket with it s non blocking mode enabled is not recommended In this case the call to the closesocket function will fail and the WSAGetLastError function will return WSAEWOULDBLOCK if the close operation cannot be completed immediately However the socket handle is still valid and a disconnect is not initiated Your program must call the closesocket function again to close the socket SO_DONTLINGER Enabled If the SO_DONTLINGER socket option is enabled on a stream socket by setting the _ onoff member of the linger structure to zero the closesocket function call will return immediately and successfully whether the socket has it s non blocking mode enabled or disabled However any data queued for transmission will be sent if possible before the underlying socket is closed This is also called a graceful disconnect In this case the Windows Sockets provider cannot release the socket and other resources for an arbitrary period thus affecting applications that expect to use all available sockets This is the default behavior SO_DONTLINGER is enabled by default Declaration The system include file WinSock2 ine contains the following declarations for the linger type and the closesocket function linger
297. ned by that type The ordinal types are enumerated types integral types and their subranges 5 8 Pointer types Description Pointer types define dynamic collections of values each of which either identifies an instance of the pointer type s domain type or is the special value nil which is guaranteed not to identify any instance Instances of a pointer type s domain type are called identified variables The values of a pointer type s collection can be stored in variables associated with the pointer type called pointer variables The act of using the value stored in a pointer variable to access the identified variable is called dereferencing the pointer variable It is an error to deference a pointer variable which contains the special value nil A pointer variable can be passed to the built in procedure new which will create an identified variable of the same type as the pointer variable s domain type and store the value identifying the identified variable in the pointer variable The value identifying the identified variable is also added to the collection of values defined by the pointer variables type It is an error if an identified variable can not be created because there is not enough available memory A pointer variable can also be passed to the built in procedure dispose which will destroy the identified variable identified by the value stored in the pointer variable The value stored in the pointer variable is also removed fr
298. ned long Parameters With most C compilers the types DWORD unsigned int and unsigned long are unsigned 32 bit integral types so the nearest Irie Pascal type is word Using short Parameters With most C compilers the type short is a signed 16 bit integral type so the nearest Irie Pascal type is shortint Using unsigned short Parameters With most C compilers the type unsigned short is a unsigned 16 bit integral type so the nearest Irie Pascal type is shortword Using Array Parameters Passing multi dimensional arrays between Irie Pascal and C requires care since the ordering used by Pascal and C for the dimensions is opposite i e a array 1 4 1 2 of integer is equivalent to int a 2 4 Using pointer Parameters 1 The C language does not support call by reference so it is common when passing a variable to a function to be modified to pass a pointer to the variable The function can t modify the pointer but it can modify what the pointer is pointing at i e the variable Pascal supports call by reference so you may want to use it in cases where the C function or procedure expects a pointer to a variable 2 The C language also does not support passing arrays to functions however the close relationship between arrays and pointers in C means that passing a pointer to the first element in an array is almost equivalent to passing the array Irie Pascal supports passing arrays so in this case you should pass an array b
299. ngs that every value used in a Pascal program has a type and each value s type controls where and how it can be used One way Pascal controls where and how values can be used is through the concept of assignment compatibility Assignment compatibility is a relationship between values and types and for any given value and type the relationship either exists between them or is does not i e the value is either assignment compatible with the type or it is not Irie Pascal implements the assignment compatibility rules defined by Standard Pascal ISO IEC 7185 and adds one more rule to support variable length string types The first five rules below are taken from ISO IEC 7185 and the sixth one was added to support variable length string types A value V of type T2 shall be designated assignment compatible with a type T1 if any of the following six statements is true T1 and T2 are the same type and that type is not a file type for a type that contains a file type T1 is the real type and T2 is an integral type T1 and T2 are compatible ordinal types and V is in the closed interval specified by the type T1 T1 and T2 are compatible set types and all the members of V are in the closed interval specified by the base type of T1 T1 and T2 are fixed length string types with the same length 6 Tl is a variable length string type and either T2 is a variable length string type or T2 is a fixed length string type or T2 is the char type In addition
300. ngs are repesented in C programs i e null terminated sequences of char The other types such as file and list are not described here because they can not be passed to or from external functions or procedures Most functions in Windows DLLs are written in C so you will usually be converting back of forth between C types and Irie Pascal types NOTE The C types in all capitals like BOOL WORD and DWORD are not actually defined as part of the C language but are common types declared in C programs Using BOOL Parameters The C languages does not define a boolean type so it is common for C programs to define one however there are two popular ways this can be done One way is to define the boolean type as char or unsigned char in which case the nearest Irie Pascal type is byte The other common way to define the boolean type is as a enumerated type with the values FALSE and TRUE However sometimes C compilers treat enumerated types with less than 256 elements as unsigned char and at other times as int the C name for the integer type So if boolean type is defined as an enumerated type then it can either be treated as unsigned char in which case the nearest Irie Pascal type is byte or as int in which case the nearest Irie Pascal type is boolean Using int And long Parameters With most C compilers the types int and long are signed 32 bit integral types so the nearest Irie Pascal type is integer Using DWORD unsigned int And unsig
301. nicating processes to some extent from the details about how the communication is done Programs can basically treat each socket as an end point in a communications link Most programs that use sockets follow a client server model and are either clients or servers The major difference between client and server socket programs is the way in which they establish connections with each other Basically a server socket program creates a socket and then uses this socket to listen for attempts by client socket programs to connect A client socket program on the other hand creates a socket and then tries to connect this socket to the socket created by the server program Once a connection has been established the difference between client and server socket programs becomes less important because data can be sent and received between sockets in both directions Socket Names The term name when applied to sockets means the unique reference used to identify sockets within an address family The elements that make up the name of a socket could vary depending on the address family the socket belongs to Most of the sockets that you are likely to use will belong to the internet address family and their names will be made of the following three elements 1 Address family Identifes the name as belonging to the internet address family 2 Host address IP address e g 127 0 0 1 3 Port number TCP IP port number Socket Types Stream Sockets St
302. nil is returned and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail Example The following procedure was taken from one of the sample programs distributed with Irie Pascal and shows one way to use the gethostbyaddr function PUPOSE Given the IP address of a host perform a reverse DNS lookup 1 strIPAddress contains the name of the host procedure ReverseDNSLookUp strIPAddress cstring var IPAddress in_addr pHostEnt p_hostent begin IPAddress inet_addr addr strIPAddress if IPAddress INADDR_NONE then writeln Invalid IP address else begin pHostEnt gethostbyaddr addr IPAddress sizeof IPAddress AF_INET if pHostEnt nil then writeln Can not find address hex IPAddress else DisplayHostEntInfo pHostEnt end end The procedure DisplayHostEntInfo is defined by the sample program and displays the host information stored in the hostent structure See the gethostbyname function for the actual DisplayHostEntInfo procedure Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 15 1 The shutdown function Description The shutdown function disables the reception of data from a socket and or the transmission of data through a socket
303. not enter 3 command line arguments So far only file type program parameters have been described You can also use string type program parameters They can also access command line arguments but in a different way The command line argument accessed is simply assigned to the string type program parameter If you use program parameters other than file type or string type then the command line argument is ignored The compiler will issue a warning that the command line argument has an invalid type but otherwise do nothing For example look at this rather strange program program strange f sl dummy s2 var f text sl 52 string dummy real begin rewrite f writeln f sl writeln f s2 end If you compile it you will get some warnings but ignore them If you run the program with ivm strange out txt first skip second then the first program parameter f will access out txt and since f is a file type program argument when rewrite is used on f the file out txt will be opened The second program parameter s1 will access first and since this is a string type program argument then first will be assigned to s1 The third program parameter dummy is not a file type or string type program parameter so the third command line argument skip will be ignored The fourth program parameter s2 will access second and since this is a string type program argument then second will be assigned to s2 So the effect of the fo
304. nstance variable as a parameter Syntax The syntax of referencing function and procedure methods and properties is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax function method designator object variable function method identifier actual parameter list procedure method statement procedure method specifier actual parameter list property designator object variable property specifier actual parameter expression variable access procedure identifier function identifier actual parameter list actual parameter actual parameter function method identifier identifier object variable variable access procedure method identifier identifier procedure method specifier object variable procedure method identifier property identifier identifier property specifier property identifier property string property string string expression where object variable is a reference to an object variable and property string is an expression of string type that evaluates to the name of the property being referenced 6 9 Pointer variables Description Pointer variables are used to store values of pointer types These values either identify a variable created by using the built in procedure new on a pointer variable or are the built in value nil which is g
305. nt The sixth argument passed to the recvfrom function is the length of the buffer you supplied to store the name of the socket that sent the data If you supply a buffer to store the name then after the reevfrom function returns successfully this argument will contain the actual length of the name stored in the buffer This argument is ignored when reading from connection oriented sockets Return Values The recvfrom function returns the number of bytes read from the socket if the call is successful If the call fails the value SOCKET ERROR is returned and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail NOTE The constant SOCKET ERROR is declared in the system include file WinSock2 inc If the socket on the other end of the connection has gracefully closed the connection then zero is returned connection oriented sockets only Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 13 1 The send function Description The send function sends data through a socket and can be used on connection oriented sockets e g stream sockets or connectionless sockets e g datagram sockets The behavior of this function may depend on whether the socket has it s non blocking mode enabled or disabled see dealing with
306. nteger type and d integer is compared with the second parameter in a b integer and again they are both value parameters of integer type so Irie Pascal considers the two formal parameter lists to be congruent and therefore the following Operation Add 3 1 is valid 13 6 Allow non numeric statement labels When the allow non numeric statement labels extension is enabled Irie Pascal supports statement labels that look like identifiers i e can contain letters and underscore characters For example in the following program loop is used as a statement label program name output label loop var i integer begin i s 1 loop writeln i i s i 1 if i lt 20 then goto loop end 13 7 Allow underscores in identifiers When the allow underscores in identifiers extension is enabled Irie Pascal supports identifiers which contain and or start with underscore characters i e So for example the following would be valid identifiers _name last_name _all_names_ 13 8 Allow binary and hexadecimal integers When the allow binary and hexadecimal integers extension is enabled Irie Pascal supports integers specified using binary notation and hexadecimal notation In Standard Pascal or when this extension is disabled integers can only be specified using decimal notation 13 9 Auto declare Input and Output Standard ISO IEC 7185 Pascal specifies that whenever the required identifiers input and
307. o Syntax The syntax for constant definition groups is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax constant definition group const constant definition constant definition constant sign integer number sign real number Sign constant identifier character literal string literal constant definition identifier constant 5 1 What are types Types can be defined as groups of values that are related in some way For example the type integer can be defined as the group of whole number values between maxint and maxint Every constant variable parameter and expression in your program is associated with a specific type Irie Pascal defines several built in types that represent commonly used types You can use these built in types or you can define your own You can even redefine the built in types but this is not recommended because it makes your programs more difficult to understand Someone reading your program is likely to assume that the built in types have their normal definition Most types must be defined before they can be used the exceptions to this rule are pointer types and list types Pointer and list types are allowed to be used before they are defined to allow self referencing structures i e structures that point at themselves e g linked lists to be built 5 2 Array types Description Arra
308. o a database with a table named customer 3 The customer table has the fields last_name and first_name new rs rs open conn select last name first name from customer rsforward while not rs eof begin writeln rs field last_name rs field first_name rs movenext end rs close dispose rs First the code fragment creates an instance of a recordset object Next the recordset object is used to open a forward type recordset Next the code loops through all the records contained in the recordset printing out the contents of the fields last_name and first_name Next the recordset is closed Finally the instance of the recordset object is destroyed Portability Operating Systems Al1l Standard Pascal No 5 15 21 2 recordset close Description The close method procedure of the recordset object type is used to close an open recordset Example For example if you have a recordset object reference rs that refers to an open recordset then the following call rs close will close the recordset Portability Operating Systems Al1l Standard Pascal No 5 15 21 3 recordset moreresults Description The moreresults method procedure of the recordset object type is used to to move to the next recordset contained by an open recordset NOTE This method should not to be confused with the movenext method which moves to the next record in the current recordset This method is most often used when calling store
309. o or negative Error Handling This error is always reported 18 48 Integer overflow underflow Official Description 6 7 2 2 It is an error if an integer operation or function is not performed according to the mathematical rules for integer arithmetic Simplified Description This appears to mean that it is an error if integer operations or functions overflow or underflow So for example maxint maxint should be an error since maxint 2 147 486 647 but due to integer overflow maxinttmaxint 2 Error Handling This error is never reported 18 49 Returning undefined value from function Official Description 6 7 3 It is an error if the result of an activation of a function is undefined upon completion of the algorithm of the activation Simplified Description In other words it is an error if the result of a function call is undefined Error Handling This error is reported if checking for undefined values is enabled and the type of the function s result is one of the supported types see Run Time Project Options in the Irie Pascal User s Manual 18 50 Assigning out of range ordinal values Official Description 6 8 2 2 For an assignment statement it is an error if the expression is of an ordinal type whose value is not assignment compatible with the type possessed by the variable or function identifier Simplified Description In other words it is an error to assign an out of range ordinal value to
310. of the function or procedure call 2 Using an assignment statement to assign a value to the variable establishes a reference to the variable starting either before or after the expression on the right hand side of the assignment statement is evaluated and lasting until the value has been assigned to the variable 3 Using the variable in a with statement establishes a reference to the variable that exists during the execution of the statement in the with statement 4 Establishing a reference to a component of the variable also establishes a reference to the variable as a whole So for example it would be an error if you pass a file buffer by reference to a procedure and that procedure performs I O on the file associated with the file buffer Error Handling This error is never reported 18 8 Using out of range value parameters Official Description 6 6 3 2 It is an error if the value of each corresponding actual value parameter is not assignment compatible with the type possessed by the formal parameter Simplified Description In other words when you pass values into formal parameters during a function or procedure call the values must be assignment compatible with the type of the formal parameters into which they are passed If you think about it this makes sense since passing a value into a formal parameter is very much like assigning the value to the formal parameter Error Handling This error is reported if range checking
