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Intel® Fortran Compiler for Linux* Systems User's Guide, Volume I

1. The Fortran code to call this routine using the module CPROC Fortran 95 90 Module including procedure USE CPROC CALL PYTHAGORAS 3 0 4 0 X TYPE X END Calling C Procedures from an Intel Fortran Program Naming Conventions By default the Fortran compiler converts function and subprogram names to upper case The C compiler never performs case conversion A C procedure called from a Fortran program must therefore be named using the appropriate case For example consider the following calls 214 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications CALL PROCNAME The C procedure must be named PROCNAME X FNNAME II The C procedure must be named FNNAME In the first call any value returned by PROCNAME is ignored In the second call to a function FNNAME must return a value Passing Arguments Between Fortran and C Procedures By default Fortran subprograms pass arguments by reference that is they pass a pointer to each actual argument rather than the value of the argument C programs however pass arguments by value Consider the following e When a Fortran program calls a C function the C function s formal arguments must be declared as pointers to the appropriate data type e When aC program calls a Fortran subprogram each actual argument must be specified explicitly as
2. idb list 5 9 5 USE MODFILE 6 INTEGER 4 J 7 CHARACTER 1 CHR 8 J 2 8 idb print MODFILE J 256 Common Block Variables You can display the values of variables in a Fortran common block by using debugger commands such as print OF whatis To display the entire common block use the common block name To display a specific variable in a common block use the variable name For example idb list 1 11 1 PROGRAM EXAMPLE 2 98 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications 3 NTEGER 4 INT4 4 CHARACTER 1 CHR 5 COMMON COM_STRA INT4 CHR 6 7 CHR L 8 9 END idb print COM_STRA COMMON INT4 0 CHR HN idb idb print CHR TT If the name of a data item in a common block has the same name as the common block itself the data item is accessed Derived Type Variables Variables in a Fortran 95 90 derived type TYPE statement are represented in idb commands such as print Or whatis using Fortran 95 90 syntax form For derived type structures use the derived type variable name a percent sign and the member name For example idb list 3 11 3 TYPE X 4 INTEGER A 5 D END TYPE X 6 7 TYPE X Z 8 9 Z2 A 1 10 11 PRINT Z A idb print Z A 1 J 2 3 4 5 idb To display the entire object use the print command with the object name For example idb print 3 99 Intel Fortr
3. SSE2 Automatic vectorizer Parallelism in your code achieved automatically Parallelization Automatic generation of multithreaded code for loops Shared memory parallel programming with OpenMP Floating point optimizations Improved floating point performance Data prefetching Improved performance due to the accelerated data delivery Interprocedural optimizations Better performance for larger applications Whole program optimization Improved performance between modules in larger applications Profile guided optimization Improved performance based on profiling the frequently used procedures Processor dispatch Use of the latest Intel architecture features while maintaining object code compatibility with previous generations of Intel Pentium processors Compilation Phases The compiler processes Fortran language source and generates object files You decide the input and output by setting options when you run the compiler When invoked the compiler determines which compilation phases to perform based on the extension of the source filename and on the compilation options specified in the command line Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications The compilation phases and the software that controls each phase are shown below complaten EE IA 32 or Itanium based applications phase software Preprocess EH FPP ak Compile fortc
4. Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Read the input array from the data file OPEN UNIT 8 FILE datafile dat STATUS OLD READ 8 END 5 N INARR I I 1 N 5 CLOSE UNIT 8 Square all nonzero elements and store in OUTARR K 0 DO T I N F INARR I NE 0 THEN K K 4 1 add this line OUTARR K INARR I 2 ENDIF END DO Print the squared output values Then stop PRINT 20 N 20 FORMAT Total number of elements read is 14 PRINT 30 K O FORMAT Number of nonzero elements is I14 DO I 1 K PRINT 40 I OUTARR K 40 FORMAT Element I4 Has value I16 END DO END PROGRAM SQUARES The program SQUARES performs the following functions 1 Reads a sequence of integer numbers from a data file and saves these numbers in the array INARR The file datafile dat contains one record with the integer values 4 3 2 5 and 2 The first number indicates the number of data items that follow 2 Enters a loop in which it copies the square of each nonzero integer into another array OUTARR 3 Prints the number of nonzero elements in the original sequence and the square of each such element Note This example assumes that the program was executed without array bounds checking set by the check bounds command line option When executed
5. 242 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building FOR IOS_CAOVEEXI Specified file xxx already exists when OPEN statement specified STATUS NEW create new file using I O unit x Make sure correct file name directory path unit and so forth were specified in the source program Decide whether to e Rename or remove the existing file before rerunning the program e Modify the source file to specify different file specification I O unit or OPEN statement STATUS 1 11info 11 Unit not connected FOR IOS_UNINOTCON The specified unit was not open at the time of the attempted I O operation Check if correct unit number was specified If appropriate use an OPEN statement to explicitly open the file connect the file to the unit number 17 severe 17 Syntax error in NAMELIST input FOR IOS_SYNERRNAM The syntax of input to a namelist directed READ statement was incorrect 18severe 18 Too many values for NAMELIST variable FOR IOS_TOOMANVAL An attempt was made to assign too many values to a variable during a namelist READ statement 19 severe 19 Invalid reference to variable in NAMELIST input FOR IOS_INVREFVAR One of the following conditions occurred e The variable was not a member of the namelist group e An attempt was made to subscript a scalar variable e A subscript of the array variable was out of bounds e An array variable was specified wi
6. IDEC prefix eege eet 36 IMS Drei 36 DEC EEN 36 DIR EN 36 Heil 237 238 opt intel_fc_80 include fordef for file Eeer 119 __ELF__ preprocessor symbol 25 __gnu_linux__ preprocessor symbol Ferien 25 __ 1386 preprocessor symbol 25 __i386__ preprocessor symbol 25 __ia64 preprocessor symbol 25 __ia64__ preprocessor symbol 25 __INTEL_COMPILER preprocessor BVI DON sicnciccistnentnetdaptanaieicdanscenaaets 25 __linux preprocessor symbol 25 __linux__ preprocessor symbol 25 __unix preprocessor symbol 25 _FTN_ALLOC library routine 32 _OPENMP preprocessor symbol 25 1 1 compiler option 38 132 compiler option 60 6 66 compiler option 60 7 72 compiler option 60 8 80 compiler option 60 A absolute pathmame 10 ACCEPT statement 138 139 147 158 accessing data in mixed language programming E E N A A 191 accessing fileS eeee 147 ACTION specifier in OPEN Statement 160 address 261 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications of a common block passing 194 adjusting calling conventions mixed language programming 182 adjusting naming conventions mixed language programming OVEIVICW cccccceeeeeeeeeeeeees 186 ADVANCE specifier in READ statement 161 in WRITE statement 161 advancing BEEN 161 ALIAS poropertv 183 189
7. The limits and underflow characteristics for REAL 16 apply to the two separate real and imaginary parts of a COMPLEX 16 number Like REAL 16 numbers the sign bit representation is 0 zero for positive numbers and 1 for negative numbers File tordet for and its Usage The parameter file opt intel_fc_80 include fordef for contains symbols and INTEGER 4 values corresponding to the classes of floating point representations Some of these classes are exceptional ones such as bit patterns that represent positive denormalized numbers 117 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications With this file of symbols and with the FP_CLASS intrinsic function you have the flexibility of identifying exceptional numbers so that for example you can replace positive and negative denormalized numbers with true zero The following is a simple example of identifying floating point bit representations include fordef for real 4 a integer 4 class_of_bits a 57 0 Bit pattern is a finite number class_of_bits fp_class a if class_of_bits eg for_k_fp_pos_norm Or amp class_of_bits eq for_k_fp_neg_norm then print a iS a non zero and non exceptional value else print a is zero or an exceptional value end if end In this example the symbol for_k_fp_pos_norm in the file opt intel_fc_80 include fordef for plus the REAL 4 value 57 0 to the FP_CLASS intrins
8. 123 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications one two four or eight bytes and big endian CRAY proprietary floating point format for REAL and COMPLEX single and double precision numbers FDX Native little endian integers of the appropriate INTEGER size one two four or eight bytes and the following little endian proprietary floating point formats e VAX F_float for REAL KIND 4 and COMPLEX KIND 4 e VAX D_float for REAL KIND 8 and COMPLEX KIND 8 e IEEE style X_float for REAL KIND 16 and COMPLEX KIND 16 FGX Native little endian integers of the appropriate INTEGER size one two four or eight bytes and the following little endian proprietary floating point formats e VAX F_float for REAL KIND 4 and COMPLEX KIND 4 e VAX G_float for REAL KIND 8 and COMPLEX KIND 8 e IEEE style X_float for REAL KIND 16 and COMPLEX KIND 16 IBM Big endian integer data of the appropriate INTEGER size one two or four bytes and big endian IBM proprietary System 370 and similar floating point format for REAL and COMPLEX single and double precision numbers LITTLE_ENDIAN Native little endian integers of the appropriate INTEGER size one two four or eight bytes and the following native little endian IEEE floating point formats e S _float for REAL KIND 4 and COMPLEX KIND 4 e T_float for REAL KIND 8 and COMPLEX KIND 8 e
9. 38 OPEN reelle DEE 147 OPEN statement and file sharing 000 160 DEFAULTFILE specifier 149 FILE specifier ccceeee 149 for preconnected files 151 FORM specifier 139 147 ORGANIZATION specifier 142 POSITION specifier 160 RECL specifier 146 147 SPECIE S ccceeeeeeeeeeeeeeeeeeees 152 STATUS specifier 00 143 supplying a file name 147 USEROPEN specifier 164 OPEN statement 00 138 147 Index OPEN statement CONVERT method eeh 133 opening fileen ab ane 158 TNS eebe 152 opening files e 152 openmp compiler option 60 openmp_report compiler option 42 openmp_stubs compiler option 60 operators GENEE 106 opt intel_fc_80 bin directory 13 opt intel_fc_80 bin ifortvars csh file14 opt intel_fc_80 bin ifortvars sh file 14 opt_report compiler option 71 opt_report_file compiler option 71 opt_report_help compiler option 71 opt_report_level compiler option 71 opt_report_phase compiler option 71 opt_report_routine compiler option Sha ited sie cata atten cinta 71 optimization optons 71 OPTIONS statement 35 OPTIONS statement method 134 283 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications ORGANIZATION specifier in OPEN statemert
10. Commands to Create a Sample Program 26 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications During the early stages of program development the sample program files shown above might be compiled separately and then linked together using the following commands ifort c array_calc f90 ifort c calc_aver f90 ifort c main Eau ifort o calc main o array_calc o calc_aver o In this sequence of commands e The c option prevents linking and retains the o files e The first command creates the files array_calculator mod and array_calc o the name in the MODULE statement determines the name of module file array_calculator mod Module files are written into the current working directory e The second command creates the file calc_aver o e The third command creates the file main o and uses tOhe module file array_calculator mod e The last command links all object files into the executable program named calc To link files use the ifort command instead of the 1a command The order in which the file names are specified is significant This ifort command e Compiles the file array_calc 90 which contains the module definition and creates its object file and the file array_calculator mod e Compiles the file calc_aver 90 which contains the external function CALC_AVERAGE e Compiles the file main 90 main program The USE statement references the module file array_calculator mod
11. Really REAL 4 x y z 6 REAL 8 ydbl COMMON Really x y z 6 ydbl You can access this data structure from your C code with the following external data structure pragma pack 2 extern struct float x y z 6 double ydbl Really pragma pack You can also access C structures from Fortran by creating common blocks that correspond to those structures This is the reverse case from that just described However the implementation is the same because after common blocks and structures have been defined and given a common address name and assuming the alignment in memory has been dealt with both languages share the same memory locations for the variables Passing the Address of a Common Block To pass the address of a common block simply pass the address of the first variable in the block that is pass the first variable by reference The receiving C or C module should expect to receive a structure by reference In the following example the C function initcb receives the address of a common block with the first variable named n which it considers to be a pointer to a structure with three fields Fortran source code INTERFACE SUBROUTINE initcb BLOCK DECS ATTRIBUTES C initcb DECS ATTRIBUTES REFERENCE BLOCK INTEGER BLOCK END SUBROUTINE END INTERFACE INTEGER n REAL 8 x y COMMON CBLOCK
12. 105 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications example if program execution is suspended in a subprogram in Fortran the current language is Fortran If the debugger stops the program in a C function the current language becomes C The debugger uses the current language to determine the valid expression syntax and the semantics used to evaluate an expression The debugger sets the lang environment variable to the language of the current subprogram or code segment By manually setting the lang environment variable you can force the debugger to interpret expressions used in commands by the rules and semantics of a particular language For example you can check the current setting of 1ang and change it as follows idb print lang c idb set lang Fortran When the lang environment variable is set to Fortran names are case insensitive To make names case sensitive when the program was compiled with the names as_is option specify another language for the lang environment variable such as C view the variable then set the lang environment variable to Fortran Debugging a Program that Generates a Signal If your program encounters a signal exception at run time to make it easier to debug the program you should recompile and relink with the following command line options before debugging the cause of the signal e Use the fpen option to control the handl
13. FOR IOS_FLOINVEXC The total number of floating point invalid data traps encountered during program execution was nn This message appears at program completion 298 info 298 nnfloating overflow traps FOR IOS_FLOOVFEXC The total number of floating point overflow traps encountered during program execution was nn This message appears at program completion 299 info 299 nnfloating divide by zero traps 258 FOR IOS_FLODIVOEXC The total number of floating point divide by zero traps encountered during program Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications execution was nn This message appears at program completion 300 info 300 nnfloating underflow traps FOR IOS_FLOUNDEXC The total number of floating point underflow traps encountered during program execution was nn This message appears at program completion Footnotes 1 Identifies errors not returned by IOSTAT 2 The ERR transfer is taken after completion of the I O statement for error numbers 59 61 63 64 and 68 The resulting file status and record position are the same as if no error had occurred However other I O errors take the ERR transfer as soon as the error is detected so file status and record position are undefined 3 For errors 61 and 63 the severity depends on the check options used during compilation 4 Identifies errors that can be returned by STAT in an ALLOCATE statement 259
14. Specifying t raceback will increase the size of the executable program but has no impact on run time execution speeds The t raceback option functions independently of the debug option 86 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Debugging Using idb Debugging Using idb Overview See these topics Getting Started with Debugging Preparing Your Program for Debugging Using Debugger Commands and Setting Breakpoints Summary of Debugger Commands Debugging the SQUARES Example Program Displaying Variables Expressions in Debugger Commands Debugging Mixed Language Programs Debugging a Program that Generates a Signal Locating Unaligned Data Getting Started with Debugging The Intel Debugger idb is a source level symbolic debugger that lets you e Control the execution of individual source lines in a program e Set stops breakpoints at specific source lines or under various conditions e Change the value of variables in your program e Refer to program locations by their symbolic names using the debugger s knowledge of the Intel Fortran language to determine the proper scoping rules and how the values should be evaluated and displayed e Print the values of variables and set a tracepoint trace to notify you when the value of a variable changes Another term for a tracepoint is a watchpoint e Perform other functions such as examining core files exami
15. 00 71 traceback compiler option 86 traceback information ODI D 227 traceback miormaion 89 TRACEBACKQQ routine 227 EE 237 290 tselect file ebe geet eh 237 238 TYPE statement 138 139 147 158 types UO statements eee 138 User defined AA 212 U u compiler option 64 unaligned data locating EE 108 unformatted data order of precedence 127 unformatted direct files and Microsoft Fortran PowerSation compatibility 174 unformatted I O statement 139 unformatted sequential files and Microsoft Fortran PowerSation compatibility 174 Unicode ee EE 8 uninstall Sh gege 237 uninstall sh le 237 238 unit inquiry eebe 155 unit information OPEN statement specifiers for 152 unix preprocessor symbol 25 UNLOCK statement 06 138 unlocking aile 138 unroll compiler option 71 unset Commande 13 unsetenv Commande 13 USE IFPORT statement 229 use_asm compiler option 82 user defined types AMONG EE 212 USEROPEN routme 147 USEROPEN specifier in OPEN statement 164 user s guide NOW TE 3 user supplied OPEN procedures 164 using user s EIER hehehe eg 3 V v compiler option 64 MAUEREN eege 183 Index variable length record type 144 146 variable length recorde 170 variables displaying in debugoger 99 VARYING property 183 189 VAXD keyword sss
16. Documentation Information Some documentation has been moved In particular e The ntel Fortran User s Guide now has separate parts for Building Applications and Optimizing Applications e Intel Fortran language information previously described in the ntel Fortran Programmer s Reference including intrinsics procedures and directives is now described in the online Language Reference e All Intel Fortran language elements and library routines are described in this online help file allowing easy lookup of reference information Version 7 1 Features Not Available in Intel Visual Fortran Version 8 240 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications The following Intel Fortran Version 7 1 features are not available in Intel Visual Fortran Version 8 e IMPLICIT AUTOMATIC STATIC statements e The Intel Fortran 8 0 run time library system s ability to work with the Itanium processor simulator Run Time Error Messages The table below lists the errors processed by the Intel Fortran run time library RTL For each error the table provides the error number the severity code error message text condition symbol name and a detailed description of the errors To define the condition symbol values PARAMETER statements in your program include the following file opt intel_fc_80 include for_iosdef f As described in the table the severity of the message determines which of the following
17. Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Copyright 2003 2004 Intel Corporation Portions Copyright 2001 Hewlett Packard Development Company L P Document Number 253259 001 Disclaimer and Legal Information Information in this document is provided in connection with Intel products No license express or implied by estoppel or otherwise to any intellectual property rights is granted by this document EXCEPT AS PROVIDED IN INTEL S TERMS AND CONDITIONS OF SALE FOR SUCH PRODUCTS INTEL ASSUMES NO LIABILITY WHATSOEVER AND INTEL DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY RELATING TO SALE AND OR USE OF INTEL PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR PURPOSE MERCHANTABILITY OR INFRINGEMENT OF ANY PATENT COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT Intel products are not intended for use in medical life saving or life sustaining applications This Intel Fortran Compiler for Linux Systems User s Guide Volume I Building Applications as well as the software described in it is furnished under license and may only be used or copied in accordance with the terms of the license The information in this manual is furnished for informational use only is subject to change without notice and should not be construed as a commitment by Intel Corporation Intel Corporation assumes no responsibility or liability for any errors or inaccuracies that may app
18. Intel Fortran at run time implicitly opens preconnected units 5 6 and O and associates them with the following operating system standard UO files Unit Environment Variable Equivalent Linux Standard I O File 5 FORTS Standard input stdin 6 FORT6 Standard output stdout 0 FORTO Standard error stderr You can change these preconnected files by doing one of the following e Using an OPEN statement to open unit 5 6 or 0 When you explicitly OPEN a file for unit 5 6 or 0 the OPEN statement keywords specify the file related information to be used instead of the preconnected standard UO file e Setting the appropriate environment variable FORT n to redirect I O to an external file To redirect input or output from the standard preconnected files at run time you can set the appropriate environment variable or use the appropriate shell redirection character in a pipe such as gt or lt Opening Files OPEN Statement To open a file you should use a preconnected file Such as for terminal output or explicitly open files with an OPEN statement Although you can also implicitly open a file this prevents you from using the OPEN statement to specify the file connection characteristics and other information 150 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications OPEN Statement Specifiers The OPEN statement connects a unit number with an external fil
19. characters as shown in the following figure Formatted Records in a Formatted Sequential File Record N Record N 1 Ji WW An example of a program writing three records to a formatted sequential file is given below The resulting file is shown in the following figure 173 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications OPEN 3 FILE FSEQ FSEQ is a formatted sequential file by default WRITE 3 A I3 RECORD 1 WRITE 3 As WRITE 3 Al11 The 3rd One CLOSE 3 END Formatted Sequential File ytes data in Record 1 Sb 2 bytes CR LF separator 0 bytes data in Record 2 2 bytes CR LF separator 11 reien data in Record 3 Lo bytes CR LF separator 9 10111213 14 24 25 26 CES Gel Eed Hex RECO CES Gel OD AJOD QA A DD GA Formatted Direct Files In a formatted direct file all of the records are the same length and can be written or read in any order The record size is specified with the RECL option in an OPEN statement and should be equal to or greater than the number of bytes in the longest record The carriage return CR and line feed LF characters are record separators and are not included in the RECL value Once a direct access record has been written you cannot delete it but you can rewrite it During output to a formatted direct file if data does not completely fill a record the compiler pads the remaining por
20. e Uses ia to link the main program and all object files into an executable program file named calc Running the Sample Program If your path definition includes the directory containing calc you can run the program by simply entering its name calc When running the sample program the PRINT and READ statements in the main program result in the following dialogue between user and program Type five numbers 55 5 27 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications 4 5 3 9 9 0 5 6 Ave verage of the five numbers is 15 70000 Debugging the Sample Program To debug a program with the debugger compile the source files with the g option to request additional symbol table information for source line debugging in the object and executable program files The following ifort command also uses the o option to name the executable program file calc_debug ifort g o calc_debug array_calc f90 calc_aver f 90 main f90 See also Debugging Overview and related sections Creating Shared Libraries To create a shared library from a Fortran source file process the files using the ifort command e You must specify the shared option to create the so file e You can specify the o output option to name the output file e If you omit the c option you will create a shared library so file directly from the command line in a single step If you also omit the o output option the fi
21. e fpp Intel Fortran preprocessor fpp e f Intel Fortran compiler fortcom e c Intel C compiler e as Assembler e link Linker and options is one or more valid argument strings for the designated tool If the argument contains a space or tab character you must enclose the entire argument in quotation marks You must separate multiple arguments with commas The following example directs the linker to link with an alternative library ifort Qoption link lmylib progl f Predefined Preprocessor Symbols Preprocessor symbols macros let you substitute values in a program before it is compiled The substitution is performed in the preprocessing phase Some preprocessor symbols are predefined by the compiler system and are available to compiler directives and fpp If you want to use others you need to specify them on the command line See also Preprocessor Options The predefined preprocessor symbols available for the Intel Fortran compiler are described in the table below The Default column describes whether the preprocessor symbol is enabled on or disabled off by default Symbol Name Default Architecture Description __INTEL_COMPILER n Qn n 800 Both Identifies the Intel Fortran Compiler linux_ Both Defined at the start of EE compilation Onu Linux linux unix _ unix unix ELF __ i386 IA 32 23 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applicati
22. eeeeeeeeeeeeeeeeeeeeeeeneeeeeeeees 17 Parallel Invocation with a Makefile cccceeseceeeeeeeeeeenneeeeeeeeeeeeeeeeeeneeeeeeeees 18 Searching for Include and mod Files 19 Specifying and Removing an Include File Pat 19 Configuration Files and Response Files ssssnnnnseeesssesnnrnnrrnesserrrnrnneserrrrrnrnnneeeet 20 Config ration Ee tee 20 Example Configuration File eebe 21 PROSDONSE FIGS rites E Sa aes Ee 21 Specifying Alternative Tool Locations and Options seeeeeeeeeseesseeeeeeees 22 Using Qlocation to Specify an Alternative Location for a Tool 22 Table Of Contents Using Qoption to Pass Options to Tools sssseeseseseseeescsesesseeeeeeeeeeeeeeees 22 Predefined Preprocessor Gvmbols AAA 23 Defining Preprocessor Symbols ccccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeesenneeeeeeeees 24 Suppressing Preprocessor Symbols en 25 Redirecting Command Line Output to Files ccceeceeeeeeeeeeeeeneeeeeeeeeeeeeeeeeaaees 25 Creating Running and Debugging an Executable Program sseeeeee 25 Commands to Create a Sample Program ccceeeeeeeeeeeneeeeeeeeeeeeeeeenaees 26 Running the Sample Program EE 27 Debugging the Sample Program cecceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeseneeeeeeeeees 28 Creating Shared MET 28 Creating a Shared Library with a Single ifort Commande 28 Creating a Shared Library with ifort and Id Commande nnnnnn
23. ATTRIBUTES Properties and Calling Conventions cceeeeeeeeeeeeeeeeeees 182 Adjusting Naming Conventions in Mixed Language Programming 185 Adjusting Naming Conventions in Mixed Language Programming Overview 185 C C Naming Conventions ssssssssnneeneeeesssrerrttesetrtrnrnnnrrneerrtrrnnnnnnnnneernnnnn nnn 186 Procedure Names in Fortran C and Cie 187 Reconciling the Case of Names EE 187 Fortran Module Names and ATTRIBUTES cececceeeeneeeeeeeeeeeeeneeeeeeeeeeeeeeees 188 Prototyping a Procedure in Fortran AE 189 Exchanging and Accessing Data in Mixed Language Programming 190 Exchanging and Accessing Data in Mixed Language Programming Overview 190 Passing Arguments in Mixed Language Programming eeeeeeeeeeeeeeeeeees 191 Using Common External Data in Mixed Language Programming 66 193 Using Global Variables in Mixed Language Programming sssssssseeeeeesesseee 193 Using Fortran Common Blocks and C Structures A 194 Accessing Common Blocks and C Structures Diech 195 xix Table Of Contents Passing the Address of a Common Block 196 Handling Data Types in Mixed Language Programming sssseseeeeeesesssee 197 Handling Data Types in Mixed Language Programming Cverview 197 Handling Numeric Complex and Logical Data Tvpes 198 Returning Complex Type Data 199 Handling Fortran Array Pointers and Allocatable Aas 200 Handling Integer GE 20
24. Applications FIXEDFORMLINESIZE option extend_source option FREEFORM free Or nofixed NOFREEFORM nofree Or fixed INTEGER option integer_size option PACK option align option REAL option real_size option STRICT warn stderrors with stand NOSTRICT warn nostderrors Note that the compiler directive names above are specified using the prefix DECS followed by a space For example DECS NOSTRICT F Note The prefix DECS is normally used DEC works for both fixed form and free form source You can also use these alternative prefixes for fixed form source only cDEC CDEC DEC cCDIR CDIR DIRS and MSS Code Generation Options The code generation options let you specify how code should be generated Descriptions of Code Generation Options no recursive Default norecursive Compiles all procedures functions and subroutines for possible recursive execution When recursive is specified the auto option is also set noJreentrancy keyword Default noreent rancy Generates reentrant code that supports a multithreaded application The keyword can be e none Sameas noreentrancy Tells the Intel Fortran run time library RTL that the program will not be relying on threaded or asynchronous reentrancy Therefore the RTL will not guard against such interrupts inside its own critical regions 35 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications
25. Consider the following Fortran program PROGRAM complextest COMPLEX 8 C8 2 0 8 0 COMPLEX 16 C16 1 23 4 56 REAL 4 R4 2 0 REAL 8 R8 2 0 REAL 16 R16 2 0 TYPE C8 C8 103 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications TYPE Cl6 C16 END PROGRAM idb supports the display and assignment of COMPLEX variables and constants as well as basic arithmetic operators For example Welcome to the idb Debugger Version x x xx object file name complex Reading symbolic information done idb stop in complextest 1 stop in complextest idb run 1 stopped at complextest 15 0x1200017b4 15 TYPE C8 CH idb whatis c8 complex c8 idb whatis c16 double complex c16 idb print c8 2 8 idb print c16 1 23 4 56 idb assign c16 2 3E 10 4 5e 2 i idb print c16 23000000512 0 04500000178813934 Data Types The table below shows the Intel Fortran data types and their equivalent built in debugger names Fortran 95 90 data type declaration Debugger equivalent CHARACTER character INTEGER INTEGER KIND n integer integer n LOGICAL LOGICAL KIND n logical logical n REAL REAL KIND 4 real DOUBLE PRECISION REAL KIND 8 real 8 REAL KIND 16 real 16 COMPLEX COMPLEX KIND 4 complex DOUBLE COMPLEX COMPLEX KIND 8 double complex COMPLEX KIND 16 COMPLEX 32
26. Fortran Compiler for Linux Systems User s Guide Volume Building Applications Use the RECL specifier to specify the record length The units used for specifying record length depend on the form of the data e Formatted files FORM FORMATTED Specify the record length in bytes e Unformatted files FORM UNFORMATTED Specify the record length in 4 byte units unless you specify the assume byterec1 option to request 1 byte units For all but variable length sequential records on 64 bit addressable systems the maximum record length is 2 147 billion bytes 2 147 483 647 minus the bytes for record overhead For variable length sequential records on 64 bit addressable systems the theoretical maximum record length is about 17 000 gigabytes When considering very large record sizes also consider limiting factors such as system virtual memory Accessing and Assigning Files Most I O operations involve a disk file keyboard or screen display Other devices can also be used e Sockets can be read from or written to if a USEROPEN routine usually written in C is used to open the socket e Pipes opened for read and write access block wait until data is available if you issue a READ to an empty pipe e Pipes opened for read only access return EOF if you issue a READ to an empty pipe You can access the terminal screen or keyboard by using preconnected files Assigning Files to Logical Units You can choose to assign files t
27. align option for all compilations e The program might contain INTEGER LOGICAL REAL COMPLEX or DOUBLE PRECISION declarations without a kind parameter or size specifier that is passed or shared by module definition or common block You must consistently use the options that control the size of such numeric data declarations Using the OPTIONS Statement to Override Options You can override some options specified on the command line by using the OPTIONS statement in your Fortran source program The options specified by the OPTIONS statement affect only the program unit where the statement occurs Getting Help on Options For help enter help on the command line which displays brief information about all the command line options Compiler Directives Related to Options Some compiler directives and compiler options have the same effect as shown in the table below However compiler directives can be turned on and off throughout a program while compiler options remain in effect for the whole compilation unless overridden by a compiler directive Compiler directives and equivalent command line compiler options are Compiler Directive Equivalent Command Line Compiler Option DECLARE warn declarations NODECLARE warn nodeclarations DEFINE symbol Dname 34 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building
28. can then be run ifort file for o vconvert convert vaxd Because this method affects all unformatted file unit numbers you cannot read data in one format and write it in another file format using the convert keyword compiler option method alone You can if you use it in combination with the environment variable methods or the OPEN statement CONVERT keyword method to specify a different format for a particular unit number Porting Nonnative Data Keep this information in mind when porting nonnative data 134 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications e When porting source code along with the unformatted data vendors might use different units for specifying the record length RECL specifier of unformatted files While formatted files are specified in units of characters bytes unformatted files are specified in longword units for Intel Fortran default and some other vendors To allow you to specify the RECL units bytes or longwords for unformatted files without source file modification use the assume byterecl compiler option The Fortran 90 standard American National Standard Fortran 90 ANSI X3 198 1991 and International Standards Organization standard ISO IEC 1539 1991 in Section 9 3 4 5 states If the file is being connected for unformatted input output the length is measured in processor dependent units e Certain vendors apply different OPEN statement defau
29. fvisibility keyword or specifies the visibility for symbols that are in a file fvisibility keyword file This second form overrides the first form The keyword specifies what the visibility is set to Visibility can be set to any of the following e default Other components can reference the symbol and the symbol definition can be overridden preempted by a definition of the same name in another component e extern The symbol is treated as though it is defined in another component It also means that the symbol can be overridden by a definition of the same name in another component e hidden Other components cannot directly reference the symbol However its address might be passed to other components indirectly e internal The symbol cannot be referenced outside its defining component either directly or indirectly e protected Other components can reference the symbol but it cannot be overridden by a definition of the same name in another component The fileis the pathname of a file containing the list of symbols whose visibility you want to set The symbols are separated by whitespace spaces tabs or newlines g Default Off Generates symbolic debugging information and line numbers in the object file for use by debuggers help Displays brief information about all the command line options inline_debug_info Default Off Keeps the source position of inline code instead of assigning the call site so
30. idb s stopped at ptr 7 0x120001880 7 xp gt x idb s stopped at ptr 9 0x120001954 9 print x x idb s x 1 2 3 stopped at ptr 10 0x1200019c8 idb s xp 1 2 stopped at point 12 0x120001ad8 12 end idb S xp 1 2 3 idb whatis xp 2 int xp 1 3 idb print xp 1 1 2 2 3 3 idb quit 1 For the first whatis xp command xp has not yet been assigned to point to variable x and is a generic pointer 2 Since xp has been assigned to point to variable x for the second whatis xp command xp takes the same size shape and values as x Integer Pointers Like Fortran 95 90 pointers integer pointers also known as Cray style pointers display the target data in their corresponding source form with a print command idb stop at 14 1 stop at dfpoint 90 14 idb run 1 stopped at dfpoint 14 0x1200017e4 idb list 1 14 program dfpoint real i 5 pointer p i NOB WN EF n D 101 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications 7 8 p malloc sizeof i 1 n 9 10 do j 1 5 11 i j 10 35 12 end do 13 gt 14 end idb whatis p float 1 5 pointer p idb print p 0x140003060 1 10 2 20 3 30 4 40 5 50 idb quit Array Variables For array variables put subscripts within parentheses as with Fortran 95 90 source statements For example idb assign arrayc 1 1 You can print out all
31. message is issued and the next file if any on the command line is compiled openmp_report 0 1 2 Default Off openmp_report1 is the default if openmp_report Is specified without an argument Specifies the OpenMP parallelizer s diagnostic level where n is e 0 No information e 1 Loops regions and sections parallelized e 2 Same as 1 plus master construct single construct and so forth For more information see Parallelization with OpenMP Overview and related sections in the User s Guide Volume II Optimizing Applications par_report 0 1 2 3 Default Off par_reporti is the default if par_report is specified without an argument Specifies the autoparallelizer s diagnostic level where n is 41 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications 0 No information 1 Loops successfully parallelized 2 Loops successfully and unsuccessfully parallelized 3 Same as 2plus dependency information See also these topics in Volume II Auto Parallelization Overview Auto Parallelization Enabling Options Directives and Environment Variables Std std90 std95 Default Off no messages are issued Alternate syntax no stand or w90 or stand90 for Fortran 90 or w95 or stand95 for Fortran 95 std and stand and std95 and stand95 which are equivalent warn for nonstandard Fortran 95 std90 and stand90 which are equivalent warn for nonstandard Fortran 90
32. name of the file to open int open_flags access read READ WRITE see file h xf int create_mode access read set if new file to be created int lun access read logical unit number file opened on int file_length access read number of characters in file name Function Value Completion Code kk xx Whatever is returned by open is immediately returned to the Fortran OPEN The returned value is the following ER value gt 0 is a valid fd kx value lt 0 is an error kk Modify open flags logical OR to specify the file be opened for xx write access only with records appended at the end such as writing to a shared log file ae int result Function result value open_flags O_CREAT O_WRONLY O_APPEND result open file_name open_flags create_mode DH return result return file descriptor or error End of routine uopen_ 167 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications End of file uopen_ c Source Code for the Calling Intel Fortran Program The following example shows the Fortran program that calls the uopen_ C function and then performs I O C C Program EX1 opens a file using USEROPEN and writes records to it C It closes and re opens the file without USEROPEN and reads 10 records PROGRAM EX1 EXTERNAL U
33. which helps keep track of the variable between the two languages Obviously if a common block contains more than one variable they cannot all have the common block name See Using Fortran Common Blocks and C Structures Using Fortran Common Blocks and C Structures To reference C structures from Fortran common blocks and vice versa you must take into account the way the common blocks and structures differ in their methods of storing member variables in memory Fortran places common block variables into memory in order as close together as possible with the following rules e A single BYTE INTEGER 1 LOGICAL 1 or CHARACTER variable in common block list begins immediately following the previous variable or array in memory 194 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications e All other types of single variables begin at the next even address immediately following the previous variable or array in memory e All arrays of variables begin on the next even address immediately following the previous variable or array in memory except for CHARACTER arrays which always follow immediately after the previous variable or array e All common blocks begin on a four byte aligned address Because of these padding rules you must consider the alignment of C structure elements with Fortran common block elements and assure matching either by making all variables the same types and kinds in both language
34. 1 0001 01 1 2 0010 02 2 3 0011 03 3 4 0100 04 4 5 0101 05 5 238 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications 6 0110 06 6 7 0111 07 7 8 1000 10 8 9 1001 11 9 A 1010 12 10 B 1011 13 11 C 1100 14 12 D 1101 15 13 E 1110 16 14 F 1111 17 15 Compatibility with Previous Versions of Intel Fortran This topic is written for developers who are familiar with Intel Fortran Version 7 1 or earlier versions are now using Intel Fortran Version 8 Intel Fortran supports extensions to the ISO and ANSI standards including a number of extensions defined by e Intel Fortran for various platforms e Microsoft Fortran PowerStation 4 0 Many language extensions associated with Microsoft Fortran PowerStation Version 4 have been added to Intel Fortran Differences Between Intel Fortran Version 7 1 and Intel Fortran Version 8 Some differences are e The command name for command line use is now ifort Earlier versions of Intel Fortran used a command name of ifc or efc For Intel Fortran 8 0 these command names will still be accepted but in some future Intel Fortran release only the ifort command name will be accepted e The default configuration file name is now ifort cfg instead of ifl cfg orefl cfg 239 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications e The predefined symbol name for the Intel Fortran compiler is __INTEL_COMPILER and it
35. 16 hex 7 F9 hex INTEGER KIND 2 Representation INTEGER 2 values range from 32 768 to 32 767 and are stored in 2 contiguous bytes as shown below 15 BINARY NUMBER A zo j Zk Osoeot Integers are stored in a two s complement representation For example 22 0016 hex 7 FFF9 hex INTEGER KIND 4 Representation INTEGER 4 values range from 2 147 483 648 to 2 147 483 647 and are stored in 4 contiguous bytes as shown below al 20 U BINARY NUM BER A Zk 07S 5E zo 111 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Integers are stored in a two s complement representation INTEGER KIND 8 Representation INTEGER 8 values range from 9 223 372 036 854 775 808 to 9 223 372 036 854 775 807 and are stored in 8 contiguous bytes as shown below 63a Ge a Zk s254 E zo Integers are stored in a two s complement representation Logical Data Representations Logical data lengths can be 1 2 4 or 8 bytes in length The default data size used for a LOGICAL data declaration is LOGICAL 4 same as LOGICAL KIND 4 unless the integer_size 16 o0r integer_size 64 option was specified To improve performance on Itanium based systems use LOGICAL 4 or LOGICAL 8 rather than LOGICAL 2 or LOGICAL 1 LOGICAL KIND 1 values are stored in 1 byte In addition to having logical values TRUE and FALSE LOGICAL 1 data can also have values
36. 18 1 On the command line the g option directs the compiler to write the symbol information associated with SQUARES into the object file for the debugger It also disables most optimizations done by the compiler to ensure that the executable code matches the source code of the program 2 The shell command idb squares runs the debugger which displays its banner and the debugger prompt idb This command specifies the executable program as a file named squares You can now enter debugger commands After the idb squares command execution is initially paused before the start of the main program unit before program SQUARES in this example 3 The list 1 9 command prints lines 1 through 9 4 The command stop at 8 sets a breakpoint 1 at line 8 96 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications 5 The run command begins program execution The program stops at the first breakpoint line 8 allowing you to examine variables N and K before program completion 6 The step advances the program to line 9 The step command ignores source lines that do not result in executable code also by default the debugger identifies the source line at which execution is paused To avoid stepping into a subprogram use the next command instead of step 7 The command print n k displays the current values of variables N and K Their values are correct at this point in the execution of the program 8 The
37. 21 234 277 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications ein ch och alienate 13 ifortvars csh file 14 237 238 ifortvars Sh EE 13 ifortvars sh le 14 237 238 ifportlib a Wbrarm 229 implicitnone compiler option 64 implied OPEN 147 149 include files searching Tor 20 indirect command files See response fil S 008 21 information retrieval routines 230 inline_debug_info compiler option 64 input and output routines 230 INDUEMGS EE 9 input record transfer 0 162 INQUIRE statement 138 155 inquiry by file name ssneaaaan 155 inquiry by output item list 155 inquiry by UNIT EE 155 installing shared rares 30 INTEGER compiler directive 36 278 integer data representation INTEGER KIND 1 2 55 112 INTEGER KIND 2 00 113 INTEGER KIND 4 055 113 INTEGER KIND 8 5 113 OVONVIGW ivisvsiiecserexeccsorexercsorexest 112 integer pointer 99 203 INTEGER IKIND 8 data TeDresentaton 113 INTEGER KIND 1 data reDtesentaion 112 INTEGER KIND 2 data TeDresentaion 113 INTEGER KIND 4 data reDtesentaion 113 integer_size compiler option 47 INTERFACE wo viccsscscnclncaiuetieaaens 202 INTERFACE statement 190 internal files EE 143 intrinsic data Iwvpes 110 I
38. 5 is arr 4 4 not arr 5 5 The following table shows equivalencies for array declarations Equivalent Array Declarations for Different Languages Language Array Declaration Array Reference from Fortran Fortran DIMENSION vi k x i k Or type x i k C C type x k i x i 1 k 1 204 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Intel Fortran Array Descriptor Format For cases where Fortran 95 90 needs to keep track of more than a pointer memory address the Intel Fortran Compiler uses an array descriptor which stores the details of how an array is organized When using an explicit interface by association or procedure interface block Intel Fortran generates a descriptor for the following types of array arguments e Pointers to arrays array pointers e Assumed shape arrays Certain data structure arguments do not use a descriptor even when an appropriate explicit interface is provided For example explicit shape and assumed size arrays do not use a descriptor In contrast array pointers and allocatable arrays use descriptors regardless of whether they are used as arguments When calling between Intel Fortran and a non Fortran language such as C using an implicit interface allows the array argument to be passed without an Intel Fortran descriptor However for cases where the called routine needs the information in the Intel Fortran descriptor declare th
39. Building Applications Specifies that lines in fixed format files that contain a D in column 1 should be treated as source code not comment lines noJextend_source size Default noextend_source which implies 72 characters if extend_source is specified without a size the default becomes extend_source 132 Alternate syntax 72 80 132 Specifies the column number used to end the statement field in fixed form source files 72 80 or 132 When a size is specified that will be the last column parsed as part of the statement field Any columns after that will be treated as comments This option is valid only for fixed form files and it enables the fixed option no f66 Default nof66 use current Fortran standards semantics Alternate syntax 66 Specifies that the compiler should select FORTRAN 66 interpretations in cases of incompatibility Differences include the following e DO loops are always executed at least once e FORTRAN 66 EXTERNAL statement syntax and semantics are allowed e Ifthe OPEN statement STATUS specifier is omitted the default changes to STATUS NEW instead of STATUS UNKNOWN e Ifthe OPEN statement BLANK specifier is omitted the default changes to BLANK ZERO instead of BLANK NULL no free or no fixed Default File extension is used to determine format Alternate syntax FR is equivalent to free FI is equivalent to fixed Specifies the format of the Fortran source code If this
40. Different Fortran calling conventions can be specified by declaring the Fortran procedure to have certain attributes Assume this example INTERFACE SUBROUTINE MY_SUB I DECS ATTRIBUTES C ALIAS My_Sub_ MY_SUB ia32 systems INTEGER I END SUBROUTINE MY_SUB END INTERFACE This code declares a subroutine named my_sug with the C property and the external name My_sub_ set with the ALIAS property For another example the following declaration assumes the subroutine is called with the C calling convention SUBROUTINE CALLED_FROM_C A 182 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building DECS ATTRIBUTES C INTEGER A CALLI ED_FROM_C Applications The following table summarizes the effect of the most common Fortran calling convention directives Calling Conventions for ATTRIBUTES Properties Argument Scalar Scalar value Scalar reference String String value String reference Array Array value Array reference Derived Type Derived Type value Derived Type reference F90 Pointer F90 Pointer value F90 Pointer reference Default Reference Value Reference Reference either Len End or Len Mixed Error Reference either No Len or Len Mixed Reference Error Reference Reference Value size dependent Reference Descri
41. Extensions La Note 13 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Options on the command line apply to all files For example in the following command line the c and nowarn options apply to both files x and vw E ifort c x f nowarn y f Using the make Command To compile a number of files with various paths and to save this information for multiple compilations you can use a makefile to invoke the Intel Fortran Compiler To use a makefile to compile your input files make sure that usr bin and usr local bin are in your path If you use the C shell you can edit your cshrc file and add the following setenv PATH usr bin usr local bin yourpath Then you can compile as make f yourmakefile where f is the make command option to specify a particular makefile Examples of the ifort Command Compiling and Linking Multiple Files The following ifort command compiles the Fortran free format source files aaa f90 bbb 90 and ccc 90 The command invokes the 1d linker and passes the temporary object file to the linker which it uses to produce the executable file a out ifort aaa f 90 bbb 90 ccc 90 The following ifort command compiles all file names that end with f as Fortran fixed format source The linker produces the a out file ifort f Preventing Linking Intel Fortran Compiler for Linux Systems User s Guide Volume l Building A
42. I O files if the corresponding FORTn environment variable is not set Types of I O Statements The table below lists the Intel Fortran I O statements Category and statement name Description File connection OPEN Connects a unit number with an external file and specifies file connection characteristics CLOSE Disconnects a unit number from an external file File inquiry DEFINE FILE Specifies file characteristics for a direct access relative file and connects the unit number to the file similar to an OPEN statement Provided for compatibility with compilers older than FORTRAN 77 INQUIRE Returns information about a named file a connection to a unit or the length of an output item list Record position BACKSPACE Moves the record position to the beginning of the previous record Sequential access only DELETE Marks a record at the current record position in a relative file as deleted direct access only ENDFILE Writes an end of file marker after the current record sequential access only FIND Changes the record position in a direct access file Provided for compatibility with compilers older than FORTRAN 77 REWIND Sets the record position to the beginning of the file sequential access only Record input READ Transfers data from an external file record or an internal file to internal storage UNLOCK Frees a record in a relative or sequential f
43. IEEE style X_float for REAL KIND 16 and COMPLEX KIND 16 NATIVE No conversion occurs between memory and disk This is the default for unformatted files VAXD Native little endian integers of the appropriate INTEGER size one two four or eight bytes and the following little 124 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications endian VAX proprietary floating point formats e VAX F_float for REAL KIND 4 and COMPLEX KIND 4 e VAX D_float for REAL KIND 8 and COMPLEX KIND 8 e VAX H_float for REAL KIND 16 and COMPLEX KIND 16 VAXG Native little endian integers of the appropriate INTEGER size one two four or eight bytes and the following little endian VAX proprietary floating point formats e VAX F_float for REAL KIND 4 and COMPLEX KIND 4 e VAX G_float for REAL KIND 8 and COMPLEX KIND 8 e VAX H_float for REAL KIND 16 and COMPLEX KIND 16 When reading a nonnative format the nonnative format on disk is converted to native format in memory If a converted nonnative value is outside the range of the native data type a run time message is displayed Limitations of Numeric Conversion The Intel Fortran floating point conversion solution is not expected to fulfill all floating point conversion needs For instance data fields in record structure variables specified in a STRUCTURE statement and data components of deriv
44. P IA 32 systems on 70 COMPpPlex MMS C ee zie sa ae eis e ee i ee a 71 STO JAAS cl nt Ga St lee ale ltt ale arare r aara aeie 71 Steechen 71 GE 71 fnsplit Itanium based systems only 72 fp IA 32 systems e EE 72 e O E E E E E 72 le 73 APS 11 ENT a Uu D 73 ip_no_pinlining IA 32 systems only 73 lee EE 73 IPO Orern robes non renee een E eek T nae 73 61 aR 0 0 Seen ee ae In ne arte eg rt Ie ee eee ee 74 PIOUS EE 74 ivdep_parallel Iltanium based systems only 74 ev elle Su a 74 sD KEE 74 OPE TODOMT E 75 OPt report TG TNCs cocci tcc eege ap aaa aii 76 OPE NOPOUL e EE 76 opt_report_level min Med May AAA 76 elen PhaSe PNAS EE 76 Table Of Contents Opt_report_routine routine 2 0 0 eee cece eeeeee cece eeeeeeeeeeeeeeeeeeeeeeeeeeaeeeeeeeess 76 Parthreshold e EE 77 Wal alleles tact A AA AE tan peste aetna lta li te aleaeten 77 prefetch IA 32 systems on een 77 SR CLT SUE eebe 78 SPOOL ANS WG xs ccc a a a care ile ater olite elle Cale tac 78 lee EE 78 Prof EE 78 scalar_rep IA 32 systems on 79 lee EE 79 Uro ts cacstend hatte cst tect E eha cui Aletha Al ala nual a 79 x K W N B P IA 32 systems on 79 Output Piles EE 80 Descriptions of Output Files Options ssssssennnnneeeeeesenrrrnrrerrrrnnnnneseerrrrennn 80 BA ha sas sieht gl ge gi ig al aes earn Sierra S 80 Ee E DEE 80 SEET 81 f no verbose asm WEE 81 SEELEN 81 AONMEMANNG Ee 81 SI RTL 81 S ch ele TD
45. Procedures Options EE 52 Descriptions of External Procedures Options eceeeeeeeeeeeeeeeeeeeeeeeeeeeees 52 assume no underscore core a Cea ae a At ea 52 SBOP EE the len Ar DEEN 52 Mames ege WEE 53 Floating PoM Al e EE 53 Descriptions of Floating Point Options seier 53 sASSUIMGE No MINUSO EE 53 lat ele ene EE 54 vi Table Of Contents fp_port IA 32 systems on 54 SHIT FITS e AEN esiis a Ea aAa Nl cas Na ia Dae its Nit ls Me i 55 SUG see lee eats erte eren Eet Eeer eels mutate ater 55 fpstkchk IA 32 systems Only eceeceecccceeeeeeeeeessseeeeeeeeeeeeeeeteseeeeeeeeeees 56 fr32 Itanium based systems on 56 IZ E E 56 IPF_flt_eval_method0 Itanium based systems only eeeeeeeeeees 56 PF_fltacc Itanium based systems on 57 IPF_fmal Itanium based systems Only eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 57 IPF_fp_speculationmode Itanium based systems on 57 SIND EE 57 pc 32 64 80 IA 32 systems oh 58 LANG WAG lee 58 Descriptions of Language Options ccccceeeeeeeeeeeeeeeeeneeeeeeeeeeeeeeesneneeeeeeeees 58 Sli ue 58 SONG Te 58 no extend_source SIZE EE 59 lee 59 no freeor nofi ked aeaea Ea ie las Ee EEEa 59 openmp Bee ue Re EE 60 Slieile e er 60 lee ee 60 Descriptions of Libraries Option E 60 vii Table Of Contents Bf FL elen GE 60 VOC T ACES ict ate as aaea ah alate At a ats Na ld A es 61 Ee ie le le 61 SE EE 61 e
46. SINGLE PRECISION and defines COMPLEX declarations constants functions and intrinsics as COMPLEX KIND 4 COMPLEX Alternate syntax None See Also REAL KIND 4 REAL Representation COMPLEX KIND 4 COMPLEX Representation 50 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications e nis 64 Defines REAL declarations constants functions and intrinsics as REAL KIND 8 DOUBLE PRECISION and defines COMPLEX declarations constants functions and intrinsics as COMPLEX KIND 8 DOUBLE COMPLEX Specifying real_size 64 causes intrinsic functions to produce a REAL KIND 8 or COMPLEX KIND 8 result instead of a REAL KIND 4 or COMPLEX KIND 4 result unless the argument is explicitly typed as REAL KIND 4 or COMPLEX KIND 4 including CMPLX FLOAT REAL SNGL and AIMAG For instance references to the CMPLX intrinsic produce DCMPLX results COMPLEX KIND 8 unless the argument to CMPLX is explicitly typed as REAL KIND 4 REAL 4 COMPLEX KIND 4 or COMPLEX 8 In this case the resulting data type is COMPLEX KIND 4 Alternate syntax r8 or autodouble See Also REAL KIND 8 DOUBLE PRECISION Representation COMPLEX KIND 8 DOUBLE COMPLEX Representation e nis 128 Defines REAL declarations constants functions and intrinsics as REAL KIND 16 and defines COMPLEX declarations constants functions and intrinsics as COMPLEX KIND 16 Alternate syntax r16 See Also REAL KIND 16 Represe
47. This option issues compile time messages for language elements that are not standard in the Fortran language that can be identified at compile time w90 and w95 turn off warnings for nonstardard Fortran for Fortran 90 and Fortran 95 respectively stand Is Set if you specify warn stderrors vec_report 0 1 2 3 4 5 IA 32 systems only Default Off vec_reporti is the default if vec_report is specified without an argument Specifies the vectorizer s diagnostic level where n is 0 No information 1 Indicate vectorizer loops 2 Indicate vectorizer and nonvectorizer loops 3 Indicate vectorizer loops plus dependence information 4 Indicate nonvectorized loops 5 Indicate nonvectorized loops plus the reason why they were not vectorized 42 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications For more information see Vectorization Overview and related sections in the User s Guide Volume II Optimizing Applications warn all or warn none or nowarn Default Custom individually specified Specifies the compiler diagnostics level Choices are e warn all show all diagnostics e warn none show no diagnostics Specifying warn all requests all possible warning messages but does not set warn errors Of warn stderrors To enable all the additional checking to be performed and force the severity of the diagnostics to be severe enough to not generate an object file specify warn al
48. Trailing Subrecord 1 User Data Sign bit 0 Applications Trailing Length Subrecords 2 to N 1 User Data Field Sign bit 1 Trailing Subrecord N User Data Sign bit 1 4 Subrecord length from length field 4 Files written with variable length records by Intel Fortran programs usually cannot be accessed as text files Instead use the Stream_LF record format for text files with records of varying length Segmented Records A segmented record is a single logical record consisting of one or more variable length unformatted records in a sequentially organized disk file Unformatted data written to sequentially organized files using sequential access is stored as segmented records by default Segmented records are useful when you want to write exceptionally long records but cannot or do not wish to define one long variable length record perhaps because virtual memory limitations can prevent program execution By using smaller segmented records you reduce the chance of problems caused by virtual memory limitations on systems on which the program may execute For disk files the segmented record is a single logical record that consists of one or more segments Each segment is a physical record A segmented logical record can exceed the absolute maximum record length 2 14 billion bytes but each segment physical record individually cannot exceed the maximum record length To access an unformatted s
49. a time The files are found in this 11 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications directory opt intel_fc_80 bin See Running the Shell Script to Set Up the Environment Variables within the C Shell use the setenv command to set an environment variable setenv FORTS usr users smith test dat To remove the association of an environment variable and its value within the C shell use the unsetenv command unsetenv FORT8 Within the Bourne shell sh the Korn shell ksh and the bash shell use the export command and assignment command to set the environment variable export FORT8 FORT8 usr users smith test dat To remove the association of an environment variable and its value within the Bourne shell the Korn shell or the bash shell use the unset command unset FORTS Configuration File Environment Variables By default the compiler picks up the default configuration file i fort cfg from the same directory where the compiler executable resides However if you want the compiler to use another configuration file in a different location you can use the IFORTCFG environment variable to assign the directory and filename for the other configuration file See Also Compile Time Environment Variables Run Time Environment Variables Running the Shell Script to Set Up the Environment Variables Before you first invoke the compiler you need to set the environmen
50. accumulated in the buffer If you specify assume buffered_io records accumulate in the buffer For disk devices assume buffered_io or the equivalent OPEN statement BUFFERED YES specifier or the FORT_BUFFERED run time environment variable requests that the internal buffer will be filled possibly by many record output statements WRITE before it is written to disk by the Fortran run time system If a file is opened for direct access I O buffering will be ignored 69 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Using buffered writes usually makes disk I O more efficient by writing larger blocks of data to the disk less often However if you request buffered writes records not yet written to disk may be lost in the event of a system failure Unless you set the FORT_BUFFERED environment variable to true the default is BUFFERED NO and assume nobuffered_io for all I O in which case the Fortran run time system empties its internal buffer for each WRITE or similar record output statements The OPEN statement BUFFERED specifier applies to a specific logical unit In contrast the assume no buffered_io option and the FORT_BUFFERED environment variable apply to all Fortran units auto_ilp32 Itanium based systems only Default Off Allows the compiler to use 32 bit pointers whenever possible as long as the application does not exceed a 32 bit address space Becaus
51. are used It is recommended that you place 1ibimf a in the first directory specified in the LD_LIBRARY_PATH variable The libimf aand 1ibm a libraries are always linked with Fortran programs For example if you place a library in directory perform set the LD_LIBRARY_PATH variable to specify a list of directories containing all other libraries separated by semicolons libimf a on the IA 32 Compiler For the IA 32 compiler 1ibimf a contains both generic math routines and versions of the math routines optimized for special use with the Intel Pentium 4 and Intel Xeon processors libimf a on the Itanium Based Compiler For the Itanium based compiler 1ibimf a is optimized for use with the Itanium architecture The compiler provides inlined versions of math library primitives and schedules the generated code with surrounding instructions This can improve the performance of typical floating point applications Reference Information Compile Time Environment Variables The compile time environment variables are e FPATH The path for include and module files e IFORTCFG The configuration file to use instead of the default configuration file 232 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications e LD_LIBRARY_PATH The path for shared sol library files e PATH The path for compiler executable files e TMP TMPDIR TEMP Specifies the directory in which to store
52. command shows how to delete a previously set breakpoint with event number 1 For instance you might need to delete a previously set breakpoint before you use the rerun command e The rerun command runs the program again Since there are no breakpoints the program runs to completion e The quit command exits the debugger and returns to the shell Other Debugger Commands Other debugger commands include the following e To get help on debugger commands enter the help command e To display previously typed debugger commands enter the history command e To examine the contents of a location use the print or dump commands e To execute a shell command use the sh command followed by the desired shell commana For instance if you cannot recall the name of a FUNCTION statement the following grep shell command displays the lines containing the letters FUNCTION allowing use of the function name SUBSORT in the stop in command 90 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications idb sh grep FUNCTION data for INTEGER 4 FUNCTION SUBSORT A B idb stop in subsort idb See also Summary of Debugger Commands Summary of Debugger Commands The table below lists some of the more frequently used debugging commands available in idb Many of these commands can be abbreviated for example you can enter c instead of cont and s instead of step You can use the alias command
53. common subexpressions and expansion of integer multiplication and division using shifts 03 Maximize speed plus use higher level optimizations optimizations include loop transformation software pipelining and IA 32 only prefetching this option may not improve performance for some programs Specifying 03 includes the optimizations performed by 02 This option enables additional global optimizations that improve speed at the cost of extra code size These optimizations include o Loop unrolling including instruction scheduling o Code replication to eliminate branches o Padding the size of certain power of two arrays to allow more efficient cache use See also this topic in Volume II Using Arrays Efficiently Setting 03 sets fp On IA 32 systems 01 02 and oO are equivalent On Itanium based systems 02 and o are equivalent S Note The last On option specified on the command line takes precedence over any others opt_report Default Off 75 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Generates an optimization report to stderr See also this topic in Volume It Optimizer Report Generation opt_report_file file Default Off Generates an optimization report and specifies the file name for the report You do not need to specify opt_report if you use this option See also this topic in Volume II Optimizer Report Generation opt_report_help D
54. consist of uppercase and lowercase letters For example the following file names represent three different files myfile for MYfile for MYFILE for The output produced by the ifort command includes e An object file such as test o if you specify the c option on the command line An object file is created for each source file e An executable file Such as a out if you omit the c option e One or more module files Such as datadef moa if the source file contains one or more MODULE statements You control the production of these files by specifying the appropriate options on the command line The compiler generates a temporary object file for each source file unless you specify the c option The linker is then invoked to link the object files into one executable program file and the temporary object files are deleted If you specify the c option the object files are created and retained in the current working directory You must link the object files later by using a separate ifort command This allows incremental compilation of a large application perhaps by means of a makefile processed by the make command If fatal errors are encountered during compilation or if you specify certain options such as c linking does not occur 5 Note To compile all objects over the entire program use the ipo option To specify a file name for the executable program file other than a out use the o output Option where
55. converts big endian format to little endian format Little to Big Endian Conversion Environment Variable In order to use the little endian to big endian conversion feature specify the numbers of the units to be used for conversion purposes by setting the F_UFMTENDIAN environment variable Then the READ WRITE statements that 129 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications use these unit numbers will perform relevant conversions Other READ WRITE statements will work in the usual way In the general case the variable consists of two parts divided by a semicolon No spaces are allowed inside the F_UFMTENDIAN value The variable has the following syntax F_UFMTENDIAN MODE MODE EXCEPTION where MODE big little EXCEPTION big ULIST little ULIST ULIST ULIST U ULIST U U decimal decimal decimal e MODE defines current format of data represented in the files it can be omitted The keyword little means that the data has little endian format and will not be converted This is the default The keyword big means that the data has big endian format and will be converted e EXCEPTION is intended to define the list of exclusions for MODE EXCEPTION keyword little or big defines data format in the files that are connected to the units from the EXCEPTION list This value overrides MODE value for the units liste
56. e 6 Optimize for Intel Pentium Pro Pentium Il and Pentium III processors IA 32 systems only e 7 Optimize for Intel Pentium 4 Intel Xeon Intel Pentium M processors and Intel Pentium 4 processors with Streaming SIMD Extensions 3 SSE3 instruction support IA 32 systems only unroll n Default unro11 lets the compiler decide Specifies the maximum number of times to unroll a loop Possible values are e unroll Lets the compiler decide e unroll0 Disables loop unrolling Note This is the only value allowed on Itanium based systems all other values are ignored e unrolln Sets nas the maximum number of times a loop can be unrolled x K W N B P IA 32 systems only 79 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Default None Lets you target your program to run on a specific Intel processor The resulting code might contain unconditional use of features that are not supported on other processors Possible values and the processors the code is optimized for are xK Intel Pentium III and compatible Intel processors xW Intel Pentium 4 and compatible Intel processors xN Intel Pentium 4 and compatible Intel processors xB Intel Pentium M and compatible Intel processors xP Intel Pentium 4 processors with Streaming SIMD Extensions 3 SSE8 instruction support To execute the program on x86 processors not provided by Intel Corporation
57. e E EN QOPtlOn TOOL ee EEE ER xi Table Of Contents So EE EE EE EE Ee 82 Tole StS eS EE 82 IN Eltere 82 Descriptions of Preprocessor Options EE 82 assume no source_include AEN 82 Drame E TT E 83 SIO Doce eet tei tee nie a ee te ee et 83 ee e 83 preDhOCeSS lr 84 SHEET 84 VV eidele ee EE 84 Run Time a 0 0 E 85 Descriptions of Run Time Oplons E 85 no check all or no check NONE eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeneeeeeeeeees 85 check noJarg_temp_ created Aessen 85 check Ile in 85 SEET Stearn Aa AeA eA A Ae a 86 check no output_conversion E 86 Moltrac baCk noireiiro mnra e E EE Rea EE E EET 86 Debugging USING OD EE 87 Debugging Using idb OVE E EE 87 Getting Started with Debugging EE 87 Debugging OPUN EE 88 xii Table Of Contents Preparing Your Program for D DUQQING eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeteees 88 Using Debugger Commands and Setting Breakpoints nnnnnnnneeeeeeneeneeeenen 89 Other Debugger Commande ENEE 90 Summary of Debugger Commande 91 Debugging the SQUARES Example Program ceccceeeeeeeeeeeeeeeeeeeeeeeeeeeeee 93 Displaying Variables in the Debugger sssssssssrsrnesssserrrrrrnrrssserrnnnnnnnnnsseennna 98 Module Ee 98 Common RETTEN 98 Derived Type V ANADISS saiinscccesiescctd ues coesie cetetiiced atc cade ce dent sud tulle EE 99 Lee ENEE 100 Pointer VallaDIOS s ee 100 Fortran 95 90 Pointers jeccscccceetr
58. e async Tells the RTL that the program may contain asynchronous handlers that could call the RTL This causes the RTL to guard against asynchronous interrupts inside its own critical regions e threaded Tells the RTL that the program is multithreaded This causes the RTL to use thread locking to guard its own critical regions Specifying threads sets reentrancy threaded since multithreaded code must be reentrant Specifying reentrancy Is equivalent to specifying reent rancy threaded sox IA 32 systems only Default sox Enables saving of the compiler options and version in the executable This option has no effect in Itanium based systems Compatibility Options The compatibility options let you specify how to make your source files and data files compatible with older Fortran versions or other operating systems such as big endian unformatted data files OpenVMS systems run time behavior and Microsoft Fortran PowerStation See Also Data Options Language Options Descriptions of Compatibility Options 1 Default Off Alternate syntax onetrip Specifies that the compiler should execute DO loops at least once See also no 66 36 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications assume no bscc Default assume nobscc Alternate syntax nbs is the same aS assume bscc Tells the compiler to treat the backslash character as a C style control escape ch
59. elements of an array using its name For example 1 1 Avoid displaying all elements of a large array Instead display specific array elements or array sections For example to print array element arrayc 2 idb print arrayc 2 2 0 Array Sections An array section is a portion of an array that is an array itself An array section can use subscript triplet notation consisting of a three parts a starting element an ending element and a stride Consider the following array declarations 102 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications NTEGER DIMENSION 0 99 sf arr NTEGER DIMENSION 0 4 0 4 FiveByFive Assume that each array has been initialized to have the value of the index in each position for example FiveByFive 4 4 44 arr 43 43 The following examples are array expressions that will be accepted by the debugger idb print arr 2 idb print arr 0 9 2 rint FiveByFive 3 lol UI Im oo b i i 3 k 2 3 4 WWW W The only operations permissible on array sections are whatis and print Assignment to Arrays Assignment to array elements are supported by idb For information about assigning values to whole arrays and array sections see the Fortran chapter in the online Intel Debugger IDB Manual Complex Variables idb supports COMPLEX or COMPLEX 8 COMPLEX 16 and COMPLEX 32 variables and constants in expressions
60. files that should be included in the program You can use the module path option to specify the directory where to create the module files This path is also used to locate module files If you don t use this option module files are created in the default path You need to make sure that the module files are created before they are referenced by another program or subprogram Compiling Programs with Modules If a file being compiled has one or more modules defined in it the compiler generates one or more mod files For example a file a 90 contains modules defined as follows module test integer a contains subroutine f end subroutine end module module payroll 16 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications end module This compiler command ifort c a f 90 generates the following files test mod test o payroll mod payroll o The mod files contain the necessary information regarding the modules that have been defined in the program a 90 If the program does not contain a module no mod file is generated For example test2 90 does not contain any modules This compiler command ifort c test2 f90 produces just an object file test 2 0 For another example assume that file1 f 90 contains one or more modules and file2 f90 contains one or more program units that access these modules with the USE statement The sources can be c
61. has a value of 800 e The record length RECL specifier for unformatted files is now 32 bit words To get the record length in bytes use the assume byterecl option e The backslash character is not treated as an escape character for control sequences in character literals To force the backslash to start escape sequences use the assume bscc option e Intel Fortran Version 8 by default uses the integer 1 for the value of TRUE whereas Version 7 uses the integer 1 for the value of TRUE If you use the fpscomp logicals option with Version 8 the compiler will use the integer 1 for the value of TRUE Version 8 always uses the integer 0 as the value of FALSE as did Version 7 User written routines in Fortran or other languages for example C need to insure that they use values for TRUE and FALSE consistent with the compiler s choice e The random number generator used in Version 8 is different from the random number generator used in Version 7 Version 8 uses the random number generator based on the algorithm of Park and Miller which is the generator used by Compag Fortran Version 7 used the Marsaglia random number generator Both of these random number generators are compatible with the Fortran 90 standard In addition Version 8 uses different algorithms for the RANDOM_NUMBER and RANDOM _SEED intrinsics compared to Version 7 and different algorithms are used for these intrinsics on IA32 and Itanium based systems
62. in the range 128 to 127 Logical variables can also be interpreted as integer data In addition to LOGICAL 1 logical values can also be stored in 2 LOGICAL 2 4 LOGICAL 4 or 8 LOGICAL 8 contiguous bytes starting on an arbitrary byte boundary If the fpscomp nological compiler option is set the default the low order bit determines whether the logical value is true or false Specify fpscomp logical for Microsoft Fortran PowerStation logical values where 0 zero is false and non zero values are true LOGICAL 1 LOGICAL 2 LOGICAL 4 and LOGICAL 8 data representation when fpscomp nological option was set appears below Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications TRUE UNDEFINED BITS FALSE UNDEFINED BITS A kl S S fo jo Lae D ke n 7 15 31 0768 de pending on LOGICAL declaration sin ZE Sa E Native IEEE Floating Point Representations Native IEEE Floating Point Representations Overview The REAL 4 IEEE S_floating REAL 8 IEEE T_floating and REAL 16 IEEE style X_floating formats are stored in standard little endian IEEE binary floating point notation See IEEE Standard 754 for additional information about IEEE binary floating point notation COMPLEX formats use a pair of REAL values to denote the real and imaginary parts of the data All floating point formats represent fractions in sign magnitude notation with the binary radi
63. input statement should not specify more data fields than the record contains e For formatted input using nonadvancing I O ADVANCE NO an end of record EOR condition is returned If the file was opened with PAD YES additional fields are read as spaces e For list directed input another record is read e For NAMELIST input another record is read e For unformatted input an error occurs Output Record Transfer If an output statement specifies fewer data fields than the record contains less data than required to fill a record the following occurs e With fixed length records RECORDTYPE FIXED all records are the same size If the size of an I O record being written is less than the record length RECL extra bytes are added padding in the form of spaces for a formatted record or zeros for an unformatted record e With other record types the fields present are written and those omitted are not written might result in a short record If the output statement specifies more data than the record can contain an error occurs as follows e With formatted or unformatted output using fixed length records if the items in the output statement and its associated format specifier result in a number of bytes that exceeds the maximum record length RECL an error occurs e With formatted or unformatted output not using fixed length records if the items in the output statement and its associated format specifier re
64. length for direct access and relative organization files The buffer size is increased by 1 to accommodate the deleted record character e Reading deleted records and ENDFILE records The run time direct access READ routine checks the first byte of the retrieved record If this byte is or NULL 0 then an ATTACCNON error is returned The run time sequential access READ routine checks to see if the record it just read is one byte long and contains a Ctrl Z If this is true it returns EOF Compilation Diagnostics Options The compilation diagnostics options let you specify the kinds of diagnostic messages warnings and errors you want to receive 40 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Descriptions of Compilation Diagnostics Options e90 or e95 Default Off Alternate syntax w90 or w95 Issues errors for nonstandard Fortran 90 e90 or nonstandard Fortran 95 e95 This option issues compile time errors for language elements that are not standard in the Fortran language that can be identified at compile time 00 See also no stand noJerror_limit n Default error_limit 30 Specifies the maximum number of error level or fatal level compiler errors allowed for a given file before compilation aborts If you specify noerror_limit onthe command line there is no limit on the number of errors that are allowed If the maximum number of errors is reached a warning
65. length of a REAL or a COMPLEX declaration using a kind parameter or specify DOUBLE PRECISION or DOUBLE COMPLEX To control the size of all DOUBLE PRECISION and DOUBLE COMPLEX declarations use the double_size 128 option the default is double_size 64 The following sections discuss floating point data REAL KIND 4 Single Precision Representation REAL KIND 8 Double Precision Representation REAL KIND 16 Extended Precision Representation COMPLEX KIND 4 Single Precision Representation COMPLEX KIND 8 Double Precision Representation COMPLEX KIND 16 Representation For information on reading or writing floating point data other than native IEEE little endian data see Converting Unformatted Numeric Data See also File fordef for and Its Usage REAL KIND 4 REAL Representation REAL 4 same as REAL KIND 4 data occupies 4 contiguous bytes stored in IEEE S _ floating format Bits are labeled from the right 0 through 31 as shown below a1 30 aa 22 a EXPONENT FRACTION A H ZK SH GE The form of REAL 4 data is sign magnitude with bit 31 the sign bit 0 for positive numbers 1 for negative numbers bits 30 23 a binary exponent in excess 127 notation and bits 22 0 a normalized 24 bit fraction including the redundant most significant fraction bit not represented 114 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications The value of data is in the approximate range 1
66. lf a Fortran program expects a function to return data of type CHARACTER the Fortran compiler adds two additional arguments to the beginning of the called procedure s argument list e The first argument is a pointer to the location where the called procedure should store the result e The second is the maximum number of characters that must be returned padded with white spaces if necessary The called routine must copy its result through the address specified in the first argument Example that follows shows the Fortran code for a return character function called MAKECHARS and corresponding C routine Example of Returning Character Types from C to Fortran Fortran code CHARACTER 10 CHARS MAKECHARS DOUBLE PRECISION X Y CHARS MAKECHARS X Y Corresponding C Routine void makechars result length x y char result int length double x y program text producing returnvalue for i 0 i lt length i result i returnvalue il In the above example the following restrictions and behaviors apply e The function s length and result do not appear in the call statement they are added by the compiler e The called routine must copy the result string into the location specified by result it must not copy more than length characters e If fewer than length characters are returned the return location should be padded on the right with blanks Fortran does not u
67. n x y CALL initcb n 196 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications C source code pragma pack 2 struct block_type int n double x double y l pragma pack void initcb struct block_type block_hed block_hed gt n 1 block_hed gt x 10 0 block_hed gt y 20 0 Handling Data Types in Mixed Language Programming Handling Data Types in Mixed Language Programming Overview Even when you have reconciled calling conventions naming conventions and methods of data exchange you must still be concerned with data types because each language handles them differently The following table lists the equivalent data types between Fortran and C Equivalent Data Types Fortran Data C Data Type ee d REAL 4 float REAL 8 double 197 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications GE SE CHARACTER 1 unsigned char unsigned char CHARACTER See Handling Character Strings COMPLEX 4 struct complex4 float real imag IL COMPLEX 8 struct complex8 double real imag COMPLEX 16 16 All LOGICAL ry integer types for types See these topics Handling Numeric Complex and Logical Data Types Handling Fortran Array Pointers and Allocatable Arrays Handling Intel Fortran Pointers Handling Arrays and Fortran Array Descri
68. number This method requires an explicit file OPEN statement to specify the numeric format of the file for that unit number This method takes precedence over the OPTIONS statement and the compiler option convert keyword method but has a lower precedence than the environment variable methods For example the following source code shows how the OPEN statement would be coded to read unformatted VAXD numeric data from unit 15 which might be processed and possibly written in native little endian format to unit 20 Tthe absence of the CONVERT keyword or environment variables FORT_CONVERT20 132 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications FORT_CONVERT dat FORT_CONVERT_dat Or F_UFMTENDIAN indicates native little endian data for unit 20 OPEN CONVERT VAXD FILE graph3 dat FORM UNFORMATTED UNIT 15 OPEN FILE graph3_t dat FORM UNFORMATTED UNIT 20 A hard coded OPEN statement CONVERT keyword value cannot be changed after compile time However to allow selection of a particular format at run time equate the CONVERT keyword to a variable and provide the user with a menu that allows selection of the appropriate format menu choice sets the variable before the OPEN occurs You can also select a particular format at run time for a unit number by using one of the environment variable methods FORT_CONVERTn FORT_CONVERT ext FORT_CONVERT_ ext or
69. number and source file are given The verbose output if selected will provide in addition to the information in brief output the exception context record if the error was a machine exception machine register dump and for each frame the return address frame pointer and stack pointer and possible parameters to the routine This output can be quite long but limited to 16K bytes and use of the environment variable FOR_DIAGNOSTIC_LOG_FILE is recommended if you want to capture the output accurately Most situations should not require the use of verbose output The variable FOR_ENABLE_VERBOSE_STACK_TRACE is also recognized for compatibility with Compaq Fortran e TBK_FULL_SRC_FILE_SPEC This variable displays complete file name information for traceback output including the path By default the traceback output displays only the file name and extension in the source file field You must set this variable to display more The variable FOR_FULL_SRC_FILE_SPEC is also recognized for compatibility with Compagq Fortran e TMP TMPDIR and TEMP Specifies an alternate working directory where temporary files are created See Temporary Files Created by the Compiler or Linker Key IA 32 Compiler Files Summary 235 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications The following table shows files that are installed for use by the IA 32 compiler in opt inte
70. occurs program execution continues with info and warning the results might be incorrect with error and program execution stops unless a recovery method is specified with severe In the last case to prevent program termination you must include either an appropriate I O error handling specifier and recompile or for certain errors change the default action of a signal before you run the program again The first column lists error numbers returned to IOSTAT variables when an UO error is detected The first line of the second column provides the message as it is displayed following forrt1 including the severity level message number and the message text The following lines of the second column contain the status condition symbol such as FOR IOS_INCRECTYP and an explanation of the message Number Severity Level Number and Message Text Condition Symbol and Explanation None info Fortran error message number is nnn The Intel Fortran message catalog file was not found on this system See Message Catalog File Location This error has no condition symbol 241 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications None warning Could not open message catalog for_msg cat The Intel Fortran message catalog file was not found on this system See Message Catalog File Location This error has no condition symbol None info Check environment variable NLSPATH and protection of pathna