311. ollowing conn dmver is equal to the version of the ODBC driver manager Portability Operating Systems Al1l Standard Pascal No 5 15 20 10 connection odbcver Description The odbever property of the connection object type contains the version of ODBC that the ODBC driver manager conforms to NOTE If the connection is to a MySQL database then this property always constains an empty string odbever is a read only property of type string Example For example if conn is a connection object reference with an open connection to an ODBC database engine then the following conn odbcver is equal to the version of ODBC that the ODBC driver manager conforms to Portability Operating Systems Al1l Standard Pascal No 5 15 20 11 connection procedures Description The procedures property of the connection object type indicates whether or not stored procedures are supported by the database engine connected to procedures is a read only property of type boolean Example For example if conn is a connection object reference with an open connection to a database engine then the following conn procedures indicates whether stored procedures are supported by the database engine Portability Operating Systems Al1l Standard Pascal No 5 15 20 12 connection readonly Description The readonly property of the connection object type indicates whether or not the connection to the database engine is readonly NOTE
312. om the collection of values defined by the pointer variable s type It is an error to use dispose on a pointer variable containing the special value nil or containing a value that is not in the collection of values defined by the pointer variable s type Example Here are some examples of pointer types integer real Syntax The syntax for defining new pointer types is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax new pointer typ A domain type domain type domain typ type identifier 5 9 Record types Description Record types define collections of values A record type may be empty i e define a collection with no values Each member of a record type s collection is called a field and is identified by a field identifier with the possible exception of the variant selector which sometimes does not have a field identifier Each member in a record s collection has a particular type which can be a record type Sometimes groups of fields in a record type are mutually exclusive in which case you can use variant parts in the record type to specify mutually exclusive groups of fields these mutually exclusive groups are called variants Each variant part contains a variant selector and the value of this variant selector determines which variant if any is active It is an error to access a field of a variant which is not active Example Here are
313. ome blocked if no data is available to be read NOTE When your program is blocked it does not use up any processor cycles and so in the example above being blocked can be a very effecient way for your program to wait until there is data for it to process On the other hand sometimes you will not want your program to ever become blocked This is true if your program must be always responsive For example if your program is a service then it must always be ready to respond to a request to stop Non Blocking Mode Sockets have a non blocking mode that can be enabled or disabled When a socket is created it s non blocking mode is disabled One way to prevent WinSock2 library functions from becoming blocked is to use sockets with non blocking mode enabled If a WinSock2 library function is called on a socket with non blocking mode enabled and conditions are such that the function would block were non blocking mode disabled then instead of becoming blocked the function call will fail If you call WSAGetLastError after the function call fails the return code will be WSAEWOULDBLOCK So for example if you call the recv function to read data from a socket and the socket has non blocking mode enabled and there is no data waiting to be read from the socket then the recv function will return SOCKET _ ERROR to indicate that the call failed If you then call the WSAGetLastError function the error code returned will be WSAEWOULDBLOCK NOTE The constant
314. omponent arrays In other words array 1 10 char boolean of integer is a shorthand notation for array 1 10 of array char of array boolean of integer Example Here are some examples of array types array 1 10 of real array char of boolean array 456 450 of array boolean of integer Syntax The syntax for array types is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax array type array index type list of component type component typ type denoter domain typ type identifier index type ordinal type index type list index type index type new ordinal type enumerated type subrange type new pointer typ A domain type domain type new structured type packed array type packed record type packed set type packed file type packed list type object type string type new typ new ordinal type new structured type new pointer typ ordinal type new ordinal type ordinal type identifier ordinal type identifier identifier type denoter type identifier new typ type identifier identifier 5 3 Enumerated types Description Enumerated types define a finite group of ordered values Each of these ordered values is associated with an identifier an enumerated constant Enumerated constants are ordered b
315. on When the not operator has one operand of boolean type then the result of the operation is true if the value of the operand is false and the result of the operation is false if the value of the operand is true Example not true results in false not false results in true 8 4 5 3 and boolean Description When the and operator has operands of type boolean type then it performs boolean AND The result of the operation is of boolean type and is equal to true of both operands are true and false if either operand is false By default short circuit evaluation is used when performing the boolean AND i e The left operand is evaluated first and if it is false then the right operand is not evaluated because the result of the operation must be false A compiler option can be used to enable disable short circuit evaluation Example false and false results in false false and true results in false true and false results in false true and true results in true 8 4 5 4 and_then boolean Description As an extension to Standard Pascal Irie Pascal supports the and_then operator which takes two operands of boolean type and performs boolean AND The result of the operation is of boolean type and is equal to true of both operands are true and false if either operand is false Short circuit evaluation is always used by the and_then operator i e The left operand is evaluated first and if it is false then
316. on is of boolean type and is true if the left operand is less than or equal to the right operand and false otherwise When the lt operator has two operands of char type or of string type then the char string type conversion rules are applied and then the lexical ordering of the operands are compared The result of this operation is of boolean type and is true if the left operand is less than or equal to the right operand and false otherwise When the lt operator has two operands of set type then it tests for set inclusion The result of this operation is true if all the members of the left operand are in the right operand and false otherwise Example For example 23 lt 23 results in true 23 lt 23 results in true 23 lt 23 0 results in true 23 0 lt 23 results in true 2 lt 3 results in true 2 lt 3 results in false 2 lt 3 results in false 3 lt 2 results in false 3 lt 2 results in true 3 lt 2 results in true and abc lt abc results in true abc lt abc results in true abc lt ab results in false abc lt abd results in true abc lt aac results in false abc lt b results in true and Nar bt Set lt s a returns false rat Dip Set lt hats Tb returns false Vat bt ter lt a n bt te returns true rar lt tat p e returns true at DA lt haty Tp
317. on of the for loop is executed For example given type num 1 100 var n num then the following are errors 1 to 101 do writeln n 100 downto 0 do writeln n for nm 3 for n But the following are not errors since the for loops are never started and therefore no assignments are made to the control variable n for n 1 downto 101 do writeln n for n 100 to 0 do writeln n Error Handling This error is reported if range checking is enabled 18 55 Reading invalid integer values Official Description 6 9 1 On reading an integer from a text file after skipping preceding spaces and end of lines it is an error if the rest of the sequence does not form a signed integer Simplified Description In other words it is an error if the program attempts to read an integer from a text file but the next characters to be read from the text file can not form an integer For example if a text file contains the following ZZZLZLZZZ2Z2 and you try to read in an integer value from this file it is an error Error Handling This error is reported if I O checking is enabled 18 56 Reading out of range integer values Official Description 6 9 1 On reading an integer from a text file it is an error if the value of the signed integer read is not assignment compatible with the type possessed by the variable access Simplified Description In other words it is an error to read an integer value from a text file into a va
318. on or procedure being called to pop the parameters from the stack after the call when the stdeall calling convention is being used but the caller pops the parameters from the stack after the call when the cdecl calling convention is being used e For both calling conventions Irie Pascal searches for the function or procedure in the DLL using the name given but if the function or procedure is not found then _ is prefixed to the name and the DLL is searched again NOTE This is done because some compilers automatically prefix function and procedure names with _ but other compilers don t For both calling conventions Irie Pascal expects function results of ordinal type pointer type or address type to be returned in the EAX register For both calling conventions Irie Pascal expects function results of real type single type or double type to be returned on the math coprocessor stack For both calling conventions Irie Pascal expects function results of record type or array type to be returned using a pointer passed by the caller The caller is expected to pass a pointer to the memory location where the function should put the return value For both calling conventions Irie Pascal does not support returning values of the following types dir file list object set or string from external functions and procedures For both calling conventions Irie Pascal supports passing expressions of the following types by value ordinal types point
319. or is reported if I O checking is enabled 18 12 Writing to middle of file Official Description 6 6 5 2 It is an error if end of file is not true immediately prior to any use of put write writeln or page Simplified Description In other words all file output must take place at the end of files Error Handling Irie Pascal supports output in the middle of a file using the seek procedure and so does not consider this an error and therefore does not report it 18 13 Using Put on undefined buffer variables Official Description 6 6 5 2 It is an error if the buffer variable is undefined immediately prior to any use of put Simplified Description In other words it is an error to use the put procedure to write the contents of a file variable s buffer variable if its contents are undefined Error Handling This error is reported if I O checking is enabled 18 14 Resetting undefined files Official Description 6 6 5 2 It is an error if the file is undefined immediately prior to any use of reset Simplified Description In other words it is an error to use the reset procedure which opens files for reading to open a file if the file does not exist Error Handling This error is reported if I O checking is enabled 18 15 Input from file not open for reading Official Description 6 6 5 2 It is an error if the file mode is not inspection immediately prior to any use of get or read Simplified Descrip
320. or since both case list elements contain 2 Example For example the program fragment below shows an ordinal type and a procedure with a case statement type DayOfWeek monday tuesday wednesday thursday friday saturday sunday procedure WriteDayOfWeek day DayOfWeek begin case day of monday write monday tuesday write tuesday wednesday write wednesday thursday write thursday friday write friday saturday write saturday sunday write sunday end end When the case statement is executed the case index i e day is evaluated and if it is equal to tuesday for example then since the second case list element contains a constant equal to tuesday then the second case list element is choosen and it s statement i e write tuesday is executed Below is a slightly more complex example program example input output var c char begin write Enter a digit readin c case c of TO 9 3 writeln OK a z A Z writeln That is a letter otherwise writeln What is that end end When the case statement is executed the case index i e is evaluated and its value used as follows Ifthe value is a digit then the first case list element is choosen and it s statement i e writeln OK is executed Ifthe value is a letter then the second case list element is choosen and it s statement i e writeln That is a le
321. ore the data to be transmitted If there is no buffer space available within the transport system to store the data to be transmitted then the sendto function will fail and if you then call the WSAGetLastError function to find out the reason for the failure the error code returned will be WSAEWOULDBLOCK You can use the select function to find out when some buffer space becomes available NOTE The constant WSAEWOULDBLOCK is declared in the system include file WinSock2 inc If no local name has been assigned to the socket then a unique local name is assigned to the socket by the system Your program can use the getsockname function to determine the local name assigned to the socket Connectionless Sockets When the sendto function is used on connectionless sockets care must be taken not to exceed the maximum packet size of the underlying provider which can be obtained by using the getsockopt function to retrieve the value of socket option SO_MAX MSG_SIZE If the data is too long to pass atomically through the underlying protocol the sendto function will fail and if you then call the WSAGetLastError function to find out the reason for the error WSAEMSGSIZE is returned and no data is transmitted Declaration The system include file WinSock2 ine contains the following declaration for the sendto function function sendto s SOCKET buf address len flags integer toaddr address tolen integer integer external dll ws2_32 d
322. ored when sending data through connection oriented sockets The Sixth Argument The sixth argument passed to the sendto function is the length of the name of the destination socket or sockets that was specified by the fifth argument This argument is ignored when sending data through connection oriented sockets Return Values The sendto function returns the number of bytes sent through the socket if the call is successful If the call fails the value SOCKET ERROR is returned and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail NOTE The constants SOCKET ERROR WSAEACCES SO_BROADCAST MSG_DONTROUTE MSG_OOB WSAEMSGSIZE and INADDR_BROADCAST are declared in the system include file WinSock2 inc The number of bytes sent through the socket can be less than the number of bytes you are trying to send Also the fact that data has been successfully sent does not guarantee that the data was successfully received Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 14 1 The gethostbyname function Description The gethostbyname function returns information about a host identified by name The host information is returned in a structure of type hostent This structure is allocated by the WinSock2 library and yo
323. ory folder If the directory folder contains files then the rmdir call will fail Parameter The rmdir procedure s only parameter is an expression of string type or char type that is the name of the directory folder to remove Example J 8 KK HK KK I KK A KKK A K K K K K K K K K K K K K a This program removes i e erases a directory First it asks for the name of the directory Then it calls rmdir to remove the directory J RRR KR RK kkk kkk kk kkk kkk k kkk KK k k k kK k k k k k KK k k k k k k k program rd input output var fn filename begin write Which directory do you want to delete readin fn rmdir fn end Portability Operating Systems Al1 Standard Pascal No 7 4 52 The seek procedure Description The seek procedure moves the current file position of a file Parameters 1 The first parameter is a reference to the file variable associated with the file whose current file position is to be moved NOTE The file variable must be open in read only mode or in read write mode 2 The second parameter is an expression of integral type and is the new file position of the file Portability Operating Systems Al1 Standard Pascal No 7 4 53 The setfiledate procedure Description The setfiledate procedure sets the modification date of a file Parameters 1 The first parameter is an expression of string type or char type which is the name of th
324. ot specify whether set elements are present in any partucular order and set elements can not be present more than once All set types define the empty set i e the set value specifying that none of the set elements are present For example the following set type set of boolean defines four values neither false nor true are present false false is present but not true true true is present but not false false true both false and true are present Po Irie Pascal uses two different representations for values of set types depending on the range of the set s base type For example suppose you have the following set type set of T then if T s range is less than or equal to 256 then the set is represented as a bit set otherwise the set is represented using an array representation of fixed size Example Here are some examples of set types set of char set of boolean Syntax The syntax for defining new set types is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax set type set of base type base type ordinal type new ordinal type enumerated type subrange type ordinal type new ordinal type ordinal type identifier ordinal type identifier identifier 5 11 String types Description Fixed Length Strings Irie Pascal supports fixed length strings as defined in Standard Pascal i e fixed length strings wh
325. outines use which global variables and when As a result subroutines can become tightly intertwined making it very difficult to change one subroutine without changing the others Another way to create subroutines that accept input data and or generate output data is to give each subroutine it s own set of special variables to accept input data and store output data These special variables are called parameters When a subroutine is declared a possibly empty list of parameters called formal parameters is specified and within the subroutine the formal parameters are referenced to accept input data and store output data When a subroutine is called the caller must supply the actual data called actual parameters for each formal parameter specified by the subroutine declaration Pascal supports four kinds of formal parameters value parameters variable parameters function parameters and procedure parameters Value parameters are passed by value i e when subroutines with value parameters are called the corresponding actual parameters are expressions and the values of these expressions become the initial values of the value parameters Subroutines reference value parameters just like normal variables and can retrieve and change the value stored in them however changes made to the value stored in value parameters are invisible to the caller Variable parameters are passed by reference i e when subroutines with variable parameters are called
326. output are referenced in a program they must appear as program parameters When the auto declare input and output extension is enabled Irie Pascal does not require that input and output appear as program parameters For example the following program program hello begin writeln Hello end is equivalent to program hello output begin writeln Hello end The first program is not valid in Standard Pascal because the required identifier output is indirectly referenced by the use of the writeln procedure without specifying a file variable but output does not appear as a program parameter 13 10 Allow double quoted literals When the allow double quoted literals extension is enabled Irie Pascal supports character and string literals enclosed with double quotation marks For example you could use Hello world instead of Hello world Double quoted literals can be especially useful if you want to create literals that contain single quotes since you don t have to use two single quotes to represent one single quote For example you could create a string literal containing Don t go away with the following Don t go away instead of Don t do away 13 11 Enable non standard operators When the enable non standard operators extension is enabled Irie Pascal supports the use of non standard operators and the use of standard operators in non standard ways The non standard operators are listed
327. pe is to make database handling more robust by isolating programs to some extent from the specific type of the fields in databases 5 14 1 What are object types Description Object types define dynamic collections of values each of which either identifies an instance of an object described by the object type or is the special value nil which is guaranteed not to identify any instance of an object The values in object type collections are stored in variables associated with the object type called object references These object references can be used to refer to or access the object instance identified by the value stored in the object reference Object instances have properties which are similiar to the fields in records and methods Method are functions or procedures that define what the object can do and also what can be done to the object Irie Pascal does not currently fully support object types in particular Irie Pascal does not allow you to define your own object types You are restricted to using the built in object types connection and recordset or using the generic object type The built in procedure new can be used to create an instance of one of the built in object types and store the value identifying the instance in an object reference This also adds the identifying value to the collection of values defined by the built in object type associated with the object reference The built in procedure new can not be used to cr
328. pe to perform bitwise NOT The result of the operation is calculated by flipping all the bits in the operand Example not 1 results in 2 Since not 1 not 00000000000000000000000000000001 which results in 11111111111111111111111111111110 or 2 8 4 8 3 and bitwise Description As an extension to Standard Pascal Irie Pascal supports using the and operator with two operands of integral type to perform bitwise AND The result of the operation is of integral type and has its bits set as follows each bit is one 1 in the result if and only if the both of the bits in the corresponding position in the operands are one 1 Example 11100 and 10111 results in 10100 Binary notation is used in the example above so that you can clearly see the individual bits in the operands and the result The example above could have been written as 28 and 23 results in 20 which is the same thing but is probably not as clear 8 4 8 4 or bitwise Description As an extension to Standard Pascal Irie Pascal supports using the or operator with two operands of integral type to perform bitwise OR The result of the operation is of integral type and has its bits set as follows each bit is one 1 in the result if and only if one of the bits in the corresponding position in the operands is one 1 Example 11100 or 10111 results in 11111 Binary notation is used in the example above so that you can clearly see the individual
329. perating system address of the buffer that you have supplied to store the data read from the socket The type of this argument is address which means that you must use the built in function addr to pass the operating system address of the buffer The Third Argument The third argument passed to the reevfrom function is the length of the buffer you have supplied to store the data read from the socket The Fourth Argument The fourth argument passed to the reevfrom function can specify flags which influence the behavior of the recvfrom function The flags can be OR d or added together if more than one flag is being specified The flags which can be used are MSG PEEK Peeks at the data in the socket The data is copied from the socket into the buffer supplied but is not removed from the socket When this flag is used the reevfrom function returns the number of bytes of data waiting available to be read MSG_OOB Read OOB data from the socket If you do not wish to specify any flags then use zero as the value of this argument The Fifth Argument The fifth argument passed to the reevfrom function is optional and should either be zero or the operating system address of a buffer to store the name of the socket that sent the data If you are passing the operating address of a buffer then you should use the built in function addr to get this address This argument is ignored when reading from connection oriented sockets The Sixth Argume
330. plied is an expression of integral type which specifies permissions for the directory folder being created The permission constants can be used to specify directory folder permissions If this parameter is not supplied then the default permissions are used NOTE Some operating systems like Windows ignore this parameter Example The following call to create the directory folder e irie test will fail if the directory folder e irie does not already exist mkdir irie test makes the directory test in the directory irie Portability Operating Systems Al1l Standard Pascal No 7 4 32 The move procedure Description The move procedure copies memory from one memory address to another The memory is copied correctly even if the source and destination memory locations overlap Parameter 1 The first parameter is a reference to a variable that specifies the source memory address i e the address of the first byte to be copied If the variable is of address type or of pointer type then the address stored in the variable is the source memory address If the variable is not of address type or of pointer type then the address of the variable itself is the source memory address 2 The second parameter is a reference to a variable that specifies the destination memory address i e the address where the memory is to be copied If the variable is of address type or of pointer type then the address stored in the variable is the destination
331. printable keys from the keyboard buffer The first call to this function returns chr 0 and the second call returns the scan code for the key Parameter None Portability Operating Systems Windows Standard Pascal No 7 2 53 The reverse function Description The reverse function returns a value of type string that is formed by reversing the order of the characters in the parameter passed to it The type of the value returned by this function is always string Parameter The reverse function s only parameter is an expression of string type or char type Example reverse Hello returns olleH Portability Operating Systems Al1 Standard Pascal No 7 2 54 The round function Description The round function rounds the parameter passed to it i e returns the integer number that is closest in value to the parameter The type of the value returned by this function is always integer Parameter The round function s only parameter is an expression of real type Example round 7 4 returns 7 round 7 5 returns 8 round 7 4 returns 7 round 7 5 returns 8 Portability Operating Systems Al1l Standard Pascal Yes 7 2 55 The sin function Description The sin function returns the sine of the parameter passed to it The type of the value returned by this function is always real Parameter The sin function s only parameter is a numeric expression i e an expression of integral type or of real type wh
332. procedure The seek procedure The setfiledate procedure The setfiletime procedure The sleep procedure The str procedure The textbackground procedure The textcolor procedure The traperrors procedure The val procedure The standard procedures that can be used in non standard ways are listed below The reset procedure The rewrite procedure 14 1 Deviations from ISO IEC 7185 Irie Pascal complies with the requirements of level 0 of Standard Pascal i e ISO IEC 7185 with the following exceptions end of line char Termination of all lines in text files new p cl cN dispose q k1 kM Carriage returns ISO IEC 7185 is the standard for the Pascal porgramming language published by the Internation Organization for Standardization 14 2 end of line char Standard Pascal requires that end of line characters read from text files be converted to spaces For example given read f c where f is a text file at end of line and is a character variable then according to Standard Pascal after the read above c should contain a space character rather than an end of line character Irie Pascal does not convert end of line characters read from text files so in the example above e will contain an end of line character i e a linefeed character chr 10 14 3 Termination of all lines in text files Standard Pascal requires that all lines in text files except possibly the line that is currently b
333. procedure b is declared You can try to correct this problem by moving the declaration of procedure b before the declaration of procedure a like so lt Ne program test output procedure b x integer begin writeln x a xt 1 end procedure a x integer begin writeln x b xt 1 end begin a 1 end but if you try to compile this program the the compiler will now complain about the call to a x 1 that occurs in procedure b because this call now occurs before procedure a is declared The solution to this problem is to use the forward directive as illustrated by the program below program test output r procedure b x integer forward procedure a x integer begin writeln x b x 1 end procedure b begin writeln x a x 1 end begin a 1 end See the forward directive for more information As an extension to Standard Pascal Irie Pascal supports calling functions and procedures inside Windows DLLs using the external directive See the external directive for more information Syntax The syntax for function and procedure declarations is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax unction declaration unction heading directive unction identification function block unction heading function block Fh Fh Fh Fh rocedure declaration rocedure heading
334. r sign unsigned constant sign variable access sign expression sign function designator sign function method designator sign not factor field designa field designa set constructor tor identifi tor record variable gt name lational operator shift expression stdeall cdecl r identifier field specifier i ld designator identifier fField identifier identifier fField list fixed part variant part fixed part variant part field specifier field identifier file type file of component type file variable variable access final value ordinal expression fixed part record section record section for statement for control variable initial value to downto final value do statement formal parameter list formal parameter section formal parameter section formal parameter section value parameter specification variable parameter specification procedure parameter specification function parameter specification forward directive forward fractional part digit sequence Function block block function declaration function heading directive Function identification function block Function heading function block fFunction designator function identifier actual parameter list function heading f
335. r integer or real depending on whether the optional parameter is supplied Parameter The random function s optional parameter is an expression of integral type If this parameter is supplied then the value returned by this function is a random integer between zero and the value of the parameter minus i e if the value of the parameter is I then the value returned by this function is a random integer between zero and I 1 If the parameter is not supplied then the value returned by this function is a random real number between zero and one Example random 10 returns a random integer between 0 and 9 random returns a random real number between 0 and 1 Portability Operating Systems Al1l Standard Pascal No 7 2 52 The readkey function Description The readkey function returns the next key in the keyboard buffer If there are no keys in the keyboard buffer then this function waits until a key is pressed You can use the keypressed function to check the keyboard buffer for keys before calling this function The type of the value returned by this function is always char If the next key in the keyboard buffer corresponds to a printable character then this function simply returns the character however if the key does not correspond to a printable character e g Page Up then this function actually returns two characters on separate calls to this function In other words this function has to be called twice to completly read non
336. r 13 is CARRIAGE RETURN isspace A returns false isspace 6 returns false isspace S returns false Portability Operating Systems Al1l Standard Pascal No 7 2 34 The isupper function Description The isupper function returns a value of type boolean which indicates whether the parameter passed to it is a uppercase alphabetic character If the parameter is a uppercase alphabetic character then the value true is returned and if the parameter is not a uppercase alphabetic character then the value false is returned Parameter The isupper function s only parameter is an expression of char type Example isupper a returns false isupper A returns true isupper 1l returns false isupper returns false isupper returns false Portability Operating Systems All Standard Pascal No 7 2 35 The isxdigit function Description The isxdigit function returns a value of type boolean which indicates whether the parameter passed to it is a hexadecimal digit character i e 0 9 and a f and A F If the parameter is a hexadecimal digit character then the value true is returned and if the parameter is not a hexadecimal digit character then the value false is returned Parameter The isxdigit function s only parameter is an expression of char type Example isxdigit a returns true isxdigit A returns true isxdigit h returns false isxdigit l returns true isxdigit
337. r_ list address end p_hostent hostent function gethostbyaddr addr address len typ integer address external dll ws2_32 d11 Arguments The First Argument The first argument passed to the gethostbyaddr function is the operating system address of the buffer containing the address of the host you want to get information about The address stored in the buffer is not stored as a string it is stored as a numeric value in in network byte order The type of this argument is the built in type address so you must use the built in function addr to get the operating system address of the buffer If you have the address of a host as a null terminated string and you want to get information about that host then you should do the following 1 Use the inet_addr function to convert the address represented as a string into an address represented in a numeric format 2 Use the gethostbyaddr function to get the host information The Second Argument The second argument passed to the gethostbyaddr function is the length of the host address in the buffer pointed to be the first argument The Third Argument The third argument passed to the gethostbyaddr function is the type of the host address in the buffer pointed to be the first argument Return Values The gethostbyaddr function returns a pointer to the hostent structure that contains the host information if the call is successful If the call fails then the value
338. ream sockets are connection oriented and must be in a connected state i e they must have established a connection to another socket before any data can be sent or received A connection to another socket is created with a call to the connect function Once connected data can be transferred between the sockets using the send sendto recv and recvfrom functions Datagram Sockets Datagram sockets are not connection oriented and are used to send and receive blocks of data called datagrams In order to send datagrams both the source socket and the name of one or more destination sockets must be specified The sendto function which allows you to specify both a source socket and the name of one or more destination sockets is normally used to send datagrams The send function can also be used to send datagrams however because the send function does not allow you to specify the name for the destination datagram socket or sockets the name of the destination datagram socket or sockets must have been previously specified by the connect function The recvfrom function can be used to receive datagrams and can optionally return the name of the socket that sent the datagram The recv function can also be used to receive datagrams however the connect function must have been used previously to specify the name for the source datagram socket or sockets Reference Information As you might expect the internet is an excellent source of
339. regs wordregs registers record case regtype of byteregs al ah afilll afill2 byte bl bh bfilll bfill2 byte cl ch cfilll cfill2 byte dl dh dfilll dfill2 byte wordregs eax ebx end Example si edi cflag word The simple program below clears the screen by using the built in procedure intr to call the BIOS INT 10 interrupt program cls var regs registers begin fill regs 0 regs eax 0002 intr 10 regs end Portability Operating Systems Al1 Standard Pascal No Description 5 15 14 regtype type regtype is the type identifier for a built in enumerated type which is part of the variant record type which is used to store the x86 processor registers before and after calls to the built in procedure intr The variant record layout is given below si edi cflag word regtype byteregs wordregs registers record case regtype of byteregs al ah afilll afill2 byte bl bh bfilll bfill2 byte el ch cfilll cfill2 byte dl dh dfilll dfill2 byte wordregs eax ebx cx edx end Example The simple program below clears the screen by using the built in procedure intr to call the BIOS INT 10 interrupt program cls var regs registers begin fill regs 0 regs eax 0002 intr 10 regs end Portability Operating Systems Al1 Standard Pasca
340. rent diectory using the built in procedure exec Basically the program determines whether it is running under a Unix like platform or not and passes the approprate list command to exec along with the pas argument so that only files ending with pas are listed program dirpas output const UnixListCommand ls l OtherListCommand dir begin if UnixPlatform then exec UnixListCommand pas else exec OtherListCommand pas if exitcode lt gt 0 then writeln Error listing directory exitcode end Portability Operating Systems Al1l Standard Pascal No 7 4 16 The exit procedure Description The exit procedure terminates the program or the function or procedure in which it is used and optionally may return a value to the caller If used in a function then the exit procedure terminates the function If used in a function named f then exit e is equivalent to f e exit If used in a procedure then exit terminates the procedure If used in a procedure then exit x is invalid since you can not return a value from a procedure If used in the main program then exit terminates the program If used in the main program then exit e is equivalent to ExitCode e exit i e the program is terminated with e as the exit code Parameter The exit procedure s only paramter is an expression If supplied this parameter is the