71. option is not specifed the file extension determines the format e Files with an extension of 90 F90 or i90 are free format source files e Files with an extension of for FOR ftn or i are fixed format files 59 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications openmp or openmp_ stubs Default Off disabled Specifies that OpenMP directives should be processed Options are e openmp Generate parallel code If you use this option multithreaded libraries are used but Top is not automatically invoked When openmp is specified the auto option is also set e openmp_stubs Generate sequential code The OpenMP directives are ignored and a stub OpenMP library is linked no pad_source Default nopad_source Specifies that fixed form source lines shorter than the statement field width are to be padded with spaces to the end of the statement field This affects the interpretation of character and Hollerith literals that are continued across source records The default value nopad_source causes a warning message to be displayed if a character or Hollerith literal that ends before the statement field ends is continued onto the next source record To suppress this warning message specify the warn nousage option Specifying pad_source can prevent warning messages associated with warn usage Libraries Options The libraries options let you specify libraries for y
72. programming accessing data e 191 adjusting calling conventions ENEE Ecg 182 adjusting naming conventions OVEIVIOW eege Seege ei 186 ATTRIBUTES properties 183 C C naming conventions 187 calling conventions 183 calling subprograms from the main progra EE 180 complex data types 00 200 exchanging data 191 handling data types in 198 logical data types 00000nnn 200 numeric data types ssenn 200 OVEIVICW eeeeeeescceeeeeeeeeeeeteees 179 passing arguments in 192 procedure names 188 reconciling case of names 189 summary Of Iesues 180 using common external data 194 USING modules Im 214 mixed language programs debugging E 107 module compiling programs with 17 using in mixed language programming ccceeeeeeeeees 214 module mod files multi directory 2 00 17 searching for wees ee ees ese 20 USING EE 17 module compiler option 82 module variable sssssneeeeeeeeeeee 99 mp1 compiler optton 55 multi byte character 8 multiple files 281 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications compiling and linking 16 N name case reconciling sce kasi ies oe i 189 namelist I O statement 139 names compiler option 54 naming convention adjusting in mixed language programming 186 namin
73. s3 use ml 18 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications end subroutine The makefile to compile the above code looks like this ml mod testl o testl o ifort c test1 f90 test2 o ml mod ifort c test2 90 test3 o ml mod ifort c test3 f 90 Searching for Include and mod Files Include files are brought into a program with the include preprocessor directive or a Fortran INCLUDE statement Directories are searched for include files in this order Directory of the source file that contains the include Directories specified by the Idir options Current working directory Directories specified with the FPATH environment variable eS The locations of directories to be searched are known as the include file path More than one directory can be specified in the include file path A module mod file is specified in a program by a USE statement Module files can be located in multiple directories Directories are searched for mod files in this order Directory of the source file that contains the USE statement Directories specified by the module path option Directories specified by the Idir option Current working directory Directories specified with the FPATH environment variable Ole Ge ho Specifying and Removing an Include File Path You can use the Idir option to indicate the location of include files and module files 19 Intel F
74. severe 257 Formatted I O to unit open for unformatted transfers FOR IOS_FMTIO_UNF Attempted formatted I O such as list directed or namelist I O to a unit where the OPEN 257 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications statement indicated the file was unformatted FORM specifier Check that the correct unit file was specified If the FORM specifier was not present in the OPEN statement and the file contains formatted data specify FORM FORMATTED in the OPEN statement Otherwise if appropriate use unformatted I O 264severe 264 operation requires file to be on disk or tape FOR IOS_OPERREQDIS Attempted to use a BACKSPACE statement on such devices as a terminal or pipe 965 severe 265 operation requires sequential file organization and access FOR IOS_OPEREQSEQ Attempted to use a BACKSPACE statement on a file whose organization was not sequential or whose access was not sequential A BACKSPACE statement can only be used for sequential files opened for sequential access 266 error 266 Fortran abort routine called FOR IOS_PROABOUSE The program called abort to terminate the program 268 severe 268 End of record during read FOR IOS_ENDRECDUR An end of record condition was encountered during execution of a nonadvancing I O READ statement that did not specify the EOR branch specifier 297 info 297 nn floating invalid traps
75. should be set by default See also warn no declarations V Default Off Specifies that driver tool commands should be shown and executed See also dryrun V Default None Displays the compiler version information what Default Off Prints the version strings of the Fortran command and the compiler WI option1 option2 Default Off Passes options specified by opt ion1 option2 and so forth to the linker for processing 68 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications X Default Off Alternate syntax nostdinc Removes standard directories from the include file search This option prevents the compiler from searching the default path specified by the FPATH environment variable Xlinker value Default Off Passes value directly to the linker for processing Optimization Options The optimization options let you specify how to optimize your applications for speed particular processors code size and so forth For more information about optimization see Compiler Optimizations Overview and related sections in the nte Fortran User s Guide for Linux Volume II Optimizing Applications See also Floating Point Options Descriptions of Optimization Options assume no buffered_io Default assume nobuffered_io buffer is flushed as each record is written Specifies whether records are written flushed to disk as each is written or are
76. string is pushed by value on the stack immediately after the address of the beginning of the string For certain string arguments e No Len applies when nomixed_str_len_arg is set The length of the string is not available to the called procedure This is the default e Len Mixed applies when mixed_str_len_arg is set The length of the string is pushed by value on the stack immediately after the address of the beginning of the string For string arguments the length of the string is not available to the called procedure For string arguments the first character is converted to INTEGER 4 as in ICHAR string 1 1 and pushed on the stack by value Produces a compiler error On IA 32 systems the 4 byte address of the array descriptor On Itanium based systems the 8 byte address of the array descriptor On IA 32 systems derived type arguments specified by value are passed as follows Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications e Arguments from 1 to 4 bytes are passed by value e Arguments from 5 to 8 bytes are passed by value in two registers two arguments e Arguments more than 8 bytes provide value semantics by passing a temporary storage address by reference The following table shows another Fortran ATTRIBUTES property that matches another language calling convention Other Language Calling Convention Matching ATTRIBUTES Property C C cdecl default C The
77. techniques you can use to reconcile differences between Fortran and other languages Adjusting calling conventions adjusting naming conventions and writing interface procedures are discussed in the next sections e Adjusting Calling Conventions in Mixed Language Programming e Adjusting Naming Conventions in Mixed Language Programming e Prototyping a Procedure in Fortran After establishing a consistent interface between mixed language procedures you then need to reconcile any differences in the treatment of individual data types strings arrays and so on This is discussed in Exchanging and Accessing Data in Mixed Language Programming Note This section uses the term routine in a generic way to refer to functions subroutines and procedures from different languages Adjusting Calling Conventions in Mixed Language Programming 180 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Adjusting Calling Conventions in Mixed Language Programming Overview The calling convention determines how a program makes a call to a routine how the arguments are passed and how the routines are named See Adjusting Naming Conventions in Mixed Language Programming In a single language program calling conventions are nearly always correct because there is one default for all routines and because header files or Fortran module files with interface blocks enforce consistency between the caller and
78. temporary files See Temporary Files Created by the Compiler or Linker Run Time Environment Variables The Intel Fortran run time system recognizes several environment variables These variables can be used to customize run time diagnostic error reporting for example The run time environment variables are e decfort_dump_flag If this variable is set to Y or y a core dump will be taken when any severe Intel Fortran run time error occurs e F_UFMTENDIAN This variable specifies the numbers of the units to be used for little endian to big endian conversion purposes See Environment Variable F_UFMTENDIAN Method e FOR_ACCEPT The ACCEPT statement does not include an explicit logical unit number Instead it uses an implicit internal logical unit number and the FOR_ACCEPT environment variable If FOR_ACCEPT is not defined the code accEPT f iolist reads from stdin standard input If FOR_ACCEPT is defined as a file name optionally containing a path the specified file would be read e FOR_DIAGNOSTIC_LOG_FILE If this variable is set to the name of a file diagnostic output is written to the specified file The Fortran run time system attempts to open that file append output and write the error information ASCII text to the file The setting of FOR_DIAGNOSTIC_LOG_F ILE is independent of FOR_DISABLE_DIAGNOSTIC_DISPLAY so you can disable the screen display of information but still capture the error information in a fi
79. that could not be deallocated ina DEALLOCATE statement Only whole arrays previous allocated with an ALLOCATE statement can be validly passed to DEALLOCATE 174 severe 174 SIGSEGV message text FOR IOS_SIGSEGV One of two possible messages occurs for this error number e severe 174 SIGSEGV segmentation fault occurred This message indicates that the program attempted an invalid memory reference Check the program for possible errors e severe 174 SIGSEGV possible program stack overflow occurred The following explanatory text also appears Program requirements exceed current stacksize resource limit 175 severe 175 DATE argument to DATE_AND_TIME is 256 too short LEN n required LEN 8 FOR IOS_SHORTDATEARG The number of characters associated with the DATE argument to the DATE_AND_TIME intrinsic was shorter than the required length You must increase the number of characters passed in for this argument to be at least 8 characters in length Verify that the TIME and ZONE arguments also meet their minimum lengths Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications 176 severe 176 TIME argument to DATE_AND_TIME is too short LEN n required LEN 10 FOR IOS_SHORTTIMEARG The number of characters associated with the TIME argument to the DATE_AND_TIME intrinsic was shorter than the required length You must inc
80. the assume buffered_io compiler option e FORT_CONVERTn Lets you specify the data format for an unformatted file associated with a 234 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications particular unit number n See Methods of Specifying the Data Format Overview and Environment Variable FORT _CONVERTn Method e FORT_CONVERT ext and FORT_CONVERT_ext Lets you specify the data format for unformatted files with a particular file extension suffix ext See Methods of Specifying the Data Format Overview and Environment Variable FORT _CONVERT ext or FORT_CONVERT_ext Method e FORTn Lets you specify the file name for a particular unit number n when a file name is not specified in the OPEN statement or an implicit OPEN is used and the compiler option fpscomp filesfromcmd was not specified Preconnected files attached to units 0 5 and 6 are by default associated with system standard I O files e NLSPATH The path for the Intel Fortran run time error message catalog e TBK_ENABLE_VERBOSE_STACK_TRACE This variable displays more detailed call stack information in the event of an error The default brief output is usually sufficient to determine where an error occurred Brief output includes up to twenty stack frames reported one line per stack frame For each frame the image name containing the PC routine name line
81. the record might be transferred unlike advancing I O where one entire record or records are always transferred 160 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications You can alternate between advancing and nonadvancing UO by specifying different values for the ADVANCE specifier YES and NO in the READ and WRITE record I O statements When reading records with either advancing or nonadvancing I O you can use the END specifier to branch to a specified label when the end of the file is read Because nonadvancing I O might not read an entire record it also supports an EOR specifier to branch to a specified label when the end of the record is read If you omit the EOR and the IOSTAT specifiers when using nonadvancing I O an error results when the end of record is read When using nonadvancing input you can use the SIZE specifier to return the number of characters read For example in the following READ statement SIZE X where variable X is an integer returns the number of characters read in X and an end of record condition causes a branch to label 700 150 FORMAT F10 2 F10 2 I6 READ UNIT 20 FMT 150 SIZE X ADVANCE NO EOR 700 A F 1 Record Transfer I O statements transfer all data as records The amount of data that a record can contain depends on the following circumstances e With formatted I O except for fixed length records the number of ite
82. thread basis System Drive or Directory Control and Inquiry Routines You can retrieve information about devices directories and files with these routines Standard Fortran 90 provides the INQUIRE statement which returns detailed file information either by file name or unit number Use INQUIRE as an equivalent to FSTAT LSTAT or STAT LSTAT and STAT return the same information STAT is the preferred function Additional Routines You can also use portability routines for program call and control Keyboards and speakers file management arrays floating point inquiry and control IEEE functionality and other miscellaneous uses See the table of Portability Routines in the Overview chapter of the nte Fortran Libraries Reference Math Libraries 231 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications libimf a is the math library provided by Intel and 1ibm a is the math library provided with gcc Both of these libraries are linked in by default on IA 32 and Itanium based compilers Both libraries are linked in because there are math functions supported by the GNU math library that are not in the Intel math library This linking arrangement allows the GNU users to have all functions available when using ifort with Intel optimized versions available when supported libimf a is linked in before 1ibm a If you link in 1ibm a first it will change the versions of the math functions that
83. to store temporary files Building Applications Building Applications Overview See these topics about Intel Fortran Controlling the Compilation Process Setting and Viewing Environment Variables Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Compile Time Environment Variables Running the Shell Script to Set Up the Environment Variables Invoking the Intel Fortran Compiler Examples of the ifort Command Using Module mod Files Searching for Include and mod Files Configuration Files and Response Files Specifying Alternative Tool Locations and Options Predefined Preprocessor Symbols Redirecting Command Line Output to Files Creating Running and Debugging an Executable Program Creating Shared Libraries Allocating Common Blocks Controlling the Compilation Process To customize the environment used during compilation you can specify variables options and files as follows e Environment variables to specify paths where the compiler searches for special files such as libraries and include files e Configuration files to specify the options used for every compilation and response files to specify the options and files used for individual projects Setting and Viewing Environment Variables You can use the SET command to view or set environment variables one ata time You can also set environment variables by using the ifortvars csh and ifortvars sh files to set several at
84. to stop execution at these points and look at the contents of program variables to see if they contain the correct values Points at which the debugger stops program execution are called breakpoints To set a breakpoint use one of the forms of the stop or stopi commands Using a sample program the following debugger commands set a breakpoint at line 4 run the program continue the program delete the breakpoint rerun the program and return to the shell idb stop at 4 89 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications 1 stop at squares f90 4 idb run 1 stopped at squares 4 0x120001880 gt 4 OPEN UNIT 8 FILE datafile dat STATUS OLD idb cont N Process has exited with status 0 idb delete 1 idb rerun Process has exited with status 0 idb quit o oO In this example e The stop at 4 command sets a breakpoint at line 4 To set a breakpoint at the start of a subprogram such as calc use the stop in command such aS stop in calc e The run command begins program execution and stops at the first breakpoint The program is now active allowing you to view the values of variables with print commands and perform related functions e The cont command resumes continues program execution In addition to the cont command you can also use the step next run Of rerun commands to resume execution e The delete 1
85. using a record type other than the one used to create the file are indeterminate An I O record is a collection of fields data items that are logically related and are usually processed as a unit Unless you specify nonadvancing I O ADVANCE specifier each Intel Fortran I O statement transfers at least one record Record Overhead Record overhead refers to bytes associated with each record that are used internally by the file system and are not available when a record is read or written Knowing the record overhead helps when estimating the storage requirements for an application Although the overhead bytes exist on the storage media do not include them when specifying the record length with the RECL specifier in an OPEN statement The various record types each require a different number of bytes for record overhead as described in the table below Record File Record Overhead Type Organization Fixed length Sequential None Fixed length Relative None if the vms option was omitted the default One byte if the vms option was specified Variable Sequential Eight bytes per record length Segmented Sequential Four bytes per record One additional padding byte space is added if the specified record size is an odd number Stream Sequential None required Stream_CR_ Sequential One byte per record Stream_LF Sequential One byte per record Record Length 145 Intel
86. 0 abort on other IEEE exceptions 55 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications e fpe3 specifies produce NaN signed infinities and denormal results On IA 32 systems using fpe0 will slow run time performance Many programs do not need to handle denormalized numbers or other exceptional values On Itanium based systems using fpe3 will slow run time performance fpstkchk IA 32 systems only Default Off Generates extra code after every function call to ensure that the floating point FP stack is in the expected state By default there is no checking So when the FP stack overflows a NaN value is put into FP calculations and the program s results differ Unfortunately the overflow point can be far away from the point of the actual bug The fpstkchk option places code that would access violate immediately after an incorrect call occurred thus making it easier to locate these issues fr32 Itanium based systems only Default Off Specifies that the use of high floating point registers should be disabled ftz Default Off f t z on IA 32 systems off ft z on Itanium based systems except for optimization level 03 in which case the default is on ftz Enables flush denormal results to zero This option has effect only when compiling the main program IPF_flt_eval_method0 Itanium based systems only Default Off Directs the compiler t
87. 1 Passing Integer Pointers EE 201 Receiving Pointers EE 202 Handling Arrays and Fortran Array Descriptors ecceeeeeeeeeeeeeeeeeeeeeeeeeees 203 Intel Fortran Array Descriptor Fommat 205 Handling Character Strings cccccceeeesseseeeeeeeeeeeeeeeeeeeeeeeeeeeeeenseaeeeeeeeeeeeeeenee 207 Returning Character Data Ty pes asia ois arsenal ainaian 210 Handling User Defined Types cceeeeeeeeeeeeeeeeeeeeeeeeeecaeeeeeeeeeeeseneeeeeeeeeeeneee 211 Intel Fortran C Mixed Language Proorams 211 Intel Fortran C Mixed Language Programs OvervieW essssssssssserrenreeesesrenee 212 Compiling and Linking Intel Fortran C Program 212 Using Modules in Fortran C Mixed Language Programming ssssssssssenneeeess 212 Calling C Procedures from an Intel Fortran Program 214 Dees SEENEN SE 214 Passing Arguments Between Fortran and C Procedures 0000000000000000000 215 On e Ei Tele WEE 215 Error e Eil te ke VE 215 XX Table Of Contents Run Time Library Default Error Processing sssssssssseereeeesserrrrrnrrrensserrrrrnn 215 Run Time Message Fort tege e ee Re A a ee eke 217 Message Catalog File Location 218 Values Returned to the Shell at Program Termination sssssssnneneeeeeeeeeeeee 219 Forcing a Core Dump for Severe Error 219 Handling Run Time e 220 Using the END EOR and ERR Branch Specifiers eseeeeeeeeeeeees 220 Using EVT MR MET 222 Signal Handling EE 223 Over
88. 142 output redirecting EE 27 output file renaming EE 16 output ia UE 10 output files options ee 82 output item list IEEIEUENCENE RER 155 output record transfer 162 overriding default run time library exception W 226 overriding OPTIONS 2 2eeeeeeeeeeeees 35 overview building applications 12 compiler option 34 converting unformatted data 123 data representation 109 debugging ccceeeeeeeeeeeeeeeees 88 error handling eeeees 216 files and file characteristics 141 Fortran UO 136 284 getting starte 4 handling data types in mixed language programming 198 integer data representations 112 methods of specifying the data mixed language programming adjusting calling conventions 182 adjusting naming conventions Pa es ee ON e aes 186 mixed language programming 179 native IEEE floating point representation ee 115 of Fortran C mixed language Wieeiel CIE 213 portability Wbram 229 record operations 0006 157 using libraries Eggs 227 P p optimization compiler option 71 p32 assembler option 7 PACK compiler directive 36 pad compiler option 64 Da source compiler option 60 D r report compiler option 42 par_threshold compiler option 71 parallel compiler option paralleliZer en p
89. 17549435E 38 normalized to 3 40282347E38 The IEEE denormalized subnormal limit is 1 40129846E 45 The precision is approximately one part in 2 23 typically 7 decimal digits REAL KIND 8 DOUBLE PRECISION Representation REAL 8 same as REAL KIND 8 data occupies 8 contiguous bytes stored in IEEE T_floating format Bits are labeled from the right 0 through 63 as shown below 63 62 a2 il a EXPONENT FRACTION A H ZK SHE GE The form of REAL 8 data is sign magnitude with bit 63 the sign bit 0 for positive numbers 1 for negative numbers bits 62 52 a binary exponent in excess 1023 notation and bits 51 0 a normalized 53 bit fraction including the redundant most significant fraction bit not represented The value of data is in the approximate range 2 2250738585072013D 308 normalized to 1 7976931348623158D308 The IEEE denormalized subnormal limit is 4 94065645841246544D 324 The precision is approximately one part in 2 52 typically 15 decimal digits REAL KIND 16 EXTENDED PRECISION Representation REAL 16 same as REAL KIND 16 data occupies 16 contiguous bytes stored in IEEE style X_floating format Bits are labeled from the right 0 through 127 as shown below 12 128 12 au d EXPONENT FRAGTION A Lef TE TMPSA GE The form of REAL 16 data is sign magnitude with bit 127 the sign bit 0 for positive numbers 1 for negative numbers bits 126 112 a binary exponent in 115 Intel Fortran
90. 3 Check for an environment variable F_UFMTENDIAN for the specified unit number or for all units 4 Check the OPEN statement CONVERT qualifier 126 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications 5 Check whether an OPTIONS statement with a CONVERT keyword qualifier was present when the program was compiled 6 Check whether the compiler option convert keyword was present when the program was compiled Environment Variable FORT CONVERTn Method You can use this method to specify a non native numeric format for each specified unit number You specify the numeric format at run time by setting the appropriate environment variable before an implicit or explicit OPEN to that unit number When the appropriate environment variable is set when you open the file the environment variable is always used because this method takes precedence over the other methods For instance you might use this method to specify that a unit number will use a particular format instead of the format specified in the program perhaps for a one time file conversion For example assume you have a previously compiled program that reads numeric data from unit 28 and writes it to unit 29 using unformatted I O statements You want the program to read nonnative big endian IEEE floating point format from unit 28 and write that data in native little endian format to unit 29 In this case the data is converted from b
91. 32 compiler option 38 prof_gen compiler option 71 prof_use compiler option 71 profdcg file EEN 238 profile guided optimization 5 profmerge fie 237 238 proforder file 237 238 program creating running and debugging DEE 27 prototyping a procedure 190 Q Qinstall compiler option 82 Qlocation compiler option 23 82 Qoption compiler option 23 82 R r compiler Option ceeeeee 47 RANDOM_NUMBER intrinsic subroutine 230 286 RANDOM _ SEED intrinsic subroutine EE 230 rcd compiler option 64 READ statement ADVANCE specifier 00 161 READ statement 138 139 147 158 READONLY specifier in OPEN Statement 160 REAL compiler directive 36 REAL data representation 116 REAL KIND 16 data representation SE ee 117 REAL KIND 4 data representation Gre KeEER E DEENS gege 116 REAL KIND 8 data representation dE Ee Eet SEA 116 real_size compiler option 47 RECL specifier in OPEN statement 146 147 RECL Vales ege 142 reconciling Case Of NAMES ees 189 record BEE 158 record characteristics OPEN statement specifiers for 152 record I O advancing 255 ie ee es i 161 nonadvancing ssseeseeeeeeees 161 r cord I O EE 161 record UO statement specifiers 158 record engt 147 record lOCKING ccceeeeeeeeeees 160
92. 38 COMPLEX EE 118 data type COMPLEX 16 aannnannanononnnnanan 119 converting unformatted files 123 COMPLEX 4 KEE 118 data types COMPLEX 8 ceeeeeeeeteees 118 ene TEE 209 COMPLEX KIND 16 119 debugger equivalents 99 COMPLEX KIND 4 0 118 Fortran and CN 198 COMPLEX KIND 8 118 handling in mixed language COMPL EST 118 programming 267 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications OVEIVICW ccccecceeeeeeeeeeeees 198 aigle 110 data types eeeecceeeeeeeeeseeeeeeeeeees 99 date and time routines 230 DD compiler option 60 debugger See debugging cceee 88 debugging commands Summary OT 93 COMIMAINGS EE 91 displaying variables 99 EXpPreSS OnS ssssseesseeeeene neeese 106 getting started with 89 locating unaligned data 108 mixed language programs 107 lande EN 89 OVEIVIOW eececceeeeeeeeeeecteeeeeeeees 88 preparing program Tor 90 program that generates a signal bebe heen 108 SQUARES example program 95 decfort_dump_flag environment el 234 268 decimal Comveraions 240 DECLARE compiler directive 36 DECORATE proper 183 default file NAMES EE 149 pathnames un 149 default behavior of compiler 8 DEFAULTFILE specifier in OPEN statement 147 149
93. 6E 45 are denormalized subnormal COMPLEX 8 DOUBLE COMPLEX Double precision complex floating point values in a pair of IEEE T_floating format parts real and imaginary The real and imaginary parts each range from 2 2250738585072013D 308 to 1 7976931348623158D308 Values between 2 2250738585072008D 308 and 4 94065645841246544D 324 are denormalized subnormal 16 bytes 128 bits COMPLEX 16 EXTENDED PRECISION 32 bytes 256 bits Extended precision complex floating point values in a pair of IEEE style X_floating format parts real and imaginary The real and imaginary parts each range from 6 4751751194380251 109244389582276465524996Q 4966 to 1 189731 495357231 765085759326628007016196477Q4932 LOGICAL See LOGICAL 2 LOGICAL 4 and LOGICAL 8 Logical value either LOGICAL 2 LOGICAL 4 or LOGICAL 8 The size is controlled by the integer_size nn compiler option The default is integer_size 32 LOGICAL 4 109 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications LOGICAL 1 1 byte Logical values TRUE or FALSE 8 bits LOGICAL 2 2 bytes Logical values TRUE or FALSE 16 bits LOGICAL 4 4 bytes Logical values TRUE or FALSE 32 bits LOGICAL 8 8 bytes Logical values TRUE or FALSE 64 bits CHARACTER 1 byte 8 Character data represented by character code convention bits per Character declarations can