341. repea simple statement empty sta procedure statement proced tatement sequenc t statement cement until boolean expression while statement for statement jassignment statement ure method statement goto statement statement sequence statement statement structured statement compound statement conditional statement repetitive statement with statement while statement while boolean expression do statement with statement with record variable list do statement 9 2 Empty statement Description Empty statements don t perform any action and are usually created when the rules of Pascal require a statement to exist but you don t specify one For example if you write begin end then technically according to the rules of Pascal there must be a statement between the begin and the end and since there is nothing there the empty statement is said to exist there Empty statements also commonly occur when statement sequences have a trailing semi colon In Pascal the semi colon is used as a statement separator and not a statement terminator so the following statement sequence a b actually contains three statements the statement a the statement b and an empty statement following b Since a semi colon follows b then it must separate b from another statement Syntax mpty statement 9 3 Assignment statement Description
342. riable if the integer value is not assignment compatible with the type possessed by the variable Error Handling This error is reported if range checking is enabled 18 57 Reading invalid numeric values Official Description 6 9 1 On reading a number from a text file after skipping preceding spaces and end of lines it is an error if the rest of the sequence does not form a signed number Simplified Description In other words it is an error if the program attempts to read an integer value or a real value from a text file but the next characters to be read from the text file can not form an integer value or real value For example if a text file contains the following ZZZZLZZ22 and you try to read in an integer value or real value from this file it is an error Error Handling This error is reported if I O checking is enabled 18 58 Reading when file is not open Official Description 6 9 1 It is an error if the buffer variable is undefined immediately prior to any use of read Simplified Description This apparently means that it is an error to read from a file that is either not open or has been opened for writing Error Handling This error is reported if I O checking is enabled 18 59 Writing with TotalWidth or FracDigits less than one Official Description 6 9 3 1 On writing to a textfile the values of TotalWidth and FracDigits are greater than equal to one it is an error if either value is less than one
343. ring type the relational operators compare the lexical ordering of the operands For operands of set type the relational operators lt and gt only test whether one operand is a subset of the other 8 4 4 2 Is less than Description The lt operator takes two operands and compares them If the operands are numeric then the numeric type conversion rules are applied before the comparision is done If the operands are of char type or of string type then the char string type conversion rules are applied before the comparision is done The result of this operation is of boolean type and is true if the left operand is less than the right operand and false otherwise Example For example 23 lt 23 results in false 23 lt 23 results in false 29 lt 23 0 results in false 23 0 lt 23 results in false 2 x 3 results in true 2 lt 3 results in false 2 lt 3 results in false 3 x 2 results in false 3 lt 2 results in true 3 lt 2 results in true and abc lt abc results in false abc lt abcd results in true abc lt ab results in false abc lt abd results in true abc lt aac results in false abc lt b results in true 8 4 4 3 Is less than or equal Description When the lt operator has two numeric operands it compares their values after applying the numeric type conversion rules The result of this operati
344. riteln High Version hex data wHighVersion writeln Description data szDescription writeln System Status data szSystemStatus iRet WSACleanUp end Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 5 Checking for errors The WSAGetLastError Function Description The WSAGetLastError function retrieves the error code for the last unsuccessful call to a WinSock2 library function Most WinSock2 library functions indicate failure by returning a particular value and you have to call the WSAGetLastError function to find out the reason for the failure The error code returned by this function is not effected by calls to WinSock2 library functions that succeed or by calling this function to retrieve the error code An error code of zero means that no WinSock2 library function has failed since you initialized the WinSock2 library i e called the WSAStartUp function or since you last set the error code to zero by calling the WSASetLastError function Declaration The system include file WinSock2 ince contains the following declaration for the WSAGetLastError function function WSAGetLastError integer external dll ws2_32 d11 Arguments None Return Values See Description Reference Information The authoritative source of information about th
345. rograms distributed with Irie Pascal and demonstrates how to connect a socket to a listening socket PURPOSE Connects a client data socket PARAMETER s 1 s The socket to be connected 2 port The TCP IP port to connect the socket to 3 a The IP address to connect the socket to procedure ConnectDataSocket s socket port integer a in_addr var sa sockaddr_in iRet integer begin ConnectDataSocket fill sa 0 sa sin_family AF_INET sa sin_port htonl port shr 16 sa sin_addr a iRet connect s addr sa sizeof sa if iRet lt gt 0 then FatalSocketError Call to connect failed end ConnectDataSocket Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 12 1 The recv function Description The recv function reads data from a socket and can be used on connection oriented sockets e g stream sockets or connectionless sockets e g datagram sockets If there is no data available to be read from the socket then what happens next depends on whether the socket has it s non blocking mode enabled or disabled see dealing with blocking for more information about the non blocking mode of sockets Non blocking mode disabled If the socket has it s non blocking mode disabled and there is no data ava
346. rror Handling This error is always reported 18 34 In x and x is less than or equal to 0 Official Description 6 6 6 2 For In x it is an error if x is not greater than zero Error Handling This error is always reported 18 35 Square root of negative number Official Description 6 6 6 2 For sqrt x it is an error if x is negative Error Handling This error is always reported 18 36 Problems with trunc Official Description 6 6 6 3 For trunc x the value of trunc x is such that if x is positive or zero then 0 lt x trunc x lt 1 otherwise 1 lt x trunc x lt 0 It is an error if such a value does not exist Simplified Description In other words it is an error to use the trunc function to convert a value of real type into a value of integral type if the real value is outside the range of integral values supported by Irie Pascal For example trunc 1 0e16 is an error Error Handling This error is never reported 18 37 Problems with round Official Description 6 6 6 3 For round x if x is positive or zero then round x is equivalent to trunce x 0 5 otherwise round x is equivalent to trunc x 0 5 It is an error if such a value does not exist Simplified Description In other words it is an error to use the round function to convert a value of real type into a value of integral type if the real value is outside the range of integral values supported by Irie Pascal For example round 1 0e16 is
347. rst call in a variable New programs should use getlasterror instead of ioresult which dispite it s name also returns all trappable errors not just I O errors ioresult continues to be supported for compatibility reasons only Parameter None Example For example the following is incorrect if getlasterror lt gt 0 then case getlasterror of 1 writeln Error erasing file 2 writeln Error renaming file 3 writeln File is undefined since the second call to getlasterror will always return 0 Instead you should do something like this errnum getlasterror if errnum lt gt 0 then case errnum of 1 writeln Error erasing file 2 writeln Error renaming file 3 writeln File is undefined end Portability Operating Systems Al1l Standard Pascal No 7 2 24 The hex function Description The hex function returns the hexadecimal value of the parameter passed to it The type of the value returned by this function is always string Parameter The hex function s only parameter is the expression of integral type whose value is to be converted to hexadecimal Example hex 10 returns A hex 16 returns 10 hex 255 returns FF Portability Operating Systems Al1l Standard Pascal No 7 2 25 The int function Description The int function returns the integral part of the parameter passed to it The type of the value returned by this function is
348. s 16 3 Provision of tokens and delimiting characters 16 4 Size and precision of real val 16 5 Character set 16 6 Ordinal values of characters 16 7 Characters prohibited from text files 16 8 When I O is performed 16 9 Value of maxint 16 10 Accuracy of real operations and functions 16 11 Default value of TotalWidth for integer type 16 12 Default value of TotalWidth for real type 16 13 Default value of TotalWidth for boolean type 16 14 Number of digits written in exponent 16 15 Use of e or E as exponent character on output 16 16 Case of characters used on output of boolean values 16 17 Effect of built in procedure page 16 18 Binding of file type program parameters 16 19 Effect of reset and rewrite on input and output 17 Appendix E Implementation dependent features 17 1 Implementation dependent features 17 2 Effect of writing prohibited characters 17 3 Order of evaluation of index expressions 17 4 Order of evaluation of expressions of a member designator 17 5 Order of evaluation of member designators 17 6 Order of evaluation of operands of dyadic operators 17 7 Order of evaluation of actual parameters for function calls 17 8 Order of evaluating components of assignment statements 17 9 Order of evaluation of actual parameters for procedure calls 17 10 Effect of reading a text file to which page has been applied 17 11 Binding of non file program parameters 18 Appendix F Errors 18 1 What are errors 18 2 Array index out of boun
349. s are not supported sql tc dml Transactions containing Data Manipulation Language DML statements are supported Transactions containing Data Definition Language DDL statements cause an error DML statements include SELECT INSERT UPDATE DELETE DDL statements include CREATE and DROP sql tc all Transactions containing both DML and DDL statements are supported sql tc ddl commit Transactions containing DML statements are supported DDL statements encountered in transactions cause the transactions to be committed sql tc ddl ignore Transactions containing DML statements are supported DDL statements encountered in transactions are ignored Portability Operating Systems Al1l Standard Pascal No 5 15 21 1 The recordset type Description recordset is the type identifier for a built in object type whose values identify instances of recordset objects Instances of recordset objects are used to retrieve groups of records from open database connections The recordset object type has four methods recordset close recordset moreresults recordset movenext e e recordset open The recordset object type has two properties recordset eof recordset field Example The code fragment below show a typical use of a recordset NOTE The code fragment is not a complete program and makes the following assumptions 1 conn is an connection object reference for an open connection object 2 conn is connected t
350. s are readable or writeable and or checks one or more sockets for errors A socket is readable if it is a data socket and data is available for reading therefore the recv or recvfrom functions will not block itis a data stream socket and a request to close the connection has been received from the socket at the other end of the connecion therefore the recv function will return immedietly and not block itis a listening socket and a connection request is pending therefore the accept function will not block A socket is writeable if itis a data socket and data can be sent therefore the send or sendto functions will not block the socket s non blocking mode is enabled and a connection request from this socket has been accepted NOTE If you call the connect function on a socket and the socket has it s non blocking mode enabled then connect will not wait for the connection request to be accepted by the socket at the other end Instead the connect function will return SOCKET ERROR immediately as if the call failed however the connection request will still be pending the request will be queued by the listening socket at the other end The socket will become writeable if the connection request is accepted The errors that the select function can detect are e The connect function was called on a socket and the socket has it s non blocking mode disabled but the connection request was not accepted OOB
351. s being used to store the values read from the text file then a sequence of characters forming a signed decimal integer number possibly with leading blanks is read from the file and converted into the equivalent value of integer type before being stored in the variable Ifa variable of real type single type or double type is being used to store the values read from the text file then a sequence of characters forming a signed real number possibly with leading blanks is read from the file and converted into the equivalent value of real type before being stored in the variable Reading From Non Text Files If the read procedure reads values from a non text file i e a file associated with a file variable that is not of type text then the type of the values read from the file is the same as the type of the variables used to store the values and this type is usually the same as the file type s component type The values are read from the file and stored in the variables without conversion Example read f xX Y Z reads three values from the file associated with wen into maet tyy and WoW Portability Operating Systems Al1 Standard Pascal Yes Standard Pascal does not support reading from text files into variable of string type 7 4 45 The readdir procedure Description The readdir procedure reads a filename from a directory variable 1 e retrieves the name of the next file in the directory associated with the direc
352. s declared in the system include file WinSock2 inc Example The following function uses the select function to check whether a socket is readable function IsSocketReadable s SOCKET iMaxWaitSecs iMaxWaitUSecs integer boolean var s_set fd_set tv timeval iRet integer begin IsSocketReadable Put socket in the set of sockets to be tested s_set fd_count 1 s_set fd_array 0 s Specify the maximum wait time tv tv_sec iMaxWaitSecs tv tv_usec iMaxWaitUSecs Check whether socket is readable iRet select 0 s_set null null tv IsSocketReadable iret 1 end IsSocketReadable Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 10 1 The accept function Description The accept function allows a listening socket to establish a connection The underlying network service provider will queue up requests to connect to the listening socket and this function will extract the first connection request from the queue You can specify the maximum size of the connection request queue when you put the socket in istening mode i e when you call the listen function Non blocking mode disabled If the listening socket has it s non blocking mode disabled which is the default condition and no connection reques
353. s generated by Irie Pacal calculate the address of the variable before the expression is evaluated 17 9 Order of evaluation of actual parameters for procedure calls 6 7 3 The order of evaluation accessing and binding of the actual parameters of a procedure statement is implementation dependent In other words the order in which the actual parameters are evaluated and passed to the formal parameters during a procedure call is implementation dependent Irie Pascal evaluates and passes actual parameters from left to right 17 10 Effect of reading a text file to which page has been applied 6 9 5 The effect of inspecting a text file to which the page procedure was applied during generation is implementation dependent Applying page to a text file during generation causes a form feed character i e chr 12 to be written to the file During inspection i e when the text file is read the handling of the form feed character depends on the type of data the program is trying to read If the program is trying to read in integer or real data then the form feed character is treated like a space character and is therefore skipped If the program is trying to read in character or string data then the form feed character is read in like any other character 17 11 Binding of non file program parameters 6 10 The binding of the non file variables denoted by the program parameters to entities external to the program is implementation dependent See
354. s in the line to be written to the file Example writeln true writes true writeln true 2 writes tr writeln 3567 writes 3567 writeln 3567 1 writes 3567 writeln 1 2345678 writes 1 23E 00 writeln 1 2345678 8 writes 1 2E 00 writeln 1 2345678 8 3 writes 1 235 Portability Operating Systems Al1l Standard Pascal Yes 7 5 1 Procedure declarations Description Procedure identifiers are identifiers that have been associated with a procedure using a procedure declaration Example Here is an example of a procedure declaration FERRE RK AK KKK KK KKK KKK KKK KKK KKK KKK KK KKK KKK KKK KK KEK KKK KK KKK KEK KEK KEKE KK PURPOSE Writes the contents of one file into another ARGUMENTS ER f the input file Ek g the output file NOTES It is up to the caller to open and close the files procedure WriteFile var f g text var c char begin while not eof f do begin read f c write g c end end Syntax NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax procedure declaration procedure heading directive procedure identification procedure block procedure heading procedure block block declarative part statement part compound statement begin statement sequence end declaration group labe
355. s limit the compiler issues a fatal error message The second limit is more specific and limits the maximum depth to which the following kinds of statements can be directly or indirectly nested inside each other Case statements e For statements With statements This second limit is 20 If you exceed this limit the compiler issues a error message and continues 15 11 Nesting of include directives Irie Pascal limits the depth to which files can be included into each other This limit is 30 NOTE Files can be included into each other using the include compiler directive The syntax for the include compiler directive is I name or I name where name is the name of the file to include into the current file 15 12 Stack size The default stack size is 64K but you can adjust this to any value from 1K to 1024K 1MB using the Code Generation Page of the Project Options dialog If you exceed this limit the compiler will issue an error message 15 13 Number of Source Lines Irie Pascal limits the maximum number of source lines that can be compiled to 4 294 967 295 If you exceed this limit the compiler will issue a fatal error message 16 1 Implementation defined features The Pascal Standard ISO IEC 7185 says that some features of the Pascal language are implementation defined ISO IEC 7185 further says that each implementation called a processor by ISO IEC 7185 must provide a definition of all implementation defined f