94. 7 contains the size of a single element of the array e The third longword bytes 8 to 11 contains the offset The offset is added to the base address to define the start of the array e The fourth longword bytes 12 to 15 contains the low order bit set if the array has been defined storage allocated Other bits may also be set by the compiler within this longword for example to indicate a contiguous array e The fifth longword bytes 16 to 19 contains the number of dimensions rank of the array e The sixth longword bytes 20 to 23 is reserved e The remaining longwords bytes 24 up to 107 contain information about each dimension up to seven Each dimension is described by three additional longwords o The number of elements extent o The distance between the starting address of two successive elements in this dimension in bytes o The lower bound An array of rank one requires three additional longwords for a total of nine longwords 6 3 1 and ends at byte 35 An array of rank seven is described in a total of 27 longwords 6 3 7 and ends at byte 107 For example consider the following declaration integer target a 10 10 integer pointer p p cad E SEET call f p 206 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications The descriptor for actual argument p would contain the following values The first longword bytes 0 to 3 contain the base address a
95. 9 FIXEDFORMLINESIZE compiler el 36 fixed length record type 144 146 fixed length recorde 170 floating point options ssonnnnena 55 floating point representations 119 fltconsistency compiler option 55 271 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications fnsplit compiler option 71 FOR IOS_ARRSIZEOVF error MESSAGE inaran aai 242 FOR IOS_ASSERTERR error WU E 242 FOR IOS_ATTACCNON error MESSAGE asks aitan 242 FOR IOS_BACERR error message Reeg 242 FOR IOS_BRK_RANGE error VSS SAS diiirn aan ai 242 FOR IOS_ BRK_RANGE2 error WU Le E 242 FOR IOS_BUG_CHECK error MGSSAG Git tic canker ain 242 FOR IOS_CANSTAFIL error MESSAQE niisiis ennenen 242 FOR IOS_CAOVEEXI error WAS EE 242 FOR IOS_CLOERR error message d se A trois 242 FOR IOS_DELERR error message EE 242 FOR IOS_DIV error message 242 FOR IOS_DUPFILSPE error MESSAGE isecicicivccscctocstvastccnenss 242 FOR IOS_ENDDURREA error WE 242 FOR IOS_ENDFILERR error e EE 242 272 FOR IOS_ENDRECDUR error e EN 242 FOR IOS_ERRDURREA error MESSAGE cccceceeeeereneseeeeeeeeees 242 FOR IOS_ERRDURWRI error MOSSE GE 242 FOR IOS_FILNAMSPE error MESSAGE 2 ccceccceeeeseeceesenseenes 242 FOR IOS_FILNOTFOU error e E 242 FOR IOS_FINERR error message ER 242 FOR IOS_FLOCONFAI error e GE 242 FOR IOS_FLODIVOEXC error e hasiecciccsetcvecesndceatannan s 242 FOR IOS_FL
96. ALIAS property can be used with any other Fortran calling convention property to preserve mixed case names You can also use the DECORATE property in combination with the ALIAS property to specify that the external name specified in ALIAS should have the correct prefix and postfix decorations for the calling mechanism in effect Adjusting Naming Conventions in Mixed Language Programming Adjusting Naming Conventions in Mixed Language Programming Overview The ATTRIBUTES option C determines naming conventions as well as calling conventions Calling conventions specify how arguments are moved and stored naming conventions specify how symbol names are altered when placed in a o file Names are an issue for external data symbols shared among parts of the same program as well as among external routines Symbol names such as the name of a subroutine identify a memory location that must be consistent among all calling routines Parameter names names given in a procedure definition to variables that are passed to it are never affected Names are altered because of case sensitivity in C lack of case sensitivity in Fortran name decoration in C or other issues If naming conventions are 185 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications not reconciled the program cannot successfully link and you will receive an unresolved external error See these topics C C Naming Conven
97. Arithmetic Options for Itanium Based Systems in Volume II Optimizing Applications mp1 Default Off Restricts floating point precision to be closer to declared precision This option has some impact on speed but less than the impact of mp 57 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications pc 32 64 80 IA 32 systems only Default pc64 Enables floating point significand precision control Possible values are e pc32 Sets internal FPU precision to 24 bit significand e pc64 Sets internal FPU precision to 53 bit significand e pc8s0 Sets internal FPU precision to 64 bit significand Biel m I treats The language options let you specify semantics syntax and source file format See Also Compatibility Options Data Options Descriptions of Language Options no Jaltparam Default altparam alternate syntax is allowed Alternate syntax no dps Allows alternate syntax without parentheses for PARAMETER statements The alternate syntax for PARAMETER statements is PARAMETER parl expl par2 exp2 This form does not have parentheses around the assignment of the constant to the parameter name With this form the type of the parameter is determined by the type of the expression being assigned to it and not by any implicit typing no d_lines Default nod_lines Alternate syntax DD 58 Intel Fortran Compiler for Linux Systems User s Guide Volume l
98. BACKSPACE statement 138 158 bash_profile siccerereccascua care tesuecsec 14 bash_profile nie 14 big endian storage eeeeeese 123 BIG_ENDIAN keyword 123 binary conversions 000 0 240 breakpoints SERA eiert 91 breakoomte AE 91 building applications IVESIC at 12 by reference argument passing 192 by value argument passing 192 Cc c output files compiler option 82 C property 0 0 0 0 eee 183 189 C run time compiler option 86 C source files e eil lte EE 16 C structures using in mixed language programming ccceeeeeeeees 194 C variables using in mixed language programming cceeeeeeeeees 194 C C naming conventions 187 C Fortran mixed language programs calling C procedures 216 COMPING E 213 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications linking WEE 213 naming conventions 216 OVEIVIOW eecccceeeeeeeeeeeeeeeeeeees 213 passing arguments 216 calling C procedures from a Fortran program 216 calling convention description of 179 calling conventions and ATTRIBUTES properties 183 and mixed language programming E AEE ETT 183 calling subprograms from main program E 180 carriage control ccdefault compiler option 64 CB compiler option 86 ccdefault compiler optio
99. C routine Example of Returning Complex Data Types from C to Fortran Fortran code COMPLEX BAT WBAT REAL X Y BAT WBAT X Y Corresponding C routine struct _mycomplex float real imag typedef struct _mycomplex _single_complex void WBAT _single_complex location float x float y float realpart float imaginarypart program text producing realpart and imaginarypart location real realpart location imag imaginarypart In the above example the following restrictions and behaviors apply e The argument location does not appear in the Fortran call it is added by the compiler e The C subroutine must copy the result s real and imaginary parts correctly into location e The called procedure is type void If the function returned a DOUBLE COMPLEX value the type float would be replaced by the type double in the definition of Location in WBAT Handling Fortran Array Pointers and Allocatable Arrays 200 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications How Fortran 95 90 array pointers and arrays are passed is affected by the ATTRIBUTES properties in effect and by the INTERFACE if any of the procedure they are passed to If the INTERFACE declares the array pointer or array with deferred shape for example ARRAY its descriptor is passed This is true for array pointers and all arrays not just allocatable arrays If the INTERFA
100. CE declares the array pointer or array with fixed shape or if there is no interface the array pointer or array is passed by base address as a contiguous array which is like passing the first element of an array for contiguous array slices When a Fortran 95 90 array pointer or array is passed to another language either its descriptor or its base address can be passed The following shows how allocatable arrays and Fortran 95 90 array pointers are passed with different attributes in effect e If the property of the array pointer or array is not included or is REFERENCE it is passed by descriptor regardless of the property of the passing procedure None C or C REFERENCE e If the property of the array pointer or array is VALUE an error is returned regardless of the property of the passing procedure Note that the VALUE option cannot be used with descriptor based arrays When you pass a Fortran array pointer or an array by descriptor to a non Fortran routine that routine needs to know how to interpret the descriptor Part of the descriptor is a pointer to address space as a C pointer and part of itis a description of the pointer or array properties such as its rank stride and bounds For information about the Intel Fortran array descriptor format see Handling Arrays and Fortran Array Descriptors Fortran 95 90 pointers that point to scalar data contain the address of the data and are not passed by descriptor Handling Int
101. CR or Stream_LF record is a variable length record whose length is indicated by explicit record terminators embedded in the data not by a count These terminators are automatically added when you write records to a stream type file and are removed when you read records Each variety uses a different 1 byte record terminator 172 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications e Stream_CR files use only a carriage return as the terminator so Stream_CR files must not contain embedded carriage return characters e Stream_LF files use only a line feed new line as the terminator so Stream_LF files must not contain embedded line feed new line characters This is the usual operating system text file record type The figure below shows the layout of Stream_CR and Stream_LF records Pw Pp Record length RECL value 1 2K 9825 GE Microsoft Fortran PowerStation Compatible Files When using the fpscomp options for Microsoft Fortran PowerStation compatibility the following types of files are possible e Formatted Sequential e Formatted Direct e Unformatted Sequential e Unformatted Direct Formatted Sequential Files A formatted sequential file is a series of formatted records written sequentially and read in the order in which they appear in the file Records can vary in length and can be empty They are separated by carriage return OD and line feed 0A
102. Compiler directives cccccccccee 36 compiler limits eeeeeeeeees 238 Index compiler option convert method 135 compiler options compatibility 0 2 eeeeeeeeeetteeeeeeees 38 compilation diagnoOstics 42 et EE 47 e 35 external procedures 54 getting bein 35 language e sees eeeeeeeeeeeeeees 60 LIESE ee 62 miscellaneous sseneeeeeeenneee 64 optimization BE 71 output UE 82 OVvervleu 0 eeeccccceeeeeeeeeeeneeeeeeeeeees 34 PUTING ee 86 Styles E 35 compiler Options seeeeeeeees 55 compile time environment variables EE eeh 234 compiling C Fortran mixed language program E 213 COMPLEX data representation 118 complex data types 265 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Ate 16 le EE 200 complex variable seseneeeeeeenn 99 COMPLEX 16 data representation P E ee 119 COMPLEX 4 data representation E 118 COMPLEX 8 data representation Ra ne EE 118 COMPLEX KIND 16 data representation sseeeeeeeeeeene 119 COMPLEX KIND 4 data representation ccceeeeee 118 COMPLEX KIND 8 data representation cceee 118 COMPLEX 16 data representation E eet heen 118 COMPLEX 32 data representation ENEE 119 COMPLEX 8 data representation118 complex_limited_range compiler OPUN EE 71 components of compiler 2 config
103. Compiler for Linux Systems User s Guide Volume Building Applications ccdefault keyword Default ccdefault default Specifies the type of carriage control used for units 6 and The choices for keyword are e default Specifies that the compiler is to use the default carriage control setting This choice can be affected by the vms option If vms ccdefault default is specified carriage control defaults to fortran if the file is formatted and the unit is connected to a terminal If novms ccdefault default is specified carriage control defaults to list e fortran Specifies normal Fortran interpretation of the first character e list Specifies one line feed between records e none Specifies no carriage control processing dryrun Default Off Specifies that driver tool commands should be shown but not executed See also SN u dynamic linkerfile Default Off Specifies a dynamic linker file instead of the default fpic or fPIC Default Off Specifies that position independent code should be generated Specifies full symbol preemption Global symbol definitions as well as global symbol references get default that is preemptable visibility unless explicitly specified otherwise See also Creating Shared Libraries fvisibility keyword and fvisibility keyword file 64 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Specifies the default visibility for global symbols
104. Compiler for Linux Systems User s Guide Volume Building Applications excess 16383 notation and bits 111 0 a normalized 113 bit fraction including the redundant most significant fraction bit not represented The value of data is in the approximate range 6 4751751 194380251 109244389582276465524996Q 4966 to 1 189731 495357231 765085759326628007016196477Q4932 Unlike other floating point formats there is little if any performance penalty from using denormalized extended precision numbers This is because accessing denormalized REAL KIND 16 numbers does not result in an arithmetic trap the extended precision format is emulated in software The smallest normalized number is 3 3621031431 1209350626267781 7321 753Q 4932 The precision is approximately one part in 2 112 or typically 33 decimal digits COMPLEX KIND 4 COMPLEX Representation COMPLEX 4 same as COMPLEX KIND 4 and COMPLEX 8 data is 8 contiguous bytes containing a pair of REAL 4 values stored in IEEE S_floating format The low order 4 bytes contain REAL 4 data that represents the real part of the complex number The high order 4 bytes contain REAL 4 data that represents the imaginary part of the complex number as shown below a1 30 23 ee o REAL Gett EXPONENT FRACTION IMAGINARY BHT EXPONENT FRACTION tated Choe 3E The limits and underflow characteristics for REAL 4 apply to the two separate real and imaginary parts of a COMPLEX 4 number Like
105. DEFINE compiler directive 36 DEFINE FILE statement 138 DELETE statement 138 158 denormalized numbers 119 derived type variable n0nnnnnnn 99 differences between versions 240 direct access fOr recordS cecceececeeceeeeeeeeees 158 dreckeg 36 disclaimer 02 cece eeceeeececceeeceeeeeeeees 1 displaying variables in debugging EE 99 documentation additional 0 ecceeeeeeeceeceeeeeeeeee 3 documentation conventions 3 DOUBLE COMPLEX data representation n s 118 DOUBLE PRECISION data representation eeeee 116 double_size compiler option 47 dps compiler option 60 dryrun compiler option 64 dynamic common block allocating memory Io 32 guidelines for USING 32 dynamic linker compiler option 64 dyncom compiler option 32 47 E 90 compiler option 42 95 compiler option 42 ebp register ee 71 Le UE 238 Ee a 238 CICDINTNG 253 iit Avni ati cain 238 END branch specifier 222 ENDFILE statemert 138 158 environment variable F_UFMTENDIAN method 130 Index environment variable FORT _CONVERT ext method 129 environment variable FORT CONVERT ext method 129 environment variable FORT_CONVERTn nethod 128 environment variables compile time cee 234 running shell scrip
106. FLUFMTENDIAN which take precedence over the OPEN statement CONVERT keyword method OPTIONS Statement Method You can only specify one numeric file format for all unformatted file unit numbers using this method unless you also use one of the environment variable methods or OPEN statement CONVERT keyword method You specify the numeric format at compile time and must compile all routines under the same OPTIONS statement CONVERT keyword qualifier You could use one source program and compile it using different i fort commands to create multiple executable programs that each read a certain format The environment variable methods and the OPEN statement CONVERT method take precedence over this method For instance you might use the environment variable FORT _CONVERTn method or OPEN statement CONVERT method to specify each unit number that will use a format other than that specified using the ifort option method This method takes precedence over the convert keyword compiler option method You can use OPTIONS statements to specify the appropriate floating point formats in memory and in unformatted files instead of using the corresponding ifort command qualifiers For example to use VAX F_floating and G_floating as the unformatted file format specify the following OPTIONS statement 133 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications OPTIONS CONVERT VAXG Because this method affects all un
107. First character Passed bv reference 207 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications reference converted to along with length along with INTEGER 4 and length passed by value String with Error First character First character VALUE option converted to converted to INTEGER 4 and INTEGER 4 and passed by value passed by value String with Passed by Passed by Passed by reference REFERENCE reference reference no length no length option possibly along with length The important things to note about the above table are Character strings without the VALUE or REFERENCE attribute that are passed to C routines are not passed by reference Instead only the first character is passed and it is passed by value Character strings with the VALUE option passed to C routines are not passed by reference Instead only the value of the first character is passed For string arguments with default ATTRIBUTES ATTRIBUTES C or REFERENCE o When nomixed_str_len_arg Is set the length of the string is pushed by value on the stack after all of the other arguments This is the default o When mixed_str_len_arg is set the length of the string is pushed by value on the stack immediately after the address of the beginning of the string For string arguments passed by reference with default ATTRIBUTES o When nomixed_str_len_arg Is set the length of the string is not available to the called procedu
108. GER REFPARM END SUBROUTINE In C and C all arguments are passed by value except arrays which are passed by reference to the address of the first member of the array Unlike Fortran C and C do not have calling convention directives to affect the way individual arguments are passed To pass non array C data by reference you must pass a pointer to it To pass a C array by value you must declare it as a member of a structure and pass the structure The following C declaration sets up a Call to the example Fortran testproc subroutine extern void testproc int ValParm int RefParm The following table summarizes how to pass arguments by reference and value An array name in C is equated to its starting address because arrays are normally passed by reference You can assign the REFERENCE property to a procedure as well as to individual arguments Passing Arguments by Reference and Value Language ATTRIBUTE Argument To Pass by To Pass by Type Reference Value Fortran Default Scalars and Default VALUE option derived types C option Scalars and REFERENCE Default derived types option Default Arrays Default Cannot pass by value C option Arrays Default Cannot pass by value C C Non arrays Pointer Default argument_name Arrays Default Struct type array_name 192 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications This table does not describe argument passing of strings and Fo
109. Gite 138 Files and File Characteristics Overview ccccceeeeeeeeeeeeneeeeeeeeeeeeeeeeneeeeeeeees 140 e lee e E 140 Sequential Organization EEN 141 Relative Organization ege 141 Table Of Contents Internal Files and Scratch Fles EEN 141 Internal Fles cess ee ee She a Ala ls Nt tlle Nel te Me ts A eats Mo lade es 142 SEET EE e nee en ee ee ee a ee ane a ee ree ene ee eee 142 Record RR et 143 Fixed Length Record TY EE 143 Variable Length Record Tvpe ee 143 Segmented Record Type ENEE 143 Stream Record TYPO EE 144 Stream_LF and Stream_CR Record Type EEN 144 Choosing a Record Ty OCs scysz cess Tovidev es olade een aferevolelecesec ade Caveseseiisecaledepelaser Sens 144 Record OVE INCA sist ai aA ele a eee et 145 R cord Length KEE 145 Accessing and Assigning Ra 146 Assigning Files to Logical Units cceeceeeeeeeeeeeeeeeeeenneeeeeeeeeeeeeeeeneneeeeeeeees 146 Using Default Values a2 sansa ota ia eee ee 146 Supplying a File Name in an OPEN Gtatement 147 Using Environment Variables Edge ee 147 Implied Intel Fortran Logical Unit Number 147 Default Pathnames and File Names AEN 148 Examples of Applying Default Pathnames and File Names nsaesnennneeeen 149 Rules for Applying Default Pathnames and EileNames 149 Using Preconnected Standard W O FileS cceceeesceceesesseeeesesseeneeeeesseeseneeees 150 Opening Files OPEN Stee HEEN EES 150 xvi Table Of Contents OPEN Statement SpecifierS AEN 151 Spec
110. I O with any type of supported file organization and record type If you select sequential access mode for files with sequential or relative organization records are written to or read from the file starting at the beginning of the file and continuing through it one record after another A particular record can be retrieved only after all of the records preceding it have been read new records can be written only at the end of the file Direct Access Direct access transfers records selected by record number to and from either sequential files stored on disk with a fixed length record type or relative organization files If you select direct access mode you can determine the order in which records are read or written Each READ or WRITE statement must include the relative record number indicating the record to be read or written You can directly access a sequential disk file only if it contains fixed length records Because direct access uses cell numbers to find records you can enter successive READ or WRITE statements requesting records that either precede or follow previously requested records For example the first of the following statements reads record 24 the second reads record 10 REAI REAI 12 REC 24 12 REC 10 J D D Limitations of Record Access by File Organization and Record Type You can use both access modes on sequential and relative files However direct access to a sequential org
111. IOS_NO_ SUCDEV A pathname included an invalid or unknown device name when an OPEN operation was attempted 43 severe 43 File name specification error FOR IOS_FILNAMSPE A pathname or file name given to an OPEN or INQUIRE statement was not acceptable to the Intel Fortran RTL I O system 44severe 44 Inconsistent record type FOR IOS_INCRECTYP The RECORDTYPE value in an OPEN statement did not match the record type attribute of the existing file that was opened 45 severe 45 Keyword value error in OPEN statement FOR IOS_KEYVALERR An improper value was specified for an OPEN or CLOSE statement specifier requiring a value A46severe 46 Inconsistent OPEN CLOSE parameters FOR IOS_INCOPECLO Specifications in an OPEN or CLOSE statement were inconsistent Some invalid combinations follow e READONLY or ACTION READ with STATUS NEW or STATUS SCRATCH e READONLY with STATUS REPLACE ACTION WRITE or ACTION READWRITE e ACCESS APPEND with READONLY ACTION READ STATUS NEW or STATUS SCRATCH e DISPOSE SAVE PRINT or SUBMIT with STATUS SCRATCH e DISPOSE DELETE with READONLY e CLOSE statement STATUS DELETE with OPEN statement READONLY e ACCESS APPEND with STATUS REPLACE Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications e ACCESS DIRECT or KEYED with POSITION APPEND ASI
112. IOS_VFEVALERR The value of a variable format expression was not within the range acceptable for its intended use for example a field width was less than or equal to zero A value of 1 was assumed except for a P edit descriptor for which a value of zero was assumed 69 error 69 Process interrupted SIGINT FOR IOS_SIGINT The process received the signal SIGINT Determine source of this interrupt signal described in signal 3 70 severe 70 Integer overflow FOR IOS_INTOVF During an arithmetic operation an integer value exceeded byte word or longword range The result of the operation was the correct low order part Consider specifying a larger integer data size modify source program or for an INTEGER declaration possibly use the 90 option integer_size nn 71 severe 71 Integer divide by zero FOR IOS_INTDIV During an integer arithmetic operation an attempt was made to divide by zero The result of the operation was set to the dividend which is equivalent to division by 1 72 error 72 Floating overflow FOR IOS_FLTOVF During an arithmetic operation a 251 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications 252 floating point value exceeded the largest representable value for that data type 73 error 73 Floating divide by zero FOR IOS_FLTDIV During a floating point arithmetic operation an attempt was made to divide by zero 74 e
113. LENCE expression with an entity in a static common block or a DATA initialized variable Why Use a Dynamic Common Block A main reason for using dynamic common blocks is to enable you to control the common block allocation by supplying your own allocation routine To use your own allocation routine you should link it ahead of the Fortran run time library This routine must be written in the C language to generate the correct routine name The routine prototype is void _FTN_ALLOC void mem int size char name where e mem Is the location of the base pointer of the common block which must be set by the routine to point to the block of memory allocated e size is the integer number of bytes of memory that the compiler has determined are necessary to allocate for the common block as it was declared in the program You can ignore this value and use whatever value is necessary for your purpose 5 Note You must return the size in bytes of the space you allocate The library routine that calls _FTN_ALLOC ensures that all other occurrences of this 31 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications common block fit in the space you allocated Return the size in bytes of the space you allocate by modifying size e name is the name of the common block being dynamically allocated Allocating Memory to Dynamic Common Blocks The run time library routine f 90_dyncom performs memory alloc
114. Linux Systems User s Guide Volume Building Applications libimf a e 228 libimf a library 233 libimf so file E 228 libirc a E 228 libiremt a le 228 libm a SEN eseersge seg 233 libompstub a le 228 libraries creating shared 30 using OVEIVICW cceecceeeeeeeeeeeeees 227 dere TEEN 228 libraries optons 62 libsvml a file E 228 libunwind a file nl 228 libunwind so fie 228 Ibunwind so bnle eee 228 limitations numeric conversion s s s 126 limits OI ee 238 Eet ee 7 linker library 280 EEN 16 linking C Fortran mixed language programs ana 213 preventing VE 16 linux preprocessor symbol 25 list directed I O statement 139 little endian storage eee 123 LITTLE_ENDIAN keyword 123 location message catalog file 217 logical data representation 114 logical data types PVC G BE 200 logical I O umnte cece 137 logo compiler option 64 M macro See preprocessor symbol 25 make command USING E 14 EE 14 17 manuals lee tele RE 3 map ER UE 86 math libraries eeeeeeeeeeees 233 message catalog file location 217 methods of specifying the data format OVEIVICW eececccceeeeeeeeeeeeeeeeees 127 Microsoft compatibility 174 Microsoft Fortran PowerStation ell a le le EE 174 miscellaneous options 64 mixed_str_len_arg compiler option EE 54 183 209 mixed language
115. NCTION SUBROUTINE C and C function void function There are some important differences in the way languages implement routines Argument passing naming conventions and other interface issues must be thoughtfully and consistently reconciled between any two languages to prevent 179 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications program failure and indeterminate results However the advantages of mixed language programming often make the extra effort worthwhile A summary of a few mixed language advantages and restrictions follows e Fortran Assembly Language Assembly language routines are small and execute very quickly because they do not require initialization as do high level languages like Fortran and C Also they allow access to hardware instructions unavailable to the high level language user In a Fortran assembly language program compiling the main routine in Fortran gives the assembly code access to Fortran high level procedures and library functions yet allows freedom to tune the assembly language routines for maximum speed and efficiency The main program can also be an assembly language program e Fortran C or C Generally Fortran C programs are mixed to allow one to use existing code written in the other language Either Fortran or C can call the other so the main routine can be in either language This section provides an explanation of the keywords attributes and
116. NEXTREC would still return 2 e On units with CARRIAGECONTROL FORTRAN the default PUTC and FPUTC characters are treated as carriage control characters if they appear in column 1 e On sequentially formatted units the C string n c which represents the carriage return line feed escape sequence is written as CHAR 13 carriage return and CHAR 10 line feed instead of just line feed or CHAR 10 On input the sequence 13 followed by 10 is returned as just 10 The length of character string n c is 1 character whose ASCII value indicated by ICHAR n c is 10 e Reading and writing is in a raw form for direct files Separators between records can be read and overwritten Therefore be careful if you continue using the file as a direct file I O errors arising from the use of these routines result in an Intel Visual Fortran run time error Some portability file I O routines have equivalents in standard Fortran 95 90 For example you could use the ACCESS function to check a file specified by name for accessibility according to mode It tests a file for read write or execute permission as well as checking to see if the file exists It works on the file attributes as they exist on disk not as a program s OPEN statement specifies them Instead of ACCESS you can use the INQUIRE statement with the ACTION parameter to check for similar information The ACCESS function always returns 0 for read permission on FAT files meaning t
117. OINVEXC error MESSAGE aide es 242 FOR IOS_FLOOVFEXC error e CT 242 FOR IOS_ FLOUNDEXC error e GE 242 FOR IOS_FLTDIV error message FOR IOS_FLTUND error message E 242 FOR IOS_FMTIO_UNF error MT e rennen 242 FOR IOS_FMTSYN error message E 242 FOR IOS_FORVARMIS error IS e E 242 FOR IOS_INCFILORG error BEE EE 242 FOR IOS_INCOPECLO error MOSSAQC wis cessaeerncencerecennsenesenees 242 FOR IOS_INCRECLEN error MICS E 242 FOR IOS_INCRECTYP error le vin ccscccesacvecdsnscvenatnaceate 242 FOR IOS_INFFORLOO error CSSA EN 242 FOR IOS_INPCONERR error MOSSAQEC sisirin 242 FOR IOS_INPRECTOO error a e E 242 FOR IOS_INPSTAREQ error MOSSAQE TT 242 FOR IOS_INSVIRMEM error MESSAGE outlets 242 FOR IOS_INTDIV error message EE 242 FOR IOS_INTOVF error message EE Ee 242 Index FOR IOS_INVARGFOR error Wu Le EE 242 FOR IOS_INVDEALLOC error MESSAQE cccecceeeeeseneeseeeeeeeeneeees 242 FOR IOS_INVDEALLOC2 error MESSAGE E 242 FOR IOS_INVLOGUNI error CSSA E 242 FOR IOS_INVREALLOC error MESSAGE idnina piaig 242 FOR IOS_INVREFVAR error MESSAQE e 242 FOR IOS_KEYVALERR error MESSAGE E 242 FOR IOS_LISIO_SYN error MESSAJE wisccdiinstesccinaveestinswnvedes 242 FOR IOS_MIXFILACC error MESSAGE E 242 FOR IOS_NO_CURREC error We E 242 FOR IOS_NO_SUCDEV error Message E 242 FOR IOS_NOTFORSPE error MESSAGE oi cccccinarsnceivewinscxncnnnanes 242 FOR IOS_NULPTRERR error MESSAGE EE 242 FOR IOS_OPEDEFREQ error W
118. OPEN The USEROPEN function INTEGER ERRNUM CTR I 1 FORMAT I ERRNUM 0 WRITE 6 EX1 Access data using formatted I 0O WRITE 6 EX1 Open file with USEROPEN and put some data in it OPEN UNIT 1 FILE exl dat STATUS NEW USEROPEN UOPEN amp ERR 9 amp IOSTAT errnum DO CTR 1 10 WRITE 1 1 CTR END DO WRITE 6 EX1 Close and re open without USEROPEN CLOSE UNIT 1 OPEN UNIT 1 FILE exl dat STATUS OLD FORM FORMATTED amp ERR 99 amp IOSTAT errnum WRITE 6 EX1 Read and display what is in file DO CTR 1 10 READ 1 1 i WRITE 6 i END DO WRITE 6 EX1 Successful if 10 records shown CLOSE UNIT 1 STATUS DELETE 168 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications STOP 9 WRITE 6 EX1 Error on USEROPEN is errnum STOP 99 WRITE 6 EX1 Error on 2nd open is errnum END PROGRAM EX1 Format of Record Types Fixed Length Records When you specify fixed length records all records in the file contain the same number of bytes When you open a file that is to contain fixed length records you must specify the record size by using the RECL specifier A sequentially organized file opened for direct access must contain fixed length records to allow the record position in
119. OR IOS_ENDFILERR One of the following conditions occurred e The file was not a sequential organization file with variable length records e The file was not opened for sequential or append access e An unformatted file did not contain segmented records e The Intel Fortran RTL I O system detected an error during execution of an ENDFILE statement B34severe 34 Unit already open FOR IOS_UNIALROPE A DEFINE FILE statement specified a logical unit that was already opened 35 severe 35 Segmented record format error FOR IOS_SEGRECFOR An invalid segmented record control data word was detected in an unformatted 246 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications sequential file The file was probably either created with RECORDTYPE FIXED or VARIABLE in effect or was created by a program written in a language other than Fortran B86 severe 36 Attempt to access non existent record FOR IOS_ATTACCNON A direct access READ or FIND statement attempted to access beyond the end of a relative file or a sequential file on disk with fixed length records or access a record that was previously deleted in a relative file 37 severe 37 Inconsistent record length FOR IOS_INCRECLEN An attempt was made to open a direct access file without specifying a record length 38severe 38 Error during write FOR IOS_ERRDURWRI The Intel Fortran RTL I O system detected an error co
120. ORT _CONVERT ext or FORT _CONVERT_ ext environment variable is used if a FORT _CONVERTn environment variable is not set for the unit number The FORT_CONVERTn and the FORT_CONVERT ext or FORT_CONVERT_ ext environment variable methods take precedence over the other methods For instance you might use this method to specify that a unit number will use a particular format instead of the format specified in the program perhaps for a one time file conversion You can set the appropriate environment variable using the format FORT_CONVERT ext or FORT_CONVERT_ ext Consider using the FORT_CONVERT_ ext form because a dot cannot be used for environment variable names on certain Linux command shells If you do define both FORT_CONVERT ext and FORT_CONVERT_ ext for the same extension ex the file defined by FORT_CONVERT ext is used Environment Variable F_UFMTENDIAN Method This little endian to big endian conversion feature is intended for Fortran unformatted input output operations It enables the development and processing of files with big endian data organization The feature also enables processing of the files developed on processors that accept big endian data format and producing the files for such processors on IA 32 based little endian systems This little endian to big endian conversion is accomplished by the following operations e The WRITE operation converts little endian format to big endian format e The READ operation
121. OSTAT specifier 00neaeeeaennnae 222 ip compiler option 71 ip_no_inlining compiler option 71 ip_no_pinlining compiler option 71 PF_flt_eval_method0O compiler a 9 01g EE 55 PF_fltacc compiler option 55 IPF_fma compiler option 55 IPF_fp_ speculation compiler option EEN 55 ipo compiler option 71 ipo_c compiler option 71 ipo_obj compiler option 71 ipo_S compiler option 71 ISNAN intrinsic function 119 ivdep_parallel compiler option 71 K key files Met 237 Ianumg based 238 L L compiler option sssssssssseesseeeee 62 language opiions 60 ld See linker EE 7 de LD_LIBRARY_PATH environment variable 30 233 234 legal mtormation 1 libcprts a le 228 Ibcprtse some 228 Ibcprtse eo bie 228 libcxa a file os eee cece eeeeeeeeeeeeeeeeee 228 sie e Re UE 228 libcxa so 5 EE 228 libcxaguard a nie 228 libcxaguard so file ee 228 Ibcxagouard so pe 228 libguide a file E 228 libguide so file eeeteeeeeeeeeeeeees 228 Iboude estate aile 228 libguide_stats so le 228 libifcore a file career ake 228 libifcore so file ceeeeeeeeeeeeees 228 Ibifcore so bie 228 libifcoremt a file c cece 228 libifcoremt so file 0 0 228 libifcoremt so 5 fie 228 libifport a BU 228 libifport a library VELITE Ses ere ceca ces E A 229 libifport so TE 228 sell SUE 228 Intel Fortran Compiler for
122. R I_NUMBER Inquiry by Output Item List Unlike inquiry by unit or inquiry by name inquiry by output item list does not attempt to access any external file It returns the length of a record for a list of variables that would be used for unformatted WRITE READ and REWRITE statements The following INQUIRE statement returns the maximum record length of the variable list in variable RECLENGTH This variable is then used to specify the RECL value in the OPEN statement NQUIRE IOLENGTH I_RECLENGTH A B H OPEN FILE test dat FORM UNFORMATTED RECL I_RECLENGTH UNIT 9 For an unformatted file the RECL value is returned using 4 byte units unless you specify the assume byterecl option to request 1 byte units Closing a File CLOSE Statement Usually any external file opened should be closed by the same program before it completes The CLOSE statement disconnects the unit and its external file You must specify the unit number UNIT specifier to be closed 155 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications You can also specify e Whether the file should be deleted or kept STATUS specifier e Error handling information ERR and IOSTAT specifiers To delete a file when closing it e Inthe OPEN statement specify the ACTION keyword such as ACTION READ Avoid using the READONLY keyword because a file o
123. RANGEERR An integer value appears in a context where the value of the integer is outside the permissible range 151 Tsevere 151 Allocatable array is already allocated FOR IOS_INVREALLOC An allocatable array must not already be allocated when you attempt to allocate it You must deallocate the array before it can again be allocated 152 severe 152 Unresolved contention for Intel Fortran RTL global resource FOR IOS_RESACQFAI Failed to acquire a Intel Fortran RTL global resource for a reentrant routine For a multithreaded program the requested global resource is held by a different thread in your program For a program using asynchronous handlers the 255 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications requested global resource is held by the calling part of the program such as main program and your asynchronous handler attempted to acquire the same global resource 153 severe 153 Allocatable array or pointer is not 173 severe 173 A pointer passed to DEALLOCATE allocated FOR IOS_INVDEALLOC A Fortran 90 allocatable array or pointer must already be allocated when you attempt to deallocate it You must allocate the array or pointer before it can again be deallocated points to an array that cannot be deallocated FOR IOS_INVDEALLOC2 A pointer that was passed to DEALLOCATE pointed to an explicit array an array slice or some other type of memory
124. READ and WRITE statements You cannot use file related statements such as OPEN and INQUIRE on an internal file no unit number is used If an internal file is made up of a single character variable array element or substring that file comprises a single record whose length is the same as the length of the character variable array element or substring it contains If an internal file is made up of a character array that file comprises a sequence of records with each record consisting of a single array element The sequence of records in an internal file is determined by the order of subscript progression A record in an internal file can be read only if the character variable array element or substring comprising the record has been defined a value has been assigned to the record Prior to each READ and WRITE statement an internal file is always positioned at the beginning of the first record Scratch Files 142 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Scratch files are created by specifying STATUS SCRATCH in an OPEN statement By default these temporary files are created in and later deleted from the directory specified in the OPEN statement DEFAULTFILE if specified Record Types Record type refers to whether records stored in a file are all the same length are of varying length or use other conventions to define where one record ends and another begins You c
125. REAL 4 numbers the sign bit representation is 0 zero for positive numbers and 1 for negative numbers COMPLEX KIND 8 DOUBLE COMPLEX Representation COMPLEX 8 same as COMPLEX KIND 8 and COMPLEX 16 data is 16 contiguous bytes containing a pair of REAL 8 values stored in IEEE T_floating format The low order 8 bytes contain REAL 8 data that represents the real part 116 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications of the complex data The high order 8 bytes contain REAL 8 data that represents the imaginary part of the complex data as shown below w il REAL Gett He EXPONENT FRACTION IMAGINARY PART EXPONENT FRACTION Zouso The limits and underflow characteristics for REAL 8 apply to the two separate real and imaginary parts of a COMPLEX 8 number Like REAL 8 numbers the sign bit representation is 0 zero for positive numbers and 1 for negative numbers COMPLEX KIND 16 Representation COMPLEX 16 same as COMPLEX KIND 16 or COMPLEX 32 data is 32 contiguous bytes containing a pair of REAL 16 values stored in IEEE style X_floating format The low order 16 bytes contain REAL 16 data that represents the real part of the complex data The high order 16 bytes contain REAL 8 data that represents the imaginary part of the complex data as shown below 127 126 112 111 REAL PART H EXPONENT FRACTION A MACNAPw EXPONENT FRACTION A 16 PART A LJ O6690
126. S or REWIND 47 severe 47 Write to READONLY file FOR IOS_WRIREAFIL A write operation was attempted to a file that was declared ACTION READ or READONLY in the OPEN statement that is currently in effect 48severe 48 Invalid argument to Fortran Run Time Library FOR IOS_INVARGFOR The compiler passed an invalid or improperly coded argument to the Intel Fortran RTL This can occur if the compiler is newer than the RTL in use 51severe 51 Inconsistent file organization FOR IOS_INCFILORG The file organization specified in an OPEN statement did not match the organization of the existing file 53severe 53 No current record FOR IOS_ NO CURREC Attempted to execute a REWRITE statement to rewrite a record when the current record was undefined To define the current record execute a successful READ statement You can optionally perform an INQUIRE statement on the logical unit after the READ statement and before the REWRITE statement No other operations on the logical unit may be performed between the READ and REWRITE statements 55 severe 55 DELETE error FOR IOS_DELERR An error condition was detected by the Intel Fortran RTL I O system during execution of a DELETE statement 57 severe 57 FIND error FOR IOS_FINERR The Intel Fortran RTL I O system detected an error condition during execution of a FIND statement 58 info 58 Format syntax error at or near XX FOR IOS_FMTSYN Chec
127. Signed integer value from 2 147 483 648 to 2 147 483 647 32 bits INTEGER 8 8 bytes Signed integer value from 9 223 372 036 854 775 808 to 64 bits 9 223 372 036 854 775 807 REAL 4 4 bytes REAL 32 bits Signed integer either INTEGER 2 INTEGER 4 or INTEGER 8 The size is controlled by the integer_size nn compiler option The default is integer_size 32 INTEGER 4 Single precision real floating point values in IEEE S_floating format ranging from 1 17549435E 38 to 3 40282347E38 Values between 1 17549429E 38 and 1 40129846E 45 are denormalized subnormal REAL 8 DOUBLE PRECISION 8 bytes 64 bits Double precision real floating point values in IEEE T_floating format ranging from 2 2250738585072013D 308 to 1 7976931348623158D308 Values between 2 2250738585072008D 308 and 4 94065645841246544D 324 are denormalized subnormal REAL 16 EXTENDED PRECISION Extended precision real floating point values in IEEE style X_floating format ranging from 6 4751751 194380251 109244389582276465524996Q 4966 to 1 189731495357231765085759326628007016196477Q4932 16 bytes 128 bits COMPLEX 4 COMPLEX 8 bytes 64 bits Single precision complex floating point values in a pair of IEEE S_floating format parts real and imaginary The real and imaginary parts each range from 1 17549435E 38 to 3 40282347E38 Values between 1 17549429E 38 and 1 4012984
128. Stream Files Stream_LF and Stream_CR Record Type Records are of varying length where the line feed LF or the carriage return CR character serve as record delimiters LF for Stream_LF files and CR for Stream_CR files Stream_LF files must not contain embedded LF characters or use CARRIAGECONTROL LIST Instead specify CARRIAGECONTROL NONE Stream_CR files must not contain embedded CR characters The Stream_LF record type is the usual record type for text files See also Stream_LF and Stream_CR Records Choosing a Record Type Before you choose a record type consider whether your application will use formatted or unformatted data If you are using formatted data you can choose any record type except segmented If you are using unformatted data avoid the Stream Stream_CR and Stream_LF record types The segmented record type can only be used for unformatted sequential access with sequential files You should not use segmented records for files that are read by programs written in languages other than Intel Fortran The Stream Stream_CR Stream_LF and segmented record types can be used only with sequential files 144 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications The default record type RECORDTYPE depends on the values for the ACCESS and FORM specifiers for the OPEN statement The record type of the file is not maintained as an attribute of the file The results of
129. T Neither the PRINT statement nor a WRITE statement with an asterisk in place of a unit number includes an explicit logical unit number Instead both use an implicit internal logical unit number and the FOR_PRINT environment variable If FOR_PRINT is not defined the code PRINT f iolist Of WRITE f iolist writes to stdout standard output If FOR_PRINT is defined as a filename optionally containing a path the specified file would be written to e FOR_READ A READ statement that uses an asterisk in place of a unit number does not include an explicit logical unit number Instead it uses an implicit internal logical unit number and the FOR_READ environment variable If FOR_READ is not defined the code READ f iolist Of READ f iolist reads from stdin standard input If FOR_READ is defined as a filename optionally containing a path the specified file would be read e FOR_TYPE The TYPE statement does not include an explicit logical unit number Instead it uses an implicit internal logical unit number and the FOR_TYPE environment variable If FOR_TYPE is not defined the code TYPE f iolist writes to stdout standard output If FOR_TYPE is defined as a filename optionally containing a path the specified file would be written to e FORT_BUFFERED Lets you request that buffered I O should be used at run time for output of all Fortran I O units except those with output to the terminal This provides a run time mechanism to support
130. TTRIBUTE options argument ATTRIBUTE options formal argument declarations END routine name END INTERFACE The routine statement defines either a FUNCTION or a SUBROUTINE where the choice depends on whether a value is returned or not respectively The optional routine ATTRIBUTE options such as C determine the calling 189 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications naming and argument passing conventions for the routine in the prototype statement The optional argument ATTRIBUTE options such as VALUE and REFERENCE are properties attached to individual arguments The formal argument declarations are Fortran data type declarations Note that the same INTERFACE block can specify more than one procedure For example suppose you are calling a C function that has the following prototype extern void My_Proc int i The Fortran call to this function should be declared with the following INTERFACE block INTERFACE SUBROUTINE my_Proc I DECS ATTRIBUTES C ALIAS My_Proc_ my_Proc INTEGER I END SUBROUTINE my_Proc END INTERFACE Note that except in the ALIAS string the case of My_Proc in the Fortran program does not matter Exchanging and Accessing Data in Mixed Language Programming Exchanging and Accessing Data in Mixed Language Programming Overview You can use several approaches to sharing data
131. Temporary Files Created by the Compiler or Linker How You Can Use the Intel Fortran Compiler The Intel Fortran Compiler has the following variations e The Intel Fortran Compiler for 32 bit Applications is designed for IA 32 systems The IA 32 compilations run on any IA 32 Intel processor and produce applications that run on IA 32 systems This compiler can be optimized specifically for one or more Intel IA 32 processors such as Pentium M Pentium 4 and Xeon e The Intel Fortran Itanium Compiler for Itanium based Applications or native compiler is designed for Itanium architecture systems This compiler runs on Itanium based systems and produces Itanium based applications Itanium based compilations can only operate on Itanium based systems Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications The command to invoke either of these compilers is ifort The Intel Fortran Compiler has a variety of options that enable you to use the compiler features for higher performance of your application The Intel Fortran Compiler enables your software to perform the best on Intel architecture based computers The compiler has several high performance optimizations Some of its features and benefits are What feature might you want How will this help you to use Support for Streaming SIMD Intel microarchitecture benefit Extensions SSE and Streaming SIMD Extensions 2
132. U Te E 242 FOR IOS_OPEFAI error message 273 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications FOR IOS_OPEREQSEE error Le ar chat earthed 242 FOR IOS_OPEREQSEQ error WU Le sttcetie tient aticntoesransien 242 FOR IOS_OPERREQDIS error MESSAGE E 242 FOR IOS_OUTCONERR error WU ies idedceccveedsceasdadedncne 242 FOR IOS_OUTSTAOVE error Wu vais eranan ane cavern 242 FOR IOS_ PERACCFIL error UE Le EE 242 FOR IOS_ PROABOUSE error WME SS AGS EE 242 FOR IOS_RANGEERR error MESSAGE icsccciciccssccerccwiecctecianss 242 FOR IOS_RECIO_OPE error WEE 242 FOR IOS_ RECNUMOUT error MESSAQG ET 242 FOR IOS_RESACQFAI error Message EE 242 FOR IOS_REWERR error message L IEREN 242 FOR IOS_ROPRAND error MESSAGE bit ie aoa wove 242 FOR IOS_SEGRECFOR error We isinin iniii 242 FOR IOS_SHORTDATEARG error MESSAGE EE 242 274 FOR IOS_SHORTTIMEARG error MESSAGE aie ciricatuns octane aehaen 242 FOR IOS_ SHORTZONEARG error MOSSAQE cca ssensceveceeecestcuneneeenees 242 FOR IOS_SIGFPE error message ere eegene 242 FOR IOS_ SIGINT error message RE 242 FOR IOS_SIGIOT error message SE 242 FOR IOS_SIGQUIT error message EE 242 FOR IOS_ SIGSEGV error message EE 242 FOR IOS_SIGTERM error message See EE 242 FOR IOS_STKOVF error message EIEN IE SETENE Tee an eT 242 FOR IOS_STRLENERR error e CET 242 FOR IOS_SUBRNG error message FOR IOS_SUBSTRERR error MOSSAQG ciseccciecstess
133. When opening a file use the UNIT specifier to indicate the unit number Fortran programs are inherently device independent The association between the logical unit number and the physical file can occur at run time Instead of changing the logical unit numbers specified in the source program you can change this association at run time to match the needs of the program and the available resources For example before running the program a script file can set the appropriate environment variable or allow the terminal user to type a directory path file name or both Use the same logical unit number specified in the OPEN statement for other I O statements to be applied to the opened file such as READ and WRITE The OPEN statement connects a unit number with an external file and allows you to explicitly specify file attributes and run time options using OPEN statement specifiers all files except internal files are called external files Certain unit numbers are preconnected to standard devices Unit number 5 is associated with stdin unit 6 with stdout and unit 0 with stderr At run time if units 5 and 6 are specified by a record I O statement such as READ or WRITE without having been explicitly opened by an OPEN statement Intel Fortran implicitly opens units 5 6 and 0 and associates them with their 136 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications respective operating system standard
134. a pointer Error Handling Error Handling Overview See these topics Run Time Library Default Error Processing Run Time Environment Variables Handling Run Time Errors Signal Handling Overriding the Default Run Time Library Exception Handler Obtaining Traceback Information with TRACEBACKQQ Run Time Library Default Error Processing 215 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications During execution your program may encounter errors or exception conditions These conditions can result from any of the following e Errors that occur during I O operations e Invalid input data e Argument errors in calls to the mathematical library e Arithmetic errors e Other system detected errors The Intel Fortran Run Time Library RTL generates appropriate messages and takes action to recover from errors whenever possible A default action is defined for each error recognized by the Fortran RTL The default actions described throughout this chapter occur unless overridden by explicit error processing methods The way in which the Fortran RTL actually processes errors depends upon the following factors e The severity of the error For instance the program usually continues executing when an error message with a severity level of warning or info informational is detected e For certain errors associated with I O statements whether or not an I O error handling specifier was spec
135. a specified line such as 9 is reached the command or commands are executed For example when at 9 print k prints the value of variable K when the program executes source code line 9 when in name command Executes a command or commands When a procedure specified by name is reached the command or commands are executed For example when in calc_ave print k prints the value of variable K when the program begins executing the procedure named calc_ave where Displays the call stack where thread all Displays the stack traces of all threads The debugger supports other special purpose commands For example e You might use the attach and detach commands for programs with very long execution times e The listobj command might be helpful when debugging programs that depend on shared libraries The 1istobj Command displays the names of executables and shared libraries currently known to the debugger Debugging the SQUARES Example Program The example below shows a program called SQUARES that requires debugging The program was compiled and linked without diagnostic messages from either the compiler or the linker However this program contains a logic error in an arithmetic expression Compiler assigned line numbers have been added in the example so that you can identify the source lines to which the explanatory text refers PROGRAM SQUARES NTEGER NARR 10 OUTARR 10 N
136. age SIGFPE Floating point exception number 75 SIGINT Process interrupted number 69 SIGIOT IOT trap signal number 76 SIGQUIT Process quit number 79 SIGSEGV Segmentation fault number 174 SIGTERM Process killed number 78 Calling the signal routine specifying the numbers for these signals results in overwriting the signal handling facility set up by the Intel Fortran RTL The only way to restore the default action is to save the returned value from the first call to signal When using a debugger it may be necessary to enter a command to allow the Intel Fortran RTL to receive and handle the appropriate signals Overriding the Default Run Time Library Exception Handler To override the default run time library exception handler your application must call signal to change the action for the signal of interest For example assume that you want to change the signal action to cause your application to call abort and generate a core file The following example adds a function named clear_signal_ to call signal and change the action for the SIGABRT signal include lt signal h gt void clear_signal_ 224 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Signal SIGABRT SIG_DFL int myabort_ abort return 0 A call to the clear_signal local routine must be added to main Make sure that the call appears before any call
137. ags are described in the header file usr include sys file h or open 2 4 The create mode protection needed when creating a file is described in open 2 5 The fourth argument is the logical unit number 6 The fifth last argument is the pathname length hidden length argument of the pathname Of the arguments the open system call see open 2 requires the passed pathname the open flags that define the type access needed whether the file exists and so on and the create mode The logical unit number specified in the OPEN statement is passed in case the USEROPEN function needs it The hidden length of the pathname is also passed When creating a new file the create system call might be used in place of open see create 2 You can usually use other appropriate system calls or library routines within the USEROPEN function In most cases the USEROPEN function modifies the open flags argument passed by the Intel Fortran RTL or uses a new value before the open or create system call After the function opens the file it must return control to the RTL If the USEROPEN function is written in Fortran declare it as a FUNCTION with an INTEGER KIND 4 result perhaps with an interface block In any case the called function must return the file descriptor as a 4 byte integer to the RTL 164 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications If your application requires that you
138. ain fixed length sequential files you can also access records using direct access The table below shows the main record UO statements by category that can be used in Intel Fortran programs File Type Access and I O Available Statements Form External file sequential access Formatted READ WRITE PRINT ACCEPT TYPE REWRITE 139 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications List directed READ WRITE PRINT ACCEPT TYPE Namelist READ WRITE PRINT ACCEPT TYPE Unformatted READ WRITE REWRITE External file direct access Formatted READ WRITE REWRITE Unformatted READ WRITE REWRITE Internal file Formatted READ WRITE List directed READ WRITE Unformatted None F Note You can use the REWRITE statement only for relative files using direct access Files and File Characteristics Files and File Characteristics Overview See these topics File Organization Internal Files and Scratch Files Record Types Record Overhead Record Length AEU File organization refers to the way records are physically arranged on a storage device Intel Fortran supports two kinds of file organization e Sequential 140 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications e Relative The default file organization is always ORGANIZATION SEQUENTIAL for an OPEN statement The
139. align compiler option 47 alignment compiler options for 47 allocatable arrays Elle WEE 202 allocating common blocks sssseesenneeeeeeen 32 alternative tool locations ee Le E 23 altparam compiler option 60 ansi_alias compiler option 64 array assignment seers 99 262 array declaratpons 205 array descriptor handling He rte tect tect tent 205 array descriptor format description of 205 array pointers handling WEE 202 array Sechon 99 GENEE A e Sethi SE 238 array Variable E 99 arrays C 205 ln DE 205 handling DE 205 as assembler 6 7 assemblers eseeeseseseeeerr resserrer 7 assigning fles E 147 assignment to arrays eee 99 assume no bscc compiler option 28 assume buffered_io compiler option sian Mh EAEE EATE E stants EE 71 assume byterecl compiler option 47 assume Cc_omp compiler option GA assume dummy_aliases compiler el tel DEE 47 assume minusO compiler option 55 assume none compiler option 64 assume protect_constants compiler OPON WEEN 47 assume underscore compiler option ATTRIBUTES properties and mixed language programming EE 183 effect on character strings 209 ATTRIBUTES properties 189 202 auto compiler option 0 47 auto_ilp32 compiler option 71 auto_scalar compiler option 47 automatic compiler option 47 automatic vechortzer 5 ax compiler option 71 B