356. s specified by ISO IEC 7185 13 1 What are extensions 13 2 Allow relax laration 13 3 Allow constant ranges 13 4 Allow otherwise 13 5 Allow relaxed parameter list congruity 13 6 Allow non numeric statement labels 13 7 All nderscores in identifier 13 8 Allow binary and hexadecimal integers 13 9 Auto declare Input and Output 13 10 Allow double quoted literals 13 11 Enable non standard operators 13 12 Enable non standar nstant 13 13 Enable non standard types 13 14 Enable non standard variables 13 15 Enable non standard functions 13 16 Enable non standard procedures 14 Appendix B Deviations from ISO IEC 71 14 1 Deviations from ISO IEC 7185 14 2 end of line char 14 3 Termination of all lines in text files 14 4 new p cl cN 14 5 di k1 kM 14 6 dispose pointer value 14 7 Carriage returns 15 Appendix C Implementation limits 15 1 Implementation limits 15 2 Length of source lines 15 3 Numter and nesting of statement sequences 15 4 Nesting of functions procedures 15 5 Range of variant selector s type amp Number of variants 15 6 Size of integer constants 15 7 Size of real constants 1 ize of nd dat 15 9 Number of set elements 15 10 Nesting of statements 15 11 Nesting of include directives 15 12 Stack size 15 13 Number of Source Lines 16 Appendix D Implementation defined features 16 1 Implementation defined features 16 2 String element
357. s that the data sent should not be subject to routing This flag may be ignored MSG OOB Sends OOB data through the socket If you do not wish to specify any flags then use zero as the value of this argument Return Values The send function returns the number of bytes sent through the socket if the call is successful If the call fails the value SOCKET ERROR is returned and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail NOTE The constant SOCKET ERROR is declared in the system include file WinSock2 inc The number of bytes sent through the socket can be less than the number of bytes you are trying to send Also the fact that data has been successfully sent does not guarantee that the data was successfully received at the other end Example The following procedure is taken from the sample program wSpamFilter and uses the send function to send data through a socket The type LineType is a cstring type A CR LF pair is appended to the end of the data because the server at the other end expects it and is not a requirement for using the send function PURPOSE Writes and logs a line to the data socket PARAMETER s 1 buffer Contains the data to write to the socket NOTES A CR LF pair is appended to the line before writing to the socket procedure WriteDataSocket var buffer LineType var iRet integer begin WriteDataSo
358. scription feature_readdir can be used to determine if the current platform supports the built in procedure readdir Example if supported feature closedir and supported feature readdir and supported feature opendir then begin open directory retrieve filenames and then close directory end else begin Opening reading and closing directories are not supported so do something else of abort end Portability Operating Systems Al1l Standard Pascal No 4 2 18 feature_readkey readkey supported Description feature_readkey can be used to determine if the current platform supports calling the built in function readkey Example if not supported feature readkey then begin writeln readkey not supported on the current platform abort end Portability Operating Systems Al1l Standard Pascal No 4 2 19 feature_rewinddir rewinddir supported Description feature_rewinddir can be used to determine if the current platform supports the built in procedure rewinddir Example if supported feature rewinddir then rewinddir Portability Operating Systems Al1l Standard Pascal No 4 2 20 feature_textbackground textbackground supported Description feature_textbackground can be used to determine if the current platform supports the built in procedure textbackground Example program color output const blue 1 white 15 begin x if supported
359. se engines currently connections can only be made via ODBC or to MySQL databases The connection object type has the following methods connection close connection execute connection open connection selectdatabase The connection object type has the following properties connection databasename connection dbmsname connection dbmsname connection dmver connection odbcver connection procedures connection readonly connection transactions connection transsupport The built in procedure new is used to create instances of connection objects and the built in procedure dispose is used to detroy instances of connection objects Example The simple program below illustrates how to connect to a database engine using the connection object type program Data input output var conn connection procedure DisplayError msg string begin writeln ERROR msg halt end function GetConnectionString string var s sDSN SUSER sPassword string function GetStringValue sPrompt string string var sValue string begin write sPrompt readin sValue GetStringValue sValue end begin if supported feature odbc then begin sDSN GetStringValue Enter Data Source Name DSN sUser GetStringValue Enter user id sPassword GetStringValue Enter password s ODBC DSN sDSN user sUsert password s
360. ser s Manual e V A flag directive that controls checking for accessing inactive record variants See record types for more information on record variants See also the v compiler option for the command line compiler for more information documented in the User s Manual e W A flag directive that controls whether the compiler issues warnings or not All of the compiler directive can be used as flag directives and in this case the compiler directive instructs the compiler to turn an option on or off When a compiler directive is used as a flag directive the INFORMATION part of the compiler directive is one of the following symbols Turns the compiler option on Turns the compiler option off Returns the compiler option to its previous setting before the last change The compiler displays an error if there is no previous setting for the compiler option So for example the following compiler directive R turns range checking off The I compiler directive can be used to instruct the compiler to include a file inside the current file In this case the INFORMATION part of the compiler directive is the name of the file to include For example SI windows inc The W compiler directive can be used to instruct the compiler to turn off or on individual warning messages So for example SW44 can be used to turn off the warning about lt X gt is never used before including a file which declares many identit
361. set Portability Operating Systems Al1l Standard Pascal Yes 7 2 44 The paramcount function Description The paramcount function returns the number of arguments passed to the program The type of the value returned by this function is always integer Parameters None Example For example the following is a simple program args pas that uses the paramcount function to display the number of arguments passed to it program args output begin writeln Number of program arguments paramcount end If you run the program with four arguments like below ivm args this is a test then the output would be Number of program arguments 4 since four arguments were passed to the program l this is 3 a 4 test Portability Operating Systems All Standard Pascal No 7 2 45 The paramstr function Description The paramstr function returns one of the arguments passed to the program The parameter passed to this function is the number of the argument to return The type of the value returned by this function is always string Parameter The paramstr function s only parameter is the expression of integral type whose value is the number of the program argument to return 1 e if the parameter is N then this function will return the Nth program argument If there is no Nth program argument then an empty string is returned If the value of the parameter is zero then the name of the program is returned If the value of
362. sing all of the constants const black 0 blue 1 green 2 r3 H ct 0 Normal background textbackground blue blinking write Blinking blue background textbackground black writeln Normal background Portability Operating Systems Windows only Standard Pascal No 7 4 58 The textcolor procedure Description The textcolor procedure sets the current text foreground color Calling this procedure does not immediately change the foreground color of the screen The foreground colors of characters already on the screen are not changed what this procedure does is to change the foreground color of characters written to the screen after the procedure is called The following table shows the values used to specify various foreground colors value color 0 Black 1 Blue 2 Green 3 Cyan 4 Red 5 agenta 6 Brown 7 vhite 8 Grey 9 ight Blue 10 Light Green 11 Light Cyan 12 Light Red 13 Light Magenta 14 Yellow 15 High intensity white Parameter The textcolor procedure s only parameter is an expression of integral type that specifies the new text foreground color Example J RRR KR KKK IK kkk k KR k k k k k k IK k k k K k k k kK k k k IR k k k IA I k k k k k k k k k k I k This program uses the built in procedure textcolor to set the screen foreground color program fc output W44 const black 0 blue 1
363. sor The type of the value returned by this function is always the same as the type of the parameter Parameter The succe function s only parameter is an expression of ordinal type Example succ false returns true succ 21 returns 22 succ A returns B assuming the ASCII or ANSI character set Portability Operating Systems Al1l Standard Pascal Yes 7 2 62 The supported function Description The supported function returns a value of type boolean which indicates whether a particular feature is supported on the current platform The parameter passed to this function identifies the feature to be tested for support If the feature is supported then the value true is returned and if the feature is not supported then the value false is returned Irie Pascal defines a constant for each feature whose availability can be checked with this function It is recommended that you use one of these predefined constants as seen in the example above to indicate which feature you want to check the availability of This makes your program easier to read and is probably easier than remembering which values corresponds to which features Parameter The supported function s only parameter is an expression of integral type and must be equal to one of the feature constants Example supported feature odbc returns trueif the current platform supports ODBC and falseotherwise Portability Operating Systems Al1l Standard Pascal
364. sstatic In the example above rs is the recordset object that will contain the opened recordset conn is the connection object containing an open connection to a database sSQL is a string variable containing the SQL statement that defines the recordset rsstatic specifies that a static recordset should be opened Portability Operating Systems Al1l Standard Pascal No 4 2 49 sql tc_all Description If the transsupport property of a connection type object is equal to this constant i e sql_te_all then the connection supports transactions which can contain DML data management and or DDL data definition statements Portability Operating Systems Al1l Standard Pascal No 4 2 50 sql _tc_ddl_ commit Description If the transsupport property of a connection type object is equal to this constant i e sql_te_ddl_commit then the connection supports transactions which can contain DML data management statements DDL data definition statements in the transactions cause them to be committed Portability Operating Systems Al1l Standard Pascal No 4 2 51 sql te ddl ignore Description If the transsupport property of a connection type object is equal to this constant i e sql_te_ddl_ignore then the connection supports transactions which can contain DML data management statements DDL data definition statements in the transactions are ignored Portability Operating Systems Al1l Standard Pascal No 4 2 52 sql
365. st Argument The first argument passed to the getsockname function is the socket whose name you want to get The Second Argument The second argument passed to the getsockname function is the operating system address of a buffer you have supplied to store the name of the socket You should use the built in function addr to get the operating system address of this buffer The Third Argument The third argument passed to the getsockname function is the length of the buffer you supplied to store the name of the socket After the getsockname function returns successfully this argument will contain the actual length of the name stored in the buffer Return Values The getsockname function returns a value of integer type that indicates whether the call was successful A value of zero means that the call succeeded A value of SOCKET_ERROR indicates that the called failed and in this case you can use the WSAGetLastError function to retrieve a code that identifies the error that caused the call to fail NOTE The constant SOCKET ERROR is declared in the system include file WinSock2 inc Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 16 4 The getsockopt function Description The getsockopt function retrieves the current value of a socket s option If an option has not been set with t
366. stems Al1 Standard Pascal No 4 2 57 usr_x Description usr_x can be AND d see and operator bitwise with the filemode retrieved by the built in procedure getfilemode to determine whether the owner of a file or directory folder has permission to execute the file or search the directory folder Example For example the simple program below asks for a filename and then displays the file permissions for the owner of the file program OwnerPermissions input output var s filename mode integer isdir boolean begin write readin s s fexpand s getfilemode s mode isdir mode and dir bit lt gt 0 if isdir then riteln s is a directory lse riteln s is not a directory rite Owner permissions f mode and usr r lt gt 0 then rite Read f mode and usr w lt gt 0 then rite Write f mode and usr x lt gt 0 then f isdir then rite Search lse rite Execute titeln end Enter filename S00 S PHP S eS PS S 0 Portability Operating Systems Al1l Standard Pascal No 4 2 58 writemode Description writemode is used with the built in procedure open to specify that the file variable should be opened in write only mode and with the built in procedure popen to specify that the pipe should be opened for writing Examples open file variable filename writemode open for writing
367. system address of the name This type is choosen because the format of a socket s name could depend on what address family the socket belongs to and using the address type leaves it up to you to choose the appropriate type Usually the socket will belong to the internet address family and you can use a variable of type sockaddr _in to specify the name sockaddr _in is a record type with the following four fields sin_family The address family usually AF INET sin_adadr The IP address sin_port The port number sin_zero Eight bytes of zeroes If you do not care what IP address is assigned to the socket then you should specify the constant INADDR_ANY for the sin_addr field This allows the underlying network service provider to choose an appropriate IP address If you do not care what port number is used then you should specify zero as the sin_port field This allows the underlying network service provider to choose an appropriate port number NOTE The constant IVADDR_ANY and the type sockaddr_in are declared in the system include file WinSockz2 inc The Third Argument The third argument passed to the bind function is the length in bytes of the name to be assigned to the socket Return Values The bind function returns a value of integer type that indicates whether the call was successful A value of zero means that the call succeeded A value of SOCKET_ERROR indicates that the called failed and in this case you can use the WSA
368. t 0 then ite Read mode and grp_w lt gt 0 then ite Write mode and grp_x lt gt 0 then isdir then te Search ee zz le MAh hh 0 e Execute te Other permissions mode and oth_r lt gt 0 then ite Read mode and oth_w lt gt 0 then ite Write mode and oth_x lt gt 0 then isdir then ite Search else write Execute writeln end Zep sr ere es PF ee ee a ET a a S i 4 2 62 1 The platform constants Irie Pascal supports several integer constants which can be compared with the value returned by the built in function platform to determine the platform your program is running on The platform constants are listed below e platform dos platform error e platform _fbsd platform linux platform os2 platform solaris platform solaris sparc platform _win32 4 2 63 1 The recordset type constants Irie Pascal supports several integer constants which are used when opening a recordset see recordset open to specify the type of recordset you want to open The recordset type constants are listed below rsdefault rsdynamic rsforward rskeyset rsstatic 4 3 1 Constant definitions Constant definitions are used to create constant identifiers i e identifiers that are associated with a constant Example const Space message First de last 10 DaysInYear 365 25 minint maxint linefeed 10 Hell
369. t is in the queue then this function will block and wait until a connection request is made before returning to the caller Non blocking mode enabled If the listening socket has it s non blocking mode enabled and no connection request is in the queue then this function will return JVVALID_SOCKET indicating failure If you then call the WSAGetLastError function to find out the reason for the failure the error code returned will be WSAEWOULDBLOCK NOTE The constants WSAEWOULDBLOCK and INVALID_SOCKET are declared in the system include file WinSock2 inc Declaration The system include file WinSock2 inc contains the following declaration for the accept function function accept s SOCKET addr address var addrlen integer SOCKET external dll ws2_32 d11 Arguments The First Argument The first argument passed to the accept function is the listening socket that you want to accept a connection request The Second Argument The second argument passed to the accept function can be used to retrieve the name of the socket whose connection request was accepted If you are interested in the name of the socket whose connection request was accepted then you should use the built in function addr to pass the operating system address of a variable into which the accept function should store the socket s name See the bind function for more information on socket names If you are not interested in the name of the socket whose connect
370. t that for local declarations the sub block declaration group must be last So if the relaxed declarations extension is enabled then the following program is valid program summing output const first 1 last 100 type num first last var io num type atype array first last of integer var a atype sum integer begin sum 0 for i begin sum sum i ali sum end for i last downto first do writeln i a il end first to last do even though it has two type definition groups type num first last and type atype array first last of integer and two variable declaration groups var i num and var a atype sum integer In Standard Pascal i e if the relaxed declarations extension is not enabled you would have to combine these groups so you would have the following program summing output const first 1 last 100 type num first last atype array first last of integer var io num a atype sum integer begin sum 0 for i first to last do begin sum sum i afi sum end for i last downto first do writeln i alil end 13 3 Allow constant ranges Standard Pascal requires that case constants be specified individually When the constant ranges extension is enabled you can use constant ranges to specify a number of consecutive case constants To use a constant range you specify the
371. t the file variable be opened in read write mode i e for both reading and writing The name of the file variable referenced by the first parmater controls which file is opened by the open procedure If the name is a non empty string then a file with that name is opened If the name is an empty string then the file opened is either the standard output file or a temporary file with a system generated name depending on the project options set when the program was compiled File variables can get named in the following ways e By calling the built in procedure assign e By supplying the second parameter when calling the built in procedures open append popen reset or rewrite By using the file variables as program parameters Example open f filename readmode this is the same as reset f filename open f filename writemode this is the same as rewrite f filename open f filename appendmode this is the same as append f filename The following call to open open f test txt readmode writemode will open the file test txt in read write mode i e for both reading and writing Portability Operating Systems Al1 Standard Pascal No 7 4 36 The opendir procedure Description The opendir procedure opens a directory variable i e associates the directory variable with a directory NOTE Directories are also called folders Parameters
372. tation dependent Irie Pascal evaluates index expressions of indexed variables from left to right For example given var x 1 10 1 20 of integer and later on x i J 20 i will get evaluated before j 17 4 Order of evaluation of expressions of a member designator 6 7 1 The order of evaluation of expressions of a member designator is implementation dependent Irie Pascal evaluates expressions of member designators from left to right For example given const low a high z var letter set of char and later on letter low high low will be evaluated before high 17 5 Order of evaluation of member designators 6 7 1 The order of evaluation of the member designators of a set constructor is implementation dependent Irie Pascal evaluates member designators of set constructors from left to right For example given var yes set of char and later on y will be evaluated before Y 17 6 Order of evaluation of operands of dyadic operators 6 7 2 1 The order of evaluation of the operands of a dyadic operator is implementation dependent In other words for operators with two operands left and right the order in which the operands are evaluated is implementation dependent The operands can be evaluation left to right right to left in parallel or they may not both be evaluated Irie Pascal always evaluates the operands of the following operators from left to right Addition Subtraction
373. ted 4 2 15 feature_opendir opendir supported 4 2 16 feature popen popen supported 4 2 17 feature_readdir readdir supported 4 2 18 feature_readkey readkey supported 4 2 19 feature_rewinddir rewinddir supported 4 2 20 feature_textbackground textbackground supported 4 2 21 feature_textcolor textcolor supported 4 2 22 feature _wherex wherex supported 4 2 23 feature_wherey wherey supported 4 2 24 grp r 4 2 25 grp w 4 2 26 grp x 4 2 27 maxbyte 4 2 28 maxchar 4 2 29 maxint 4 2 30 maxword 4 2 31 nil 4 2 32 oth r 4 2 33 oth w 4 2 34 oth x 4 2 35 platform dos 4 2 36 platform error 4 2 37 platform fbsd 4 2 38 platform linux 4 2 39 platform os2 4 2 40 platform solaris 4 2 41 platform solaris sparc 4 2 42 platform win32 4 2 43 readmode 4 2 44 rsdefault 4 2 45 rsdynamic 4 2 46 rsforward 4 2 47 rskeyset 4 2 48 rsstatic 4 2 49 sql tc all 4 2 50 sql tc ddl commit 4 2 51 sql tc ddl ignore 4 2 52 sql tc dml 4 2 53 sql tc none 4 2 54 true 4 2 55 usr r 4 2 56 usr w 4 2 57 usr X 4 2 58 writemode 4 2 59 Feature Constants 4 2 59 1 The feature constants 4 2 60 File Mode 4 2 60 1 The file mode constants 4 2 61 Permission Constants 4 2 61 1 The permission constants 4 2 62 Platform Constants 4 2 62 1 The platform constants 4 2 63 Recordset Type Constants 4 2 63 1 The recordset type constants 4 3 User Defined Constant Identifiers 4 3
374. ted as follows array m n o p of type is treated like array m of array n of array o of array p of type NOTE This is the opposite of the way dimensions are ordered by C language compilers address This is a 32 bit value which is an operating system address 1 e an address that is meaningful to external functions and procedures cstring These are null terminated sequences of characters the same format used by C programs to store strings pointer This is a 32 bit value which is a virtual address i e an offset from the beginning of the IVM Executable s Data segment Virtual address are probably meanless to external functions and procedures and therefore you should use the built in function addr to convert virtual addresses into operating system addresses before passing them to external functions or procedures record These are simply sequences of the fields The size of the gaps if any between fields is determined by the size of the fields and the current alignment setting string These are length prefixed sequences of characters Strings with maximum lengths less than or equal to 255 are prefixed by a byte containing the actual length of the string String with maximun lengths greater than or equal to 256 are prefixed by an integer containing the actual length of the string NOTE This representation is typical of the way strings are represented in Pascal programs but is very different from the way way stri
375. tegral types are one of the following types or subranges of one the following types address byte integer shortint shortword word NOTE In Standard Pascal the integral types are integer and subranges of integer 5 6 List types Description As an extension to Standard Pascal Irie Pascal supports list types List types define ordered collections of values of a single type called the list s component type Each value in a list type s collection is identified by it s position in the collection Unlike file types the values in a list type s collection are NOT persistent i e they are not stored when your program is not running The size of the collection of values defined by a list type i e the number of values in the collection is potentially unlimited List types do not impose any limit on the size of their collections In practice the maximum size of a list type s collection is determined by the amount of memory available to your program Example Here are some examples of list types list lis of integer of char Below is a simple example program that uses a list to store and sort random integer values program listexample output var l list of integer i integer procedure SortList var i temp integer swapped boolean begin writeln Sorting Bubble sort the list repeat swapped false for i 1 to length 1l 1 do begin if l i gt 1 i 1 t
376. tements either perform one of two actions or conditionally perform a single action If statements include the following e Anif condition which is specified by a boolean expression i e an expression of boolean type The if condition is evaluated and its value determines which action if any is performed If the value of the if condition is true then the action specified by the statement in the then part is performed If the value of the if condition is false and an else part is present then the action specified by the statement in the else part is performed If the value of the if condition is false and an else part is not present then the execution of the if statement is terminated A then part which contains a statement specifying an action to perform This statement can be a compound statement containing a statement sequence If this statement transfers program execution to a statement outside of the if statement then execution of the if statement is terminated when program execution is transfered e An optional else part which contains a statement specifying an action to perform This statement can be a compound statement containing a statement sequence If this statement transfers program execution to a statement outside of the if statement then execution of the if statement is terminated when program execution is transfered Example For example if x y then writeln x is equal to y is an if statement that conditionally
377. tes Character Literals Enclosed By Double Quotes Character literals can be formed by enclosing the character being represented in double quotes NOTE Double quote characters in character literals enclosed by double quotes are represented as a pair of double quote characters So A represents the character A and mum represents the character This second form of character literals is an extension to Standard Pascal and is provided mainly to make it easy to represent characters containing single quotes i e you can enclose character literals representing single quotes with double quotes without using double single quotes like instead of Character Literals prefixed By The Pound Sign Character literals can be formed by prefixing the ordinal value of the character being represented by the pound sign So 65represents the character with ordinal value 65 i e A and 9represents the character with ordinal value 9 i e the tab character Examples A rot J LES SS SE i THF A wo woo wor Won 65 43 32 39 34 Syntax character literal string element one string element two character code character cod digit sequenc digit sron rA 2 3 4 75 6 7 B 1 19 digit sequence digit digit printable character any character including a space that has a visual representation string element one printable character string e
378. tes a file variable with the pipe i e opens the file variable The popen procedure can open the file variable in read only mode write only mode or read write mode Read Only Mode If the file variable is opened in read only mode then the program can read the pipe and retrieve values written to the pipe by the process However the program can not write values through the pipe for the process to read Write Only Mode If the file variable is opened in write only mode then the program can write values to the pipe for the process to read However the program can not read the pipe to retrieve values written to the pipe by the process Read Write Mode If the file variable is opened in read write mode then the program can write values to the pipe for the process to read and read the pipe to retrieve values written to the pipe by the process Parameter 1 The first parameter is a reference to the file variable to be opened The second parameter is an expression of string type or char type and is the program from which the process is created 3 The third parameter is an expression of integral type which specifies the mode the file variable should be opened in The file mode constants can be used to specify the mode The readmode and writemode constants can be added or OR d together to specify that the file variable be opened in read write mode i e for both reading and writing Portability Operating Systems Al1l Stand
379. the current platform program ShowPlatform output begin case platform of platform dos writeln DOS platform _os2 writeln 0S 2 platform _win32 writeln Windows platform linux writeln Linux platform fbsd writeln FreeBSD platform solaris writeln Solaris x86 platform solaris sparc writeln Solaris Sparc platform error writeln Unknown Platform end end Portability Operating Systems Al1l Standard Pascal No 4 2 41 platform_solaris sparc Description platform_solaris_sparc can be compared with the value returned by the built in function platform to determine whether the current platform is Solaris Sparc i e the interpreter running your program is from the Solaris Sparc edition of Irie Pascal Example The following simple program displays the current platform program ShowPlatform output begin case platform of platform dos writeln DOS platform_os2 writeln 0S 2 platform win32 writeln Windows platform linux writeln Linux platform fbsd writeln FreeBSD platform solaris writeln Solaris x86 platform solaris sparc writeln Solaris Sparc platform error writeln Unknown Platform end end Portability Operating Systems Al1l Standard Pascal No 4 2 42 platform_win32 Description platform_win32 can be compared with the value returned by the built in func
380. the error code stored for the socket The system stores an error code for each socket which is different from the error code returned by the WSAGetLastError function which is stored for each thread Calling the getsockopt function to retrieve the error code stored for a socket causes the error code to be reset However a successful call to a WinSock2 library function does not reset the error code stored for each socket SO_LINGER This opton is of type linger and returns the current linger options for the socket see the closesocket function for more information about linger options SO MAX MSG SIZE This option is of integer type and is the maximum size of a datagram for datagram sockets SO_OOBINLINE This option is of type BOOL and indicates whether OOB data will be received in the normal data stream SO_TYPE This option is of integer type and is the kind of the socket e g SOCK_STREAM NOTE Socket options of type BOOL are retrieved into an integer and a value of zero means false and an non zero value means true The Fourth Argument The fourth argument passed to the getsockopt function is the operating system address of the buffer you have supplued to store the value of the socket option You should use the built in function addr to get the operating system address of this buffer For the SO_LINGER socket option the buffer should be a linger structure for the other options the buffer should be of integer type
381. the input file If you run this program and don t supply a program argument like ivm vowels then the program reads from the standad input file If you run this program with a program argument like ivm vowels filename then the program will open the file named filename and read from it program vowels f output var EF file of Ghari tot vow integer char begin reset f Open the input file in readmode tot 0 Initialize total number of chars read so far vow 0 Initialize total number of vowels read so far while not eof f do begin read f c Read character case c of tati rat rae toti ul AT E rit Ot U VOW vow 1 otherwise include otherwise so that non vowels don t cause errors end tot i tot 13 end writeln Total characters read tot writeln Vowels read vow end Portability Operating Systems All Standard Pascal Yes 7 4 49 The rewinddir procedure Description The rewinddir procedure rewinds a directory variable i e alters the directory variable in such a way that filenames read from the directory variable start with the name of the first file in the directory associated with the directory variable NOTE Directories are also called folders Parameter The rewind procedure s only parameter is a reference to a directory variable to rewind Portability Operating Systems Al1l Standard Pascal No
382. the least significant version number is zero Portability Operating Systems All Standard Pascal No 7 2 74 The wait function Description The wait function accepts one or more parameters as described below and waits i e suspends execution of the program until signalled to return or until a timeout period expires Parameters The first parameter is an expression of integral type which specifies the timeout period in milliseconds If the value of the first parameter is zero then the wait function doesn t actually wait instead it just checks whether it has been signaled to return If the value of the first argument is equal to the built in contant maxword then the timout interval is infinite and the wait function will wait indefinitely until signalled to return The other parameters if supplied are expressions of integral type which specify handles to synchronization objects The wait function will wait until one of the synchronization objects signals it to return or until the timeout interval expires The wait function returns the handle to the synchronization object that signaled it or zero if the timeout period expires before it was signalled to return This function was implemented to make it easy to write well behaved services i e services that stop running when requested to do so The stopserviceevent function returns a handle to a synchronization object that will signal when the program if it is a service is req
383. the parameter is a lowercase alphabetic character then the value true is returned and if the parameter is not a lowercase alphabetic character then the value false is returned Parameter The islower function s only parameter is an expression of char type Example islower a returns true islower A returns false islower 1 returns false islower returns false islower returns false Portability Operating Systems Al1l Standard Pascal No 7 2 31 The isnull function Description The isnull function returns a value of type boolean which indicates whether the parameter passed to it is null If the parameter is null then the value true is returned and if the parameter is not null then the value false is returned This function is usually used to test values retrieved from databases with recordset field Parameter The isnull function s only parameter is an expression of variant type Example The following code fragment uses isnull to check the values of the last_name and first_name fields to see if they are null and if so handle them specially new rs rs open conn select last name first name from customer rsforward while not rs eof begin if isnull rs field last_name then write NULL else write rs field last_name write if isnull rs field first name then writeln NULL else writeln rs field first name rs movenext end rs clos
384. then writeln ERROR else begin iRet lstrcpy addr strAddress AddrRet writeln strAddress end AddrAddr AddrAddr sizeof address Get the next element of the array AddrTemp DereferenceAddress AddrAddr end end writeln end end DisplayHostEntInfo Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 14 2 The gethostbyaddr function Description The gethostbyaddr function returns information about a host identified by address The host information is returned in a structure of type hostent This structure is allocated by the WinSock2 library and your program should not attempt to modify or de allocate the structure or any of it s components Only one copy of the hostent structure is allocated per calling thread and since Irie Pascal programs only have one thread there will be only one copy of this structure allocated for your program As a result you should copy any host information you need from the structure before calling any other Windows Sockets functions Declaration The system include file WinSock2 ine contains the following declaration for the hostent and p_hostent types and the gethostbyaddr function hostent packed record h_name address h_aliases address h_addrtype shortint h_length shortint h_add
385. tion 5which results in the integer value 8 5 0which results in the real value 8 0 Swhich results in the real value 8 0 5 0which results in the real value 8 0 8 4 2 3 Unary plus Description When the operator has only one operand of integral type or real type it performs unary plus which means that the result of the operation is the operand in other words unary plus does nothing 8 4 2 4 Subtraction Description When the operator has two operands of integral type or real type it performs subtraction according to the following rules First the numeric type conversion rules are applied After applying the numeric type conversion rules the operands are either both of integer type or both of word type or both of real type or both of address type or one operand is of address type and the other operand is not If both operands are of integer type then unsigned integer subtraction is performed and the result is a value of type integer If both operands are of word type then unsigned integer subtraction is performed and the result is a value of type word e If both operands are of real type then real i e floating point subtraction is performed and the result is a value of type real If both operands are of address type then unsigned integer subtraction is performed and the result is a value of type integer e If one operand is of address type and the other operand is not then unsi