140. alue of zero is returned to the shell e The program stops with a STOP or a PAUSE statement A value of zero is returned to the shell e The program stops because of a signal that is caught but does not allow the program to continue A value of 1 is returned to the shell e The program stops because of a severe run time error The error number for that run time error is returned to the shell e The program stops with a CALL EXIT statement The value passed to EXIT is returned to the shell Forcing a Core Dump for Severe Errors 219 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications You can force a core dump for severe errors that do not usually cause a core file to be created Before running the program set the decfort_dump_flag environment variable to any of the common TRUE values Y y Yes yEs True and so forth to cause severe errors to create a core file For instance the following C shell command sets the decfort_dump_flag environment variable setenv decfort_dump_flag y The core file is written to the current directory and can be examined using a debugger 5 Note If you requested a core file to be created on severe errors and you don t get one when expected the problem might be that your process limit for the allowable size of a core file is set too low or to zero See the man page for your shell for information on setting process limits For example the C shell command limit w
141. an Compiler for Linux Systems User s Guide Volume Building Applications Record Variables To display the value of a field in a record structure enter the variable name as the record name a delimiter either a period or a percent sign and the field name To view all fields in a record structure enter the name of the record structure such as REC instead of REC CHR or REC CHR in the previous example Pointer Variables Intel Fortran supports two types of pointers e Fortran 95 90 pointers standard conforming e Integer pointers extension to the Fortran 95 90 standards Fortran 95 90 Pointers Fortran 95 90 pointers display their corresponding target data with a print command Comments keyed to the callouts at the right follow the example ifort g point f 90 idb a out Linux Application X X Build xxxx object file name Debugger for xx bit applications a out Version Reading symbolic information done idb stop in ptr 1 stop in ptr idb list 1 13 1 program ptr 2 3 integer target x 3 4 integer pointer xp 5 6 x 1 2 3 7 xp gt X 8 9 print x X 10 print xp xp SE 12 end idb run 1 stopped at ptr 6 0x120001838 6 x 1 2 3 100 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications idb whatis x int x 1 3 idb whatis xp 1 int xe Cs
142. an use fixed length and variable length record types with sequential or relative files You can use any of the record types with sequential files Relative files require the fixed length record type When creating a new file or opening an existing file specify one of the record types described below See also Format of Record Types Fixed Length Record Type Records in a file must be the same length You must specify the record length RECL when the file is opened See also Fixed Length Records Variable Length Record Type Records in a file can vary in length Record length information is stored as control bytes at the beginning and end of each record See also Variable Length Records Segmented Record Type This pertains to a single logical record containing one or more unformatted records of varying length which can only be used for unformatted sequential access 143 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Avoid the segmented record type when the application requires that the same file be used for programs written in languages other than Fortran and for non Intel platforms See also Sesgmented Records Stream Record Type A stream file is not grouped into records and uses no record delimiters Stream files contain character or binary data that is read or written to the extent of the variables specified Specify CARRIAGECONTROL NONE for stream files See also
143. anization file can only be done if the file resides on disk and contains fixed length records The table below summarizes the types of access permitted for the various combinations of file organizations and record types Record Type Sequential Access Direct Access Sequential file organization Fixed Yes Yes Variable Yes No Segmented Yes No 158 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Stream Yes No Stream_CR Yes No Stream_LF Yes No Relative file organization Fixed Yes Yes S Note Direct access and relative files require that the file resides on a disk device File Sharing Depending on the value specified by the ACTION or READONLY specifier in the OPEN statement the file will be opened by your program for reading writing or both reading and writing records This simply checks that the program itself executes the type of statements intended For performance reasons record locking and shared file checking are not supported by Intel Fortran When you open the file access is always granted regardless of whether e The OPEN statement SHARED specifier was specified e Other processes have already opened the file You might open a file for writing records or reading and writing records and know another process might simultaneously have the file open and be writing records In this case you need to coordinate a
144. aracter in character literals The default assume nobscc assume no BackSlashControlCharacters tells the compiler to treat the backslash character as a normal character instead of a control character in character literals This option is useful when transferring programs from non UNIX environments such as OpenVMS convert Default None Specifies the format of unformatted files containing numeric data Possible values are convert big_endian convert cray convert ibm convert little_endian convert native convert vaxg convert vaxd See Supported Native and Nonnative Numeric Formats no f77rtl Default nof77rt1 Specifies the use of FORTRAN 77 run time behavior If you use the default value nof77rt1 Intel Fortran run time behavior is used Specifying this option controls control the following run time behavior e When the unit is not connected to a file some INQUIRE specifiers will return different values NUMBER returns 0 ACCESS returns UNKNOWN 37 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications BLANK returns UNKNOWN FORM returns UNKNOWN e List directed input for character strings must be delimited by apostrophes or quotation marks or an error will result e When processing NAMELIST input Column 1 of each record is skipped The or amp that appears prior to the group name must appear in column 2 of the input record fpscomp all and fpsco
145. arallelization Enabling Options Directives and Environment Variables parallel Default Off Enables the auto parallelizer to generate multithreaded code for loops that can be safely executed in parallel To use this option you must also specify 02 or SE See also these topics in Volume II Auto Parallelization Overview Auto Parallelization Enabling Options Directives and Environment Variables prefetch IA 32 systems only Default prefetch on Enables prefetch insertion optimization The goal of prefetching is to reduce cache misses by providing hints to the processor about when data should be loaded into the cache Note that 03 must be specified for this option to work To disable the prefetch insertion optimization use prefetch 77 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications prof_dir dir Default The directory where the program is compiled Specifies the directory in which you intend to place the profiling output files dyn and dpi to be created The specified directory must already exist See also these topics in Volume II Advanced PGO Options Specific Coding Guidelines for IA 32 Architecture prof_file file Default Source file name with extension dyn and dpi Specifies the file name for the profiling summary file See also these topics in Volume II Advanced PGO Options Specific Coding Guidelines for A 32 Architecture prof_gen Def
146. ariable for a set of units before any files are opened The environment variable is named F_LUFMTENDIAN See Environment Variable F_UFMTENDIAN Method e Specifying the CONVERT keyword in the OPEN statement for a specific unit number See OPEN Statement CONVERT Method e Compiling the program with an OPTIONS statement that specifies the CONVERT keyword qualifier This method affects all unit numbers using unformatted data specified by the program See OPTIONS Statement Method e Compiling the program with the command line convert keyword option which affects all unit numbers that use unformatted data specified by the program See Compiler Option convert Method If none of these methods are specified the native LITTLE_ENDIAN format is assumed no conversion occurs between disk and memory Any keyword listed in Supported Native and Nonnative Numeric Formats can be used with any of these methods except for the Environment Variable F_UFMTENDIAN Method which supports only LITTLE_ENDIAN and BIG_ENDIAN If you specify more than one method the order of precedence when you open a file with unformatted data is to 1 Check for an environment variable FORT_CONVERTn for the specified unit number applies to any file opened on a particular unit 2 Check for an environment variable FORT_CONVERT ext is checked before FORT_CONVERT_ ext for the specified file name extension applies to all files opened with the specified file name extension
147. ary when you are testing for example set the environment variable LD_LIBRARY_PATH as described in 1d 1 e To install a system wide shared library place the shared library file in one of the standard directory paths used by 1a See 1d 1 Allocating Common Blocks You can use the dyncom dynamic common option to control the allocation of common blocks at run time This option designates a common block to be dynamic The space for its data is allocated at run time rather than compile time On entry to each routine containing a declaration of the dynamic common block a check is made of whether space for the common block has been allocated If the dynamic common block is not yet allocated space is allocated at the check time 30 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications The following command line example specifies the dynamic common option with the names of the common blocks to be allocated dynamically at run time ifort dyncom blk1 b1k2 b1k3 test f where b1k1 b1k2 and b1k3 are the names of the common blocks to be made dynamic Guidelines for Using the dyncom Option The following are some limitations that you should be aware of when using the dyncom option e Anentity in a dynamic common cannot be initialized in a DATA statement e Only named common blocks can be designated as dynamic COMMON e An entity in a dynamic common block must not be used in an EQUIVA
148. as a pointer of the appropriate data type and passed as usual e The argument received by the Fortran routine should be declared as an integer pointer name and the POINTER statement should associate it with a pointee of the appropriate data type matching the data type of the 202 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications passing routine When inside the Fortran routine use the pointee to set and access what the pointer points to For example Fortran subroutine SUBROUTINE Iptr_Sub p DECS ATTRIBUTES C ALIAS Iptr_Sub Iptr_Sub integer VAR 10 POINTER p VAR OPEN 8 FILE STAT DAT READ 8 VAR 4 Read from file and store the fourth element of VAR END SUBROUTINE Iptr_Sub l C main program extern void Iptr_Sub int p main void int a 10 Iptr_Sub amp a 0 printf a 3 i n a 3 When the main C program and Fortran subroutine are built and executed the following output appears if the STAT DAT file contains 4 Handling Arrays and Fortran Array Descriptors Fortran 95 90 allows arrays to be passed as array elements as array subsections or as whole arrays referenced by array name Within Fortran array elements are ordered in column major order meaning the subscripts of the lowest dimensions vary first When using arrays between Fortran and another language diff
149. assing arguments between Fortran and C in mixed language programming PATH environment variable pathname F10 16 0 gt default rules for applying EE EE pc compiler option pg compiler option phases compilation E pointer passing in mixed language Drogramming receiving in mixed language Drogramming pointer variable seee0eeeeee portability library 192 OVETV OW eeeeeeeeeceeeeeeeeeeeeeeees 229 USING RE 229 portability library eeeee 230 portability route 230 porting nonnative data 136 POSITION specifier in OPEN staiement 160 PowerStation compatibility 174 prec_div compiler option 64 preconnected file preconnected files 147 151 predefined preprocessor symbol 25 prefetch compiler option 71 preprocess Dhase 7 preprocessor Symbol 25 preventing linking snsseeeeseeeeee 16 PRINT statement 138 139 147 158 procedure CES 190 procedure names in mixed language programming EE 188 procedures 285 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications user supplied OPEN 164 process control routines 230 processor dispatch cccccee 5 prof_dir compiler option 71 prof_file compiler option 71 prof_format_
150. ate syntax nus filename Appends an underscore character to external user defined names the main program name named COMMON BLOCK DATA global data names in MODULEs and names implicitly or explicitly declared EXTERNAL The name of blank COMMON remains _BLNK and Fortran intrinsic names are not affected If you want to specify a particular filename in which you don t want to append an underscore use nus filename no mixed_str_len_arg Default nomixed_str_len_arg 52 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Tells the compiler that the hidden length passed for a character argument is to be placed immediately after its corresponding character argument in the argument list The default value places the hidden lengths in sequential order at the end of the argument list When porting mixed language programs that pass character arguments either this option must be specified correctly or the order of hidden length arguments changed in the source code See also Programming with Mixed Languages Overview and related sections names keyword Default names lowercase Controls how the case sensitivity of letters in source code identifiers and external names is handled This naming convention applies whether names are being defined or referenced This option is useful in mixed language programming keyword is one of the following e uppercase Causes the compiler to ignore case d
151. ation The compiler calls this routine at the beginning of each routine in a program that contains a dynamic common block In turn this library routine calls _FTN_ALLOC to allocate memory By default the compiler passes the size in bytes of the common block as declared in each routine to f90_dyncom and then on fo EIN ALL OCL If you use the nonstandard extension having the common block of the same name declared with different sizes in different routines you might get a run time error depending on the order in which the routines containing the common block declarations are invoked The Fortran run time library contains a default version of FTN ALL OC which simply allocates the requested number of bytes and returns Compiler Options Compiler Options Overview See these topics Compiler Options Details Compiler Directives Related to Options Code Generation Options Compatibility Options Compilation Diagnostics Options Data Options External Procedures Options Floating Point Options Language Options 32 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Libraries Options Miscellaneous Options Optimization Options Output Files Options Preprocessor Options Run Time Options Compiler Options Details Options to the ifort command affect how the compiler processes a file in conjunction with the file name suffix The simplest form of the ifort command is often sufficient Sty
152. ault Off Instruments a program for profiling to get the execution count of each basic block See also these topics in Volume II Basic PGO Options Example of Profile Guided Optimization prof_use Default Off Enables use of profiling information including function splitting and function grouping during optimization Instructs the compiler to produce a profile optimized executable and merges available profiling output files into a pgopti dpi file If you use this option it automatically enables fnsplit Note that there is no way to turn off function grouping if you enable it using this option 78 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications See also these topics in Volume II Basic PGO Options Example of Profile Guided Optimization scalar_rep IA 32 systems only Default scalar_rep on Enables scalar replacement performed during loop transformation Requires 03 tppn Default value for IA 32 systems tpp7 Default value for Itanium based systems tpp2 Optimizes for a particular Intel processor The executable will run on other processors but is optimized for processors noted below Possible choices for n are e 1 Optimize for Itanium processors Itanium based systems only e 2 Optimize for Itanium 2 processors Itanium based systems only e 5 Optimize for Intel Pentium and Pentium with MMX technology processors IA 32 systems only
153. axP Intel Pentium 4 processors with Streaming SIMD Extensions 3 SSE3 instruction support complex_limited_range Default Off complex_limited_range Enables the use of basic algebraic expansions of some arithmetic operations involving data of type COMPLEX This can result in performance improvements in programs that use a lot of COMPLEX arithmetic However values at the extremes of the exponent range might not compute correctly f no alias Default falias Specifies that aliasing should be assumed in the program See also f no fnalias f no fnalias Default ffnalias Specifies that aliasing should be assumed within functions The fno fnalias option specifies that aliasiing should not be assumed within functions but should be assumed across calls See also f no Jalias fast Default Off Provides a shortcut method to enable several optimizations for run time performance The fast option sets the following options to improve performance 71 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications e 03 optimizes for maximum speed and high level optimizations e ipo enables interprocedural optimizations across files e static prevents linking with shared libraries To get the best possible performance you might need to use the option in conjunction with an architecture specific option such as xN To override one of the options set by fast spec
154. be in the form character CHARACTER LEN n or CHARACTER where nis the number of bytes or nis to indicate passed length format HOLLERITH 1 byte 8 Hollerith constants bits per Hollerith character In addition you can define binary bit constants as explained in the Language Reference The following sections discuss the intrinsic data types in more detail Integer Data Representations Logical Data Representations Native IEEE Floating Point Representations Character Representation Hollerith Representation Integer Data Representations Integer Data Representations Overview Integer data lengths can be 1 2 4 or 8 bytes in length The default data size used for an INTEGER data declaration is INTEGER 4 same as INTEGER KIND 4 unless the integer_size 16 or the integer_size 64 option was specified Integer data is signed with the sign bit being 0 zero for positive numbers and 1 for negative numbers The following sections discuss integer data 110 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications INTEGER KIND 1 Representation INTEGER KIND 2 Representation INTEGER KIND 4 Representation INTEGER KIND 8 Representation INTEGER KIND 1 Representation INTEGER 1 values range from 128 to 127 and are stored in 1 byte as shown BINARY NUM BER A og 8 O i zK 551 AGE Integers are stored in a two s complement representation For example 22
155. between mixed language routines which can be used within the individual languages as well Generally if you have a large number of parameters to work with or you have a large variety of parameter types you should consider using modules or external data declarations This is true when using any given language and to an even greater extent when using mixed languages See also Using Modules in Fortran C Mixed Language Programming See these topics 190 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Passing Arguments in Mixed Language Programming Using Common External Data in Mixed Language Programming Passing Arguments in Mixed Language Programming You can pass data between Fortran C and C through calling argument lists just as you can within each language for example the argument list a b and c in CALL MYSUB a b c There are two ways to pass individual arguments e By value which passes the argument s value e By reference which passes the address of the arguments On IA 32 systems Fortran C and C use 4 byte addresses On Itanium based systems these languages use 8 byte addresses You need to make sure that for every call the calling program and the called routine agree on how each argument is passed Otherwise the called routine receives bad data The Fortran technique for passing arguments changes depending on the calling convention specified By defa
156. ccess times among those processes to handle the possibility of simultaneous WRITE and REWRITE statements on the same record positions Specifying the Initial Record Position When you open a disk file you can use the OPEN statement POSITION specifier to request one of the following initial record positions within the file e The initial position before the first record POSITION REWIND A sequential access READ or WRITE statement will read or write the first record in the file e A point beyond the last record in the file POSITION APPEND just before the end of file record if one exists For a new file this is the initial position before the first record same as REWIND You might specify APPEND before you write records to an existing sequential file using sequential access 159 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications e The current position POSITION ASIS This is usually used only to maintain the current record position when reconnecting a file The second OPEN specifies the same unit number and specifies the same file name or omits it which leaves the file open retaining the current record position However if the second OPEN specifies a different file name for the same unit number the current file will be closed and the different file will be opened The following I O statements allow you to change the current record position e REWIND sets the record po
157. ce_include 82 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Specifies the directory searched for module files specified by a USE statement or source files specified by an INCLUDE statement Possible values are e assume source_include Search in source file directory e assume nosource_include Search in current directory Note that you can use this option whether or not you use the fpp option Dname value Default Off Specifies one or more definitions for use with conditional compilation directives or the Fortran preprocessor fpp If you have more than one use separate D options The value can be a character or integer value If value not specified 1 is assumed to be the value for name For an example see Defining Preprocessor Symbols S Note Do not use D for name because it will conflict with the DD option alternate syntax for d_l ines However you can use the Dname n syntax such as DD 1 no fpp Default nofpp Alternate syntax no cpp also fpp 0 is equivalent to nofpp also fpp n where n is any number greater than 0 is equivalent to fpp Invokes the FPP Preprocessor fpp prior to compilation enabling preprocessor directives cpp is the same as fpp runs fpp not the C preprocessor ldir Default Include path 83 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Specif
158. d The EXCEPTION keyword and the colon can be omitted The default when the keyword is omitted is big e Each list member U is a simple unit number or a number of units The number of list members is limited to 64 decimal is a non negative decimal number less than 2 The command line for the variable setting in the shell is Sh export F_UFMTENDIAN MODE EXCEPTION F Note The environment variable value should be enclosed in quotes if the semicolon is present Another Possible Environment Variable Setting The environment variable can also have the following syntax F_UFMTENDIAN u u 130 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications The command line for the variable setting in the shell is Sh export F_UFMTENDIAN u u Usage Examples 1 F_UFMTENDIAN big All input output operations perform conversion from big endian to little endian on READ and from little endian to big endian on WRITE 2 F_UFMTENDIAN little big 10 20 or F_UFMTENDIAN big 10 20 or F_UFMTENDIAN 10 20 In this case only on unit numbers 10 and 20 the input output operations perform big little endian conversion 3 F_UFMTENDIAN big little 8 In this case on unit number 8 no conversion operation occurs On all other units the input output operations perform big little endian conversion 4 F_UFMTENDIAN 10 20 Define 10 11 12 19 20 un
159. d data fix the source code if necessary and recompile and relink the program If your program encounters unaligned data at run time to make it easier to debug the program you should recompile and relink with the fpen option to control the handling of exceptions To determine the cause of the unaligned data when using idb follow these steps 1 Run the debugger specifying the program with the unaligned data shown as testprog in the following example idb testprog 2 Before you run the program enter the catch unaligned command idb catch unaligned 3 Run the program idb run Unaligned access pid 28413 lt testprog gt va 140000154 pc 3ff80805d60 ra 1200017e8 type stl Thread received signal BUS stopped at oops 13 0x120001834 13 end 4 Enter a list command to display the source code at line 12 idb list 12 12 i4 1 gt I3 end 5 Enter the where command to find the location of the unaligned access idb where 6 Use any other appropriate debugger commands needed to isolate the cause of the unaligned data such as up list and down 7 Repeat these steps for other areas where unaligned data is reported Use the rerun command to run the program again instead of exiting the debugger and running it from the shell prompt 107 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications 8 After fixing the causes of the unaligned data compile and link the program agai
160. do not specify this option A caution If a program compiled with this option is executed on a processor that lacks the specified set of instructions it can fail with an illegal instruction exception or display other unexpected behavior In particular programs compiled with xN xB or xP will emit run time errors if they are executed on unsupported processors Output Files Options The output options let you specify names and directory locations for files that result from the compilation Descriptions of Output Files Options C Default Off Specifies that the compiler should compile to object o file only and not link fcode asm Default Off 80 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Specifies that the compiler should produce an assembly file with optional code annotations This option requires the use of the s option fsource asm Default Off Specifies that the compiler should produce an assembly file with optional source annotations This option requires the use of the s option f no verbose asm Default On when s is specified Specifies that the compiler should produce an assembly file with compiler comments including options and version information This option requires the use of the s option module path Specifies the directory path where module files file extension mod are placed See also Searching for Include and mod Files ofil
161. e opt intel_fc_80 include for_iosdef for in your program to obtain symbolic definitions for the values of IOSTAT The following example uses the IOSTAT specifier and the for_iosdef for file to handle an OPEN statement error in the FILE specifier CHARACTER LEN 40 FILNM INCLUDE for_iosdef for DO I 1 4 FILNM WRITE 6 Type file name READ 5 FILNM OPEN UNIT 1 FILE FILNM STATUS OLD IOSTAT IERR ERR 100 WRITE 6 Opening file FILNM process the input file CLOSE UNIT 1 STOP 222 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications 100 F IERR EQ FORSIOS_FILNOTFOU THEN WRITE 6 File FILNM does not exist ELSE IF ERR EQ FORSIOS FILNAMSPE THEN WRITE 6 File FILNM was bad enter new file name ELSE PRINT Unrecoverable error code IERR STOP END IF END DO WRITE 6 File not found Type 1s to find file and run again END PROGRAM Another way to obtain information about an error is the ERRSNS subroutine which allows you to obtain the last I O system error code associated with an Intel Fortran RTL error see the ntel Fortran Language Reference Signal Handling A signalis an abnormal event generated by one of various sources such as e A user of a terminal e Program or hard
162. e Unformatted data avoids the translation process so I O tends to be faster e Unformatted data avoids the loss of precision in floating point numbers when the output data will subsequently be used as input data e Unformatted data conserves file storage space stored in binary form To write data to a file using formatted list directed or namelist I O statements specify FORM FORMATTED when opening the file To write data to a file using unformatted I O statements specify FORM UNFORMATTED when opening the file Data written using formatted list directed or namelist I O statements is referred to as formatted data data written using unformatted I O statements is referred to as unformatted data When reading data from a file you should use the same I O statement form that was used to write the data to the file For instance if data was written to a file with a formatted I O statement you should read data from that file with a formatted I O statement Although I O statement form is usually the same for reading and writing data in a file a program can read a file containing unformatted data using unformatted input and write it to a separate file containing formatted data using formatted output Similarly a program can read a file containing formatted data and write it to a different file containing unformatted data You can access records in any sequential or relative file using sequential access For relative files and cert
163. e and allows you to explicitly specify file attributes and run time options using OPEN statement specifiers Once you open a file you should close it before opening it again unless it is a preconnected file If you open a unit number that was opened previously without being closed one of the following occurs e f you specify a file specification that does not match the one specified for the original open the Intel Fortran run time system closes the file and then reopens it This resets the current record position for the second file e f you specify a file specification that matches the one specified for the original open the file is reconnected without the internal equivalent of the CLOSE and OPEN This lets you change one or more OPEN statement run time specifiers while maintaining the record position context You can use the INQUIRE statement to obtain information about whether or not a file is opened by your program Especially when creating a new file using the OPEN statement examine the defaults see the description of the OPEN statement in the Intel Fortran Language Reference Manual or explicitly specify file attributes with the appropriate OPEN statement specifiers Specifiers for File and Unit Information These specifiers identify file and unit information e UNIT specifies the logical unit number e FILE or NAME and DEFAULTFILE specify the directory and or file name of an external file e STATUS or TYPE indicates wh