386. tion Description The isalphanum function returns a value of type boolean which indicates whether the parameter passed to it is an alphanumeric character i e an alphabetic character or a digit If the parameter is an alphanumeric character then the value true is returned and if the parameter is not an alphanumeric character then the value false is returned Parameter The isalphanum function s only parameter is an expression of char type Example isalphanum a returns true isalphanum A returns true isalphanum 1 returns true isalphanum returns false isalphanum returns false Portability Operating Systems All Standard Pascal No 7 2 29 The isdigit function Description The isdigit function returns a value of type boolean which indicates whether the parameter passed to it is a digit If the parameter is a digit then the value true is returned and if the parameter is not a digit then the value false is returned Parameter The isdigit function s only parameter is an expression of char type Example isdigit a returns false isdigit A returns false isdigit l returns true isdigit returns false isdigit returns false Portability Operating Systems Al1l Standard Pascal No 7 2 30 The islower function Description The islower function returns a value of type boolean which indicates whether the parameter passed to it is a lowercase alphabetic character If
387. tion In other words it is an error to perform input from a file which is not open for reading i e the file is either not open or open for writing Error Handling This error is reported if I O checking is enabled 18 16 Input from undefined file Official Description 6 6 5 2 It is an error if the file is undefined immediately prior to any use of get or read Simplified Description In other words it is an error to perform input on a file which does not exist Error Handling This error is reported if I O checking is enabled 18 17 Reading past end of file Official Description 6 6 5 2 It is an error if end of file is true immediately prior to any use of get or read Simplified Description In other words it is an error to attempt to read past the end of a file Error Handling This error is reported if I O checking is enabled 18 18 Reading out of range values Official Description 6 6 5 2 For read it is an error if the value possessed by the buffer variable is not assignment compatible with the variable access Simplified Description In other words it is an error to read a value into a variable if the value is not assignment compatible with the variable Error Handling This error is reported if range checking is enabled 18 19 Writing out of range values Official Description 6 6 5 2 For write it is an error if the value possessed by the expression is not assignment compatible with the
388. tion The rawwrite procedure writes up to a specified number of characters from a character buffer to a file The actual number of characters written by this procedure may be less than the maximum number of characters specified if there is an I O error you can check this by disabling I O checking and using the getlasterror function Parameter The first parameter is a reference to the file variable associated with the file to write The second parameter is a reference to the character buffer used to store the characers to be written to the file The character buffer must be a variable of type string or a packed array of type char 3 The third parameter is an expression of integral type which specifies the maximum number of characters to be written to the file 4 The fourth parameter is a reference to a variable of type integer or type word which will contain the actual number of characters written to the file N Re Example The simple program below copies the contents of an input file into an output file It is similar to the UNIX program cat The program uses the built in procedures rawread and rawwrite to perform the T O program cat f g const max 400 var f g text buffer packed array 1 max of char actual integer begin reset f rewrite g while not eof f do begin rawread f buffer max actual if actual lt gt 0 then rawwrite g buffer actual actual end clos
389. tion carriage return characters do not appear when individual characters are read from text files This treatment of carriage return characters is intended to convert carriage return line feed pairs that are used as end of line markers in some text files into a single end of line character i e a line feed chr 10 15 1 Implementation limits Standard Pascal allows implementations to impose limits on the size of a program and its data Irie Pascal imposes various limits on the size and complexity of programs and their data that it will process These limits are listed below Length of source lines Number and nesting of statement sequences Nesting of functions procedures Range of variant selector s type amp Number of variants Size of integer constants Size of real constants Size of code and data Number of set elements Nesting of statements Nesting of include directives Stack size Number of Source Lines 15 2 Length of source lines The maximum length of a source line that the Irie Pascal compiler will process is 400 characters If you exceed this limit the compiler will issue an error message 15 3 Number and nesting of statement sequences Statement sequences are the statements that occur between begin and end and between repeat and until Statement sequences are nested when one statement sequence is contained in another The maximum number of statement sequences in a function or procedure is 2 147 486 64
390. tion platform to determine whether the current platform is 32 bit Windows i e your program is a Windows EXE executable or your program is a IVM executable running under the interpreter from the Windows edition of Irie Pascal Example The following simple program displays the current platform rogram ShowPlatform output egin ase platform of latform_ dos writeln DOS form _os2 writeln OS 2 form win32 writeln Windows form linux writeln Linux oc ee Cr Cr Cr at Lal at tform fbsd writeln FreeBSD tform solaris writeln Solaris x86 tform_ solaris sparc writeln Solaris Sparc tform error writeln Unknown Platform o D pT T S end Portability Operating Systems Al1l Standard Pascal No 4 2 43 readmode Description readmode is used with the built in procedure open to specify that the file variable should be opened in read only mode and with the built in procedure popen to specify that the pipe should be opened for reading Examples open file variable filename readmode open for reading open file variable filename readmodetwritemode open for reading and writing open file variable filename readmode or writemode open for reading and writing Portability Operating Systems Al1l Standard Pascal No 4 2 44 rsdefault Description rsdefault is used when opening a r
391. to z do if c in s then writeln c end 8 4 7 4 Set intersection Description When the operator has operands of set type then it performs set intersection i e the result of the operation is a set made up of the members common to both the left and right operands Example a piy tat tar raty Eeu Wa hy war results in tat Tot To see this try the example program below program seti output type letter a z var s set of letter c letter begin s i val Tb To vaT tat Ney Mah Yt for c a t to z do if c in s then writeln c end 8 4 7 5 Set inclusion in Description The in operator takes two operands the left operand is of ordinal type and the right operand is of set type The result of the operation is of boolean type and is true if the left operand is a member of the right operand and is false otherwise Example ra in of ta bt her returns true b an ha bt he returns true ne dm tan bt het returns true a im at th tet returns false tan in Itat Soh Neel returns false ta in returns false 8 4 8 1 The bitwise operators The bitwise operators are not bitwise and bitwise or bitwise xor bitwise e Bit shift left shl e Bit shift right shr 8 4 8 2 not bitwise Description As an extension to Standard Pascal Irie Pascal supports using the not operator with an operand of integral ty
392. to the socket The Windows Sockets API supports three commands and these commands are 1 FIONBIO Enables or disables the socket s non blocking mode The value of the third argument specifies whether non blocking mode is enabled or disabled Use a non zero value for the third argument to enable non blocking mode and zero to disable non blocking mode NOTE When a socket is created it s non blocking mode is disabled 2 FIONREAD Returns the amount of data that can be read from the socket in a single call This is not necessarily the same as the total amount of data waiting to be read from the socket For datagram sockets the value returned by this command is the size of the first datagram waiting to be read NOTE The value returned by this command is placed in the third argument to this function 3 SIOCATMARK Returns whether or not all Out Of Band OOB data has been read This command returns a non zero value if there is no OOB data waiting to be read and zero if there is OOB data waiting to be read A full description of OOB data is outside the scope of this manual however OOB data is basically data that is sent with high priority OOB data can jump the queue and be read at the other end before normal data that was sent previously NOTE OOB data and normal data are never read together in the same call NOTE The value returned by this command is placed in the third argument to this function NOTE The constants FFONBIO FIONREAD and SIO
393. tory t is NOT a direct then Dir filename tory then list it 5 15 11 integer type Description integer is the type identifier for a built in ordinal type whose values are 32 bit signed integers between 2147483647 and 2147483647 maxint Example Below is a simple example program that prints the odd numbers between and 24 program OddNumbers output const first last var i i 24 integer function IsOdd i begin IsOdd end integer i mod 2 lt gt 0 begin for i first to last do if IsOdd i then writeln i end boolean Portability Operating Systems Al1l Standard Pascal Yes 5 15 12 real type Description real is the type identifier for a built in type whose values are 64 bit real numbers Example For example the rather pointless program below uses the real type to repeatedly divide a number into thirds program thirds output const initial 37 6 lowest 0 05 var value real begin value initial repeat writeln value value 12 3 value value 3 until value lt lowest end Portability Operating Systems Al1l Standard Pascal Yes 5 15 13 registers type Description registers is the type identifier for a built in variant record type which is used to store the x86 processor registers before and after calls to the built in procedures intr and msdos The record layout is given below regtype byte
394. tory variable NOTE Directories are also called folders Parameters e The first parameter is a reference to the directory variable to read from The second parameter is a reference to the string variable that will store the filename read from the directory variable Example The simple program below opens the current directory and then uses readdir to read the names of all the files in the directory and then finally closes the directory when done program listdir output var ds ALE fn filename begin opendir d Open current directory repeat readdir d fn Get next file in directory if fn lt gt then writeln fn until fn closedir d Close directory end Portability Operating Systems Al1l Standard Pascal No 7 4 46 The readin procedure Description The readIn procedure reads values from the file associated with a file variable of type text into one or more variables and then skips to the beginning of the next line Parameters 1 The first parameter is optional and if supplied is a reference to the file variable associated with the file to read from If this parameter is not supplied then the readIn procedure reads values from the file associated with input 2 The other parameters are optional and if supplied are references to the variables used to store the values read from the file Reading From Text Files The readIn procedure always reads values from a text file i e
395. tter is executed Ifthe value is not a digit or a letter then the case statement completer is choosen and it s statement i e writelIn What is that is executed Irie Pascal implements case statements in two different ways depending on the type of the case index 1 Ifthe case index in the case statement has a type with 1024 values or less then Irie Pascal implements the case statement using a jump table 2 Ifthe case index in the case statement has a type with more than 1024 values then Irie Pascal implements the case statement as a series of hidden if statements In earlier versions of Irie Pascal the second if statement implementation had serious problems the rule that no two case list elements can have the same constant was not enforced and the case index was evaluated once for each case list element until a match was found As a result of these problems a warning message was issued when the second implementation was used These problems have now been removed from the second implementation so that now no matter what implementation is used the rule that no two case list elements can have the same constant is always enforced and the case index is never evaluated more than once As a result the warning message is no longer issued when the second implementation is used Syntax NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax case statement case case index case
396. tual parameters if present are passed to the formal parameters of the procedure If the procedure has no formal parameters then this step is skipped 2 Next program execution is transfered to the first statement in the procedure s block 3 Execution of the procedure statement is terminated when either the execution of the last statement in the procedure s block is terminated or when one of the statements in the procedure s block transfers program execution to a statement outside of the procedure s block Example writeln l 1 1 1 is a simple example When this procedure statement is executed the actual parameters 1 1 and 1 1 are passed to the procedure and then the procedure prints the actual parameters to the file associated with output Syntax NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax procedure statement procedure identifier actual parameter list read parameter list readln parameter list write parameter list writeln parameter list actual parameter expression variable access procedure identifier function identifier actual parameter list actual parameter actual parameter function identifier identifier procedure identifier identifier read parameter list file variable variable access variable access readin parameter
397. tural logarithm of the parameter passed to it The type of the value returned by this function is always real Parameter The In function s only parameter is a numeric expression i e an expression of integral type or of real type Example in 1 returns 0 0 in exp 1 returns 1 0 ln 100 returns 4 61 Portability Operating Systems Al1l Standard Pascal Yes 7 2 39 The log function Description The log function returns the logarithm to the base 10 of the parameter passed to it The type of the value returned by this function is always real Parameter The log function s only parameter is a numeric expression i e an expression of integral type or of real type Example log 1 returns 0 0 ln 10 returns 1 0 ln 100 returns 2 0 Portability Operating Systems Al1l Standard Pascal No 7 2 40 The locase function Description The locase function returns the lowercase letter corresponding to the parameter passed to it NOTE If there is no lowercase letter corresponding to the parameter passed to it then the parameter is returned unchanged The type of the value returned by this function is always char Parameter The locase function s only parameter is an expression of char type Example ocase a returns a ocase A returns a ocase H returns h ocase 1 returns 1 ocase returns ha ocase returns _ Portability Operating Systems Al1l Standard Pascal No
398. uaranteed not to identify any variable created using new Variables created by using the built in procedure new on pointer variables are called identified variables and are described in more detail in the next section Identified Variables Identified variables are created by calling the built in procedure new and passing a pointer variable as a parameter Identified variables are destroyed by calling the built in procedure dispose and passing as a parameter the same pointer variables that were used to create them You should destroy identified variables after you have finished using them Syntax The syntax for accessing an identified variable is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax identified variable pointer variable pointer variable pointer variable variable access where pointer variable is a reference to a pointer variable 6 10 Record variables Description Record variables are used to store values of record types i e collections of values of possibly different types Each member of a record type s collection is called a field and is usually identified by a name i e the field name Fields names have the same syntax as identifiers and no two fields in a record type can have the same name Every field in a record must have a name except for the variant selector of a variant record for which a name is optional A reference to a r
399. uating the expression The operations to be performed by an expression are specified using operators Example Here are some examples of expressions 3 5which results in the integer value 8 truewhich results in the boolean value true 3 5 0which results in the real value 8 0 14 2 3which results in the integer value 7 142 3which results in the integer value 9 Syntax NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax expression shift expression relational operator shift expression adding operator or or else xor factor sign unsigned constant sign variable access sign expression sign function method designator sign not factor set constructor Sign function designator multiplying operator div mod and and_then relational operator lt gt lt lt gt gt in shift expression simpl xpression shift operator simple expression shift operator shl shr sign simple expression term adding operator term term factor multiplying operator factor 8 2 Set constructors Description Set constructors are used in expressions to create values of set types and contain comma delimited lists of zero or more member designators Member designators specify set elements which are present and contain a single ordinal expression or
400. ude file WinSock2 inc Reference Information The authoritative source of information about the WinSock2 library is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com 12 6 2 Creating listening sockets Listening Sockets Listening sockets are sockets that you can use to isten for attempts by other sockets to establish a connection Usually listening sockets are created by server socket programs that need to know when client socket programs want to connect In order to create listening socket you need to do three things 1 Create a data socket see creating a data socket 2 Bind the socket to a local address see the bind function 3 Convert the data socket into a listening socket see the listen function 12 7 1 The bind function Description The bind function assigns a local name to a socket Declaration The system include file WinSock2 ine contains the following declaration for the bind function function bind s SOCKET name address namelen integer integer external dll ws2_32 d11 Arguments The First Argument The first argument passed to the bind function is the unnamed socket to which you want to assign a name The Second Argument The second argument passed to the bind function is the name to be assigned to the socket The type of this argument is address which means that you must use the built in function addr to pass the operating
401. ues are sequences of lines A line is a sequence of characters and every line in a text file is terminated by an end of line character except possibly the last line see Termination of all lines in text files Example The simple program below writes a short message to a text file program message fOut const OutputFileName message txt var fOut text begin rewrite fOut OutputFileName writeln fOut This file is generated by a very simple program writeln fOut which was written to help explain the text file type close fOut end Portability Operating Systems Al1 Standard Pascal Yes 5 15 19 word type Description word is the type identifier for a built in ordinal type whose values are 32 bit unsigned integers between 0 and 4294967295 maxword Example Below is a simple example program that prints the odd numbers between 1 and 24 program OddNumbers output const first last 2 var w word li 4 function IsOdd w word boolean begin IsOdd w mod 2 lt gt 0 end begin for w first to last do if IsOdd w then writeln w end Portability Operating Systems Al1l Standard Pascal No 5 15 20 1 The connection type Description connection is the type identifier for a built in object type whose values identify instances of connection objects As the name suggests instances of connection objects are used to connect to databa
402. uested to stop running The authoritative source of information about synchronization objects is the Microsoft Developers Network MSDN You can access the MSDN on the Microsoft website at msdn microsoft com Example For example the following procedure was taken from the WinServS sample program and uses the wait function to stop running when requested to do so ProgramState is a global variable used as a flag to signal when the program is stopping 1 e being shut down to prevent recursive calls to the ServerShutDown procedure The ServerShutDown procedure shuts down the program procedure CheckForStopServiceEvent const WAIT INTERVAL 0 begin if ProgramState lt gt Stopping and StopServiceEvent lt gt 0 then begin LogMessage Calling wait if wait WAIT INTERVAL StopServiceEvent StopServiceEvent then begin ProgramState Stopping ServerShutDown end end end Portability Operating Systems Al1l Standard Pascal No 7 2 75 The wherex function Description The wherex function returns the text mode screen s current x coordinate i e the column where the next character written to the screen will be displayed NOTE Screen columns are numbered from one not zero Parameter None Portability Operating Systems Windows and DOS Standard Pascal No 7 2 76 The wherey function Description The wherey function returns the text mode screen s current y coordinate i
403. uffer variable associated with the file variable will either be equal to the first value in the file or be undefined if the file is empty As the file is read the contents of the buffer variable will always either be equal to the next value to be read from the file or be undefined if there is no next value to be read from the file i e the entire file has been read Standard Pascal allows an implementation to delay the point at which the next value to be read from the file is actually transferred into the buffer variable until the buffer variable is referenced by the program This process is a part of what is called lazy I O where file output operations take place as soon as possible but file input operations are delayed Lazy I O is convenient for interactive programs where it is important that output operations displaying messages prompting the user to input values take place before input operations that actually try to read values from the user so that the user knows what he she is expected to type in Irie Pascal implements lazy I O When a file variable is opened in write only mode the contents of the buffer variable associated with the file variable is initially undefined You can write values to the file associated with the file variable by assigning values to the buffer variable associated with the file variable and using the built in procedure put to write the contents of the buffer variable to the file Irie Pascal allows file var
404. unction identifier formal parameter list result type Function identification function function identifier function identifier identifier H unction method designator object variable function method identifier actual arameter list goj function method identifier identifier function parameter specification function heading goto statement goto label hex digit digit a b e d e f hex digit sequence hex digit hex digit hexadecimal integer hex digit sequence identified variable pointer variable pointer variable identifier letter letter digit identifier list identifier identifier if statement if boolean expression then statement else part index expression expression index type ordinal type index type list index type index type indexed variable indexed variable array indexed variable string indexed variable array array variable index expression index expression indexed variable string string variable integral expression initial value ordinal expression integer number decimal integer hexadecimal integer binary integer integral constant constant integral expression expression label digit sequence identifier label declaration group label label label letter a b c d e g h i 3Z Se Pe an
405. untyped file types do not have component types there are no buffer variables associated with untyped file types Example For example below is a silly little program that illustrates how to use binary file types program silly var f binary begin rewrite f silly dat write f 100 67 56 false end Portability Operating Systems A1l1 Standard Pascal No 5 15 4 boolean type Description boolean is the type identifier for a built in enumerated type with two values false and true defined as below boolean false true The ordinal value of false is zero and the ordinal value of true is one The conditional statement o if and the looping statements while repeat use expressions of boolean type The operators and and_then not or or_else operate on expressions of boolean type Example For example below is a simple program that illustrates using the built in type boolean program Teenager input output var age integer teenager boolean begin write How old are you readin age teenager age gt 13 and age lt 19 if teenager then writeln Congratulations You are a teenager else writeln Sorry You are not a teenager end Portability Operating Systems Al1 Standard Pascal Yes 5 15 5 byte type Description byte is the type identifier for a built in 8 bit ordinal type whose values are the integers between 0 and 25
406. upported feature mysql then begin sUser GetStringValue Enter user id sPassword GetStringValue Enter password s MYSQL user sUsert password sPassword socket tmp mysql sock end else DisplayError No database support detected GetConnectionString s end begin new conn conn open GetConnectionString Add code here to process database Ir conn close dispose conn end Portability Operating Systems Al1l Standard Pascal No 4 2 15 feature_opendir opendir supported Description feature_opendir can be used to determine if the current platform supports the built in procedure opendir Example if supported feature closedir and supported feature readdir and supported feature opendir then begin open directory retrieve filenames and then close directory end else begin Opening reading and closing directories is not supported so do something else of abort end Portability Operating Systems Al1l Standard Pascal No 4 2 16 feature _popen popen supported Description feature_popen can be used to determine if the current platform supports calling the built in procedure popen Example if not supported feature popen then begin writeln popen not supported on the current platform abort end Portability Operating Systems All Standard Pascal No 4 2 17 feature_readdir readdir supported De
407. ur program should not attempt to modify or de allocate the structure or any of it s components Only one copy of the hostent structure is allocated per calling thread and since Irie Pascal programs only have one thread there will be only one copy of this structure allocated for your program As a result you should copy any host information you need from the structure before calling any other Windows Sockets functions Declaration The system include file WinSock2 ine contains the following declaration for the hostent and p_hostent types and the gethostbyname function hostent packed record h_name address h_aliases address h_addrtype shortint h_length shortint h_addr_ list address end p_hostent hostent function gethostbyname name address p_hostent external dll ws2_32 d11 Arguments The First Argument The first and only argument passed to the gethostbyname function is the operating system address of the buffer containing the name of the host you want to get information about The type of this argument is the built in type address so you must use the built in function addr to get the operating system address of the buffer The host name contained in the buffer must be a null terminated string i e a cstring The buffer pointed to by this argument must contain a valid host name and not an address If you have the address as a null terminated string of a host instead of the name of the host
408. value 1 is written as seven spaces and a 1 16 12 Default value of TotalWidth for real type 6 9 3 1 The default value of TotalWidth for real type is implementation defined In other words when writing real values to text files the default width of the output field is implementation defined Irie Pascal uses 9 as the default value of TotalWidth for real type 16 13 Default value of TotalWidth for boolean type 6 9 3 1 The default value of TotalWidth for boolean type is implementation defined In other words when writing boolean values to text files the default width of the output field is implementation defined Irie Pascal uses 8 as the default value of TotalWidth for boolean type 16 14 Number of digits written in exponents 6 9 3 4 1 ExpDigits is an implementation defined value representing the number of digit characters written in an exponent The value of ExpDigits is three 3 for the Windows edition of Irie Pascal and two 2 for the other editions So for example write one 1 0 will write one 1 0E 000 or one 1 0E 00 depending on the edition of Irie Pascal being used 16 15 Use of e or E as exponent character on output 6 9 3 4 1 The value of the exponent character e or E used on output of values of real type is implementation defined Irie Pascal uses E on output of values of real type 16 16 Case of characters used on output of boolean values 6 9 3 5 The case of each ch
409. wap function is designed to swap four byte i e 32 bit integral values If you pass two byte 1 e 16 bit or one byte i e 8 bit integral values they are converted to four byte integral values before the swap is performed As a result of this conversion the result of the swap might not be what you would expect See the examples below for more information Example For example assuming 32 bit little endian integers then 256 is stored in four bytes as follows 0010 So swap 256 results in the following integer 010 0 which is equal to 65536 As mentioned in the Notes above swapping two byte or one byte values might not give you the results you expect So what do you do if you have two byte values that you want to swap well consider the following program program example output var x shortint begin X 1234 x swap x writeln hex x end This program does not produce the output that you might expect i e 3412 This is because the swap function will convert its parameter into an four byte integer producing the following bytes 00 00 12 34 and then swap around these bytes producing 34 12 00 00 Actually a run time error vaue out of range will be issued because the value returned by the swap function i e 34120000 is too large to fit in a variable of type shortint As you can see the value you probably want is stored in the upper 16 bits of the result while the lower 16 bits contain zero The so
410. which results in the real value 15 0 0 5 0which results in the real value 15 0 3 5Swhich results in the integer value 15 3 Swhich results in the integer value 15 3 5which results in the integer value 15 w w ww 8 4 2 7 Real division Description When the operator has two operands of integral type or real type it performs real division and the result is a value of real type Any operands of integral type are converted into operands of real type before the division is performed Example Here are some examples using the operator to perform division 5 2which results in the real value 2 5 5 0 2 0which results in the real value 2 5 5 2which results in the real value 2 5 5 0 2 0which results in the real value 2 5 5 0 2 0which results in the real value 2 5 8 4 2 8 Integer division div Description The div operator takes two operands of integral type performs integral division and the result is a value of integral type Example Here are some examples using the div operator to perform division 5 div 2which results in the real value 2 5 div 2which results in the real value 2 5 div 2which results in the real value 2 5 div 2which results in the real value 2 8 4 2 9 Modulus mod Description The mod operator takes two operands of integral type and calculates the modulus The result of this operation is of integral t
411. y reference to the C function or procedure 3 A special case of passing arrays is passing C strings arrays of null terminated chars In this case you may want to pass a cstring by reference 4 Incases where the pointer is pointing to a variable whose type is not fixed or a null value can be passed or the pointer is pointing to a variable whose size is not fixed then you may want to pass the operating system address of the variable directly When you want to call a C function that expects a pointer parameter it is up to you to determine perhaps by reading a description of the function which one of the four scenarios just described in being used The sample program winhello pas is an example of how to call a function in a Windows DLL NOTE This program uses the winuser ine include file distributed with Irie Pascal to gain access to a pre written declaration for the Windows API function MessageBox 8 1 What are expressions Description Expressions specify that zero or more operations are to be performed on a group of operands also known as factors in such a way as to result in a single value of a particular type If the number of operations specified by an expression is zero then the expression must consist of a single operand and the value of the expression is the value of the operand The process of obtaining the value of an expression by obtaining the values of it s operands and performing any specified operations is called eval
412. y the sequence in which they are defined and they have consecutive ordinal numbers starting at zero The built in function ord can be used to retrieve the ordinal number of an enumerated constant Example Here are some examples of enumerated types red blue green low medium high married divorced widowed single In the examples above the first enumerated constant in each type i e red low and married have ordinal values of zero The second enumerated constant in each type i e blue medium and divorced have ordinal values of one The third enumerated constant in each type have ordinal values of two And the fourth enumerated constant in the last type has ordinal value 3 Syntax The syntax for enumerated types is given below NOTE for clarity some parts of the syntax are omitted see Irie Pascal Grammar for the full syntax numerated typ enumerated constant list enumerated constant identifier enumerated constant list enumerated constant enumerated constant 5 4 File types Description File types define collections of values that usually have the same type called the file type s component type File type component types can not be file types or types which contain file types There is a special file type named binary which has no component type and can define collections of values with different types The collection of values defined by a file type is usually just called a f
413. y types define collections of values of the same type called the array s component type and associates an index type with each collections Each member of an array s collection is called an array element and is identified by a value of the array s index type The number of array elements in an array is fixed and is equal to the number of values defined by the array s index type You can have arrays of arrays i e an array s component type may itself be an array type It is sometimes easier to think about arrays of arrays as multi dimensional arrays i e arrays defining a collection of values with an axis for each array component where each element is identified by values from each component array s index type Irie Pascal supports fixed length strings as defined in Standard Pascal i e fixed length strings which are simply packed arrays of char having a lower bound of one and an upper bound of two or greater Fixed length strings have special properties in addition to the properties they share with other arrays Fixed length strings unlike other arrays can be compared with the relational operators Also fixed length strings unlike other arrays can be read from and written to text files as a unit using the built in procedures read readln write and writeln NOTE Irie Pascal also supports variable length string types NOTE As a shorthand notation a multi dimensional array type can be defined by listing the index types of each of the c
414. ype The modulus operation is defined by Standard Pascal ISO IEC 7185 as follows A term of the form i mod j shall be an error if j is zero or negative otherwise the value of i mod j shall be that value of i k j for integral k such that 0 lt i mod j lt j Irie Pascal implements the mod operator according to the definition given above What does the definition really mean Well in the simple case where the operands are positive then the result of the operation is the remainder left over after dividing the left operand by the right operand This is the most common use of the mod operator but you should be aware that this does not hold when the left operand is negative You should also be aware that the right operand can not be negative Example For example if you run the program below program mods output var i 3 S38 3F J 1s 35 begin for i 3 to 3 do for j 1 to 3 do writeln i 1 mod j 1 i mod ji 1 end you will get the following output 3 mod 1 3 mod 2 3 mod 3 2 mod 1 l N 3 O Q N ll NFPORGCDOCOFO WWWNHNNFREFR EF OO 3 O Q N ll l OHO M O G e HO O O 8 4 3 1 The equality operators The equality operators are Is equal Is not equal lt gt 8 4 3 2 Is equal Description The operator takes two operands and compares them for equality If the operands are numeric then the numeric type conversion rules are applied before the
415. ype registers type regtype e shortint type shortword type single type word type 13 14 Enable non standard variables When the enable non standard variables extension is enabled Irie Pascal supports the use of the following non standard variables errors exitcode null 13 15 Enable non standard functions When the enable non standard functions extension is enabled Irie Pascal supports the use of the following non standard functions The addr function The concat function The copy function The copyword function The cosh function The countwords function The createobject function The dirsep function The fexpand function The filematch function The filepos function The filesize function The frac function The getenv function The getlasterror function The hex function The int function The ioresult function The isalpha function The isalphanum function The isdigit function The islower function The isnull function The isprint function The isspace function The isupper function The isxdigit function The keypressed function The length function The log function The locase function The lowercase function The paramcount function The paramstr function The pi function The platform function The pos function The ptr function The random function The readkey function The reverse function The sinh function The sizeof function The stopserverviceevent functio

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