164. e code sent to the compiler the value 100 replaces SIZE in this declaration and in all other occurrences of the name SIZE Suppressing Preprocessor Symbols You can use the u option to suppress an automatic definition of a preprocessor symbol This option suppresses any symbol definition currently in effect for the specified name The u option performs the same function as an undef preprocessor directive Redirecting Command Line Output to Files For programs that display a lot of text consider redirecting text that is usually displayed on stdout to a file Displaying a lot of text will slow down execution scrolling text in a terminal window on a workstation can cause an I O bottleneck increased elapsed time and use more CPU time The following commands show how to run the program more efficiently by redirecting output to a file and then displaying the program output myprog gt results lis more results 1lis Redirecting output from the program will change the times reported because of reduced screen I O Creating Running and Debugging an Executable Program The example below shows a sample Fortran main program using free source form that uses a module and an external subprogram The function CALC_AVERAGE is contained in a separate file and depends on the module ARRAY_CALCULATOR for its interface block 25 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications The USE sta
165. e following i fort command compiles multiple source files ifort o circle out circle calc f90 sub f90 Because the c option was omitted an executable program named circle out is created Specifying an Additional Linker Library 15 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications The following ifort command compiles a free format source file myprog 90 using default optimization and passes an additional library for the linker to search ifort typedefs_1 o myprog f90 lmylib The file is processed at optimization level 02 and then linked with the object file typedefs_1 0 The 1my1ib option instructs the linker to search in the libmylib library for unresolved references in addition to the standard list of libraries the ifort command passes to the linker Using Module mod Files A module mod file is a type of program unit that contains specifications of such entities as data objects parameters structures procedures and operators These precompiled specifications and definitions can be used by one or more program units Partial or complete access to the module entities is provided by the USE statement Typical applications of modules are the specification of global data or the specification of a derived type and its associated operations Some programs require modules located in multiple directories You can use the Idir option when you compile the program to locate the mod
166. e maximum record number for direct access e ASSOCIATEVARIABLE specifies the variable containing the next record number for direct access Specifiers for Record Transfer Characteristics These specifiers identify record transfer characteristics e BLANK indicates whether to ignore blanks in numeric fields e DELIM specifies the delimiter character for character constants in list directed or namelist output e PAD when reading formatted records indicates whether padding characters should be added if the item list and format specification require more data than the record contains e BLOCKSIZE specifies the block physical UO buffer size e BUFFERCOUNT specifies the number of physical I O buffers e CONVERT specifies the format of unformatted numeric data Specifiers for Error Handling Capabilities These specifiers are used for error handling e ERR specifies a label to branch to if an error occurs e IOSTAT specifies the integer variable to receive the error IOSTAT number if an error occurs Specifier for File Close Action 152 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications DISPOSE identifies the action to take when the file is closed Coding File Locations in an OPEN Statement You can use the FILE and DEFAULTFILE specifiers of the OPEN statement to specify the complete definition of a particular file to be opened on a logical unit The Language Reference Manual describes the OPEN
167. e program process leaving the debugger 91 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications running and its breakpoints and tracepoints intact for when the program is rerun list Displays source program lines To list a range of lines add the starting line number a comma and the ending line number such aS list 1 9 print k Displays the value of the specified variable such as K printregs Displays all registers and their contents next Steps one source statement but does not step into calls to subprograms Compare with step quit Ends the debugging session run Runs the program being debugged You can specify program arguments and redirection rerun Runs the program being debugged again You can specify program arguments and redirection return routine name Continues execution of the function until it returns to its caller When using the step command if you step into a subprogram that does not require further investigation use the return command to continue execution of the current function until it returns to its caller If you include the name of a routine with the return command execution continues until control is returned to that routine The rout ine name is the name of the routine usually named by a PROGRAM SUBROUTINE or FUNCTION statement If there is no PROGRAM statement the debugger refers to the main
168. e routine with an explicit interface and specify the dummy array as either an assumed shape array or with the pointer attribute You can associate a Fortran 95 90 pointer with any piece of memory organized in any way desired so long as it is rectangular in terms of array bounds You can also pass Fortran 95 90 pointers to other languages such as C and have the other language correctly interpret the descriptor to obtain the information it needs However using array descriptors can increase the opportunity for errors and the corresponding code is not portable In particular be aware of the following e If the descriptor is not defined correctly the program may access the wrong memory address possibly causing a General Protection Fault e Array descriptor formats are specific to each Fortran compiler Code that uses array descriptors is not portable to other compilers or platforms For example the current Intel Fortran array descriptor format differs from the array descriptor format for Intel Fortran 7 0 e The array descriptor format may change in the future The components of the current Intel Fortran array descriptor on IA 32 systems are as follows 205 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications e The first longword bytes 0 to 3 contains the base address The base address plus the offset defines the first memory location start of the array e The second longword bytes 4 to
169. e this optimization requires interprocedural analysis over the whole program you must use this option with the ipo option Using this option on programs that exceed 32 bit address space may cause unpredictable results during program execution ax K W N B P IA 32 systems only Default None Directs the compiler to find opportunities to generate separate versions of functions that take advantage of features that are specific to the specified Intel processor If the compiler finds such an opportunity it first checks whether generating a processor specific version of a function is likely to result in a performance gain If this is the case the compiler generates both a processor specific version of a function and a generic version of the function The generic version will run on any IA 32 processor At run time one of the versions is chosen to execute depending on the Intel processor in use In this way the program can benefit from performance gains on more advanced Intel processors while still working properly on older IA 32 processors 70 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Possible values and the processors the code is optimized for are axK Intel Pentium III and compatible Intel processors axw Intel Pentium 4 and compatible Intel processors axN_ Intel Pentium 4 and compatible Intel processors axB_ Intel Pentium M and compatible Intel processors
170. e units for unformatted files This option e Specifies that the units for an explicit OPEN statement RECL specifier value are in bytes e Forces the record length value returned by an INQUIRE by output list to be in byte units The default value assume nobyterecl specifies that the units for RECL values with unformatted files are in four byte longword units assume no dummy_aliases Default assume nodummy_aliases 47 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Alternate syntax common_args Requires that the compiler assume that dummy formal arguments to procedures share memory locations with other dummy arguments or with variables shared through use association host association or common block use You only need to compile the called subprogram with assume dummy_aliases The program semantics involved with dummy aliasing do not strictly obey the Fortran standard and they slow performance Therefore using the default value assume nodummy_aliases will give the compiler better run time performance However if a program depends on dummy aliasing and you do not specify assume dummy_aliases the run time behavior of the program will be unpredictable In such programs the results will depend on the exact optimizations that are performed In some cases normal results will occur but in other cases results will differ because the values used in computations involving the of
171. ear in this document or any software that may be provided in association with this document Designers must not rely on the absence or characteristics of any features or instructions marked reserved or undefined Intel reserves these for future definition and shall have no responsibility whatsoever for conflicts or incompatibilities arising from future changes to them The Intel Fortran Compiler product may contain software defects which may cause the product to deviate from published specifications Current characterized software defects are available on request Intel SpeedStep Intel Thread Checker Celeron Dialogic i386 i486 iCOMP Intel Intel logo Intel386 Intel486 Intel740 IntelDX2 IntelDX4 IntelSX2 Intel Inside Intel Inside logo Intel NetBurst Intel NetStructure Intel Xeon Intel XScale Itanium MMX MMX logo Pentium Pentium II Xeon Pentium III Xeon Pentium M and VTune are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States and other countries Other names and brands may be claimed as the property of others Copyright Intel Corporation 2003 2004 Portions Copyright 2001 Hewlett Packard Development Company L P Table Of Contents About the Intel Fortran Compiler soit seclctcsiascts ses nacven ues duld EEN 1 How to Use This Document EE 1 Additional Documentation WEE 1 le ele e E 2 Getting STATES sc ate a ee e 3 Getting Started OVErView ENEE 3 How Yo
172. ect access Detecting deleted records is only available if you specified the vms option when the program was compiled When creating a relative file use the RECL value to determine the size of the fixed length cells Within the cells you can store records of varying length as long as their size does not exceed the cell size Internal Files and Scratch Files Intel Fortran also supports two other types of files that are not file organizations 141 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications e Internal files e Scratch files Internal Files When you use sequential access you can use an internal file to reference character data in a buffer The transfer occurs between internal storage and internal storage unlike external files such as between character variables and a character array An internal file consists of any of the following e Character variable e Character array element e Character array e Character substring e Character array section without a vector subscript Instead of specifying a unit number for the READ or WRITE statement use an internal file specifier in the form of a character scalar memory reference or a character array name reference An internal file is a designated internal storage space variable buffer of characters that is treated as a sequential file of fixed length records To perform internal I O use formatted and list directed sequential
173. ed types TYPE statement are not converted When they are later examined as separate fields by the program they will remain in the binary format they were stored in on disk unless the program is modified With EQUIVALENCE statements the data type of the variable named in the I O statement is used If a program reads an I O record containing multiple format floating point fields into a single variable such as an array instead of their respective variables the fields will not be converted When they are later examined as separate fields by the program they will remain in the binary format they were stored in on disk unless the program is modified Methods of Specifying the Data Format 125 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Methods of Specifying the Data Format Overview There are six methods of specifying a nonnative numeric format for unformatted data e Setting an environment variable for a specific unit number before the file is opened The environment variable is named FORT_CONVERTn where n is the unit number See Environment Variable FORT_CONVERTn Method e Setting an environment variable for a specific file name extension before the file is opened The environment variable is named FORT_CONVERT ext or FORT_CONVERT_ ext where ext is the file name extension suffix See Environment Variable FORT _CONVERT ext or FORT CONVERT _ ext Method e Setting an environment v
174. ef for and Its EE Le E 117 Character Representation EE 120 Hollerith Representation E 120 Converting Unformatted Data E 121 Converting Unformatted Data Overview ccceeeeeeeeeeeeeeneeeeeeeeeeeeeeeeenanees 121 xiv Table Of Contents Supported Native and Nonnative Numeric Fommats 122 Limitations of Numeric Conversion ssssssssssssserrrrsesesrrtrrrrrntnsstrrrtrnnnnnneeerrrnee 125 Methods of Specifying the Data Format Overview eseesseeeeeenneeeeneneneeeeen 126 Environment Variable FORT CONVERTN Method 127 Environment Variable FORT _CONVERT ext or FORT_CONVERT_ext RE Se Environment Variable F_UFMTENDIAN Method 129 Little to Big Endian Conversion Environment Variable ssssssseeeeeeeeseeeene 129 F Note SEENEN 130 Another Possible Environment Variable Setting ccceceeeeeeeeeeetees 130 Us ge nl 131 OPEN Statement CONVERT Mietug geet deet ege enke Se eege ees 132 OPTIONS Statement leste eunteeeserges d Eeler 133 Compiler Option convert Method esiuisiiearsimsavadatersuusemmnedeustausierenndebmeatavecansieant 134 Porting ee RT cccaicsisterateratcrnncribasieneheunneribasedsnindanadesindasindeaiebcnndesbhancdenkass 134 BN OO EE 135 Fortran O OWI GW ie ost nitaie e thanta decanted anders deatiaadsanaenindatioceedext 135 eebe lr 136 Types of V O Statements casa sea cicrnercncdircnancneniaanendiicoaadeadecthencherbcenioaantdensmeibiancaecsbant 137 Forms of O EERIEEEeseekengeret ehgee enk
175. efault Off Displays the optimization phases available for reporting See also this topic in Volume II Optimizer Report Generation opt_report_level min med max Default opt_report_level min Specifies the detail level of the optimization report See also this topic in Volume It Optimizer Report Generation opt_report_phase phase Default Off Specifies the optimization phase to generate the report for Can be specified multiple times on the command line for multiple optimizations See also this topic in Volume II Optimizer Report Generation opt_report_routine routine Default Off Generates reports from all routines with names containing routine as part of their name 76 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications If the optional routine is not specified reports from all routines are generated See also this topic in Volume II Optimizer Report Generation par_threshold n Default par_threshold 100 Sets a threshold for the auto parallelization of loops based on the probability of profitable parallel execution n can be from 0 through 100 n 0 loops get auto parallelized regardless of computation work volume that is always n 100 loops get auto parallelized only if profitable parallel execution is almost certain See also these topics in Volume II Auto Parallelization Threshold Control and Diagnostics Auto Parallelization Overview Auto P
176. eger Pointers Integer pointers also known as Cray style pointers are not the same as Fortran 90 pointers but are instead like C pointers Integer pointers are 4 byte INTEGER quantities on IA 32 systems and 8 byte INTEGER quantities on Itanium based systems Passing Integer Pointers 201 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications When passing an integer pointer to a routine written in another language e The argument should be declared in the non Fortran routine as a pointer of the appropriate data type e The argument passed from the Fortran routine should be the integer pointer name not the pointee name For example Fortran main program INTERFACE SUBROUTINE Ptr_Sub p DECS ATTRIBUTES C ALIAS Ptr_Sub Ptr_Sub INTEGER p END SUBROUTINE Ptr_Sub END INTERFACE REAL A 10 VAR 10 POINTER p VAR VAR is the pointee p is the integer pointer p LOC A CALL Ptr_Sub p WRITE A 4 A A4 END C subprogram void Ptr_Sub float p On Itanium based systems the declaration for p in the INTERFACE block should be INTEGER 8 p When the main Fortran program and C function are built and executed the following output appears A 4 23 50000 Receiving Pointers When receiving a pointer from a routine written in another language e The argument should be declared in the non Fortran routine
177. el Fortran Version 8 239 Documentation Information ccccceeeeeeeeeeeceeeeeeeeeeeeeeeeeneaaeeeeeeeeeeeeeeeeeaaees 240 Version 7 1 Features Not Available in Intel Visual Fortran Version 8 240 Run Time Error Messages 241 INGO Xe A ne nice nt aoe a ean alee neha ah a abont 261 xxii About the Intel Fortran Compiler The Intel Fortran Compiler version 8 0 compiles code targeted for the IA 32 Intel architecture and Intel Itanium architecture The Intel Fortran Compiler product includes the following components for the development environment e Intel Fortran Compiler for 32 bit Applications e Intel Fortran Compiler for Itanium based Applications e Intel Debugger idb The Intel Fortran Compiler for Itanium based applications includes the Intel Itanium Assembler and Intel Itanium Linker See also How to Use This Document How to Use This Document This is Volume in the two volume Intel Fortran Compiler for Linux Systems User s Guide t explains how you can use the Intel Fortran Compiler to build applications Volume II explains how to optimize applications This User s Guide provides information on how to get started with Intel Fortran how the compiler operates and how to develop applications This documentation assumes that you are familiar with the Fortran Standard programming language and with the Intel processor architecture You should also be familiar with the host computer s opera
178. emporaries If FOR_DISABLE_STACK_TRACE Is Set no stack trace information is produced See the following example of stack trace information The program generates an error at line 12 program ovf 217 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications real 4 x 5 y 5 integer 4 i x 1 1le32 x 2 Leit x 3 1e38 x 4 1638 x 5 36 0 do i 1 5 y i 100 0 x i Prank s IS Je Riy TD les yL end do end gt ifort 00 fpe0 traceback ovf f90 o ovf exe gt ovf exe x 1 0000000E 32 x 100 0 1 0000000H 34 1 forrtl error 72 floating overflow Image PC Routine Line Source ovf exe O8049F4A MAIN _ 14 ovf 90 ovf exe O8049F08 Unknown Unknown Unknown ovf exe 400B3507 Unknown Unknown Unknown ovf exe 08049C51 Unknow Unknown Unknown Abort gt setenv FOR_DISABLE STACK _TRACE true gt ovf exe x 1 0000000E 32 x 100 0 1 0000000E 34 forrtl error 72 floating overflow 2 Abort The following information corresponds to the numbers at the right of the example 1 Stack trace information when the traceback information is present 2 No stack trace information because the FOR_DISABLE_STACK_TRACE environment variable is set Message Catalog File Location The Intel Fortran RTL uses a message catalog file to store the text associated with each run time message When a run time error occurs the Fo
179. ename Default Off Specifies the name of the output file If c is specified o specifies the name of the object file If s is specified o specifies the name of the assembly listing file If neither c nor sS is specified o specifies the name of the executable file Qinstall dir Default Off Specifies dir as the root directory for the compiler installation Qlocation tool path Default Off 81 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Specifies the directory location of supporting tools specifically the preprocessor compiler assembler and linker For syntax and details see Using Qlocation to Specify an Alternate Location for a Tool Qoption tool options Default Off Passes options to tools specifically the preprocessor compiler assembler and linker For syntax and details see Using Qoption to Pass Options to Tools S Default Off Specifies that the compiler should compile to assembly s file only and not link use_asm Default Off Specifies that objects should be produced through the assembler Preprocessor Options The preprocessor options let you specify how the compiler preprocesses files as an optional first phase of the compilation and where it looks for source directories See Also Preprocessing Phase Predefined Preprocessor Symbols Descriptions of Preprocessor Options assume no source_include Default assume sour
180. equential file that contains segmented records specify FORM UNFORMATTED and RECORDTYPE SEGMENTED when you open the file O As shown in the figure below the layout of segmented records consists of 4 bytes of control information followed by the user data 171 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Spf ome S OO 2 2 H Record length RECL value Record size count rteger 26 9821 GE The control information consists of a 2 byte integer record size count includes the two bytes used by the segment identifier followed by a 2 byte integer segment identifier that identifies this segment as one of the following Identifier Value Segment Identified 0 One of the segments between the first and last segments 1 First segment 2 Last segment 3 Only segment If the specified record length is an odd number the user data will be padded with a single blank one byte but this extra byte is not added to the 2 byte integer record size count Stream File A Stream file is not grouped into records and contains no control information Stream files are used with CARRIAGECONTROL NONE and contain character or binary data that is read or written only to the extent of the variables specified on the input or output statement The figure below shows the layout of a Stream file E User Data 0 F ZK 9522 GE Stream_CR and Stream_LF Records A Stream_
181. er of options or file names on a line in the indirect command file or response file Several files can be referenced in the same command line The syntax for using response files is 21 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications ifort responsefile responsefile2 Note An at sign must precede the name of the response file on the command line Specifying Alternative Tool Locations and Options The Intel Fortran compiler lets you specify alternative tool locations and tool options to be used instead of default tools for preprocessing compilation assembly and linking You can use command line options to do this Using Qlocation to Specify an Alternative Location for a Tool Qlocation lets you specify the pathname location of a supporting preprocessor compiler assembler or linker This option s syntax is Qlocation tool path where tool is e fpp Intel Fortran preprocessor fpp e f Intel Fortran compiler fortcom e c Intel C compiler e as Assembler e link Linker and path is the location of the tool Example ifort Qlocation fpp usr preproc myprog f Using Qoption to Pass Options to Tools Qoption lets you pass options to the preprocessor compiler assembler or linker This option s syntax is Qoption tool options 22 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications where tool is
182. ere an IVDEP directive is specified This technique is useful for some sparse matrix applications See also this topic in Volume II Memory Dependency with the IVDEP Directive nolib_inline Default On Disables inline expansion of intrinsic functions On Default 02 unless you specify debug in which case the default is 00 Specifies the code optimization for application types Possible values are 74 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications 00 Disables all optimizations This is the default if you specify debug with no keyword Specifying this option causes certain warn options to be ignored 01 Alternate syntax on IA 32 systems 02 or O Maximize speed disables some optimizations that increase code size for a small speed benefit This option enables global optimization This includes data flow analysis code motion strength reduction and test replacement split lifetime analysis and instruction scheduling Specifying 02 includes the optimizations performed by 01 Note that on IA 32 systems 01 and 02 are equivalent 02 Alternate syntax on Itanium based systems 0O Minimizes size optimizes for speed but disables some optimizations that increase code size for a small speed benefit for the Itanium compiler O1 turns off software pipelining to reduce code size This option enables local optimizations within the source program unit recognition of
183. erences in element indexing and ordering must be taken into account You must reference the array elements individually and keep track of them Fortran and C vary in the way that array elements are indexed Array indexing is a source level consideration and involves no difference in the underlying data Fortran and C arrays differ in two ways 203 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications e The value of the lower array bound is different By default Fortran indexes the first element of an array as 1 C and C index it as 0 Fortran subscripts should therefore be one higher Fortran also provides the option of specifying another integer lower bound e In arrays of more than one dimension Fortran varies the left most index the fastest while C varies the right most index the fastest These are sometimes called column major order and row major order respectively In C the first four elements of an array declared as X 3 3 are In Fortran the first four elements are X 1 1 X 2 1 X 3 1 X 1 2 The order of indexing extends to any number of dimensions you declare For example the C declaration int arrl 2 10 15 20 is equivalent to the Fortran declaration INTEGER arrl 20 15 10 2 The constants used in a C array declaration represent extents not upper bounds as they do in other languages Therefore the last element in the C array declared as int arr 5
184. erttteeeesstieenditee eek AER EC een 100 IPSCO Geet 101 Array EE negen ee ee 102 Array Sections tanta cates lett ee elt ne elt nt alte ele ac 102 Assignment to E 103 C mplex Ee 103 RE e 104 Expressions in Debugger Commande AAA 104 Fortran Operators ee EE 105 EE 105 Debugging Mixed Language Programs en 105 Debugging a Program that Generates a Signal eceeeeeseeeeeeeenneeeeeeeaes 106 Table Of Contents Locating Unaligned RE innuendo ctl ett Ls 107 Data ne RI sch ae ie eh ie at ta Ne a als Se hs ada E ty Nae lets Me ete at ts E 108 Data Representation eben ent lle el alt lead aiela ne 108 Data Representation OVerview EE 108 edel Data KE 108 Integer Data Representations Overview cceceeeeeeeceeeeeeeeeeeeeeeeneeeeeeeeeeeeeee 110 INTEGER KIND 1 Representation Ae 111 INTEGER KIND 2 Hepresentaton Ae 111 INTEGER KIND 4 Representation Ae 111 INTEGER KIND 8 Hepresentaton Ae 112 Logical Data Representations AEN 112 Native IEEE Floating Point Representations Overview eesseessssserererreesee 113 REAL KIND 4 REAL RHepresentaton un 114 REAL KIND 8 DOUBLE PRECISION Representation c ceeeee 115 REAL KIND 16 EXTENDED PRECISION Hepresentaion 115 COMPLEX KIND 4 COMPLEX Representation cceeeeeeeeeeeeeeeeeteees 116 COMPLEX KIND 8 DOUBLE COMPLEX Hepresentaton 116 COMPLEX KIND 16 Representation cceeeceeeeeeeeeeeeeeeeenneeeeeeeeeeeeeeeeenanees 117 File ford
185. essing 0 1 7 formatted direct files and Microsoft Fortran PowerSation compatibility 174 formatted I O statement 139 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications formatted sequential files and Microsoft Fortran PowerSation compatibility 174 FORT BUFFERED environment NEIE eege ege ees 234 FORT _CONVERT ext environment variable 129 234 FORT_CONVERT ext method 129 FORT _CONVERT_ ext environment Val ue ee e 129 234 FORT_CONVERT_ext method 129 FORT _CONVERTn environment E el 234 FORT_CONVERTn method 128 elei 6 ele 237 238 Fortran Operators ect ee iedee getest ek 106 Fortran 95 90 pointer seeeeeeeane 99 Fortran UO OVEIVICW 2 cecccecceeececceecaeececeees 136 Fortran PowerStation compatibility Se 174 Fortran C mixed language programs OVEVIEW EEN 213 FORTRAN 66 interpretations 60 276 fp compiler optton 71 FP_CLASS intrinsic function 119 fp_port compiler option 55 FPATH environment variable 20 234 fpconstant compiler option 55 fpe compiler option 55 fpic compiler option 30 64 JEE 6 7 fpp TUG tiie Settee aes se 237 238 foscomp compiler option 38 fpstkchk compiler option 55 fr32 compiler option 55 free compiler option 60 free format compiler option Tor 60 FREEFORM compiler di
186. ether to create a new file overwrite an existing file open an existing file or use a scratch file e STATUS or DISPOSE specifies the file existence status after CLOSE Specifiers for File and Record Characteristics These specifiers identify file and record characteristics ORGANIZATION indicates the file organization Sequential or relative RECORDTYPE indicates which record type to use FORM indicates whether records are formatted or unformatted CARRIAGECONTROL indicates the terminal control type 151 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications e RECL or RECORDSIZE specifies the record size Specifier for Special File Open Routine USEROPEN names the routine that will open the file to establish special context that changes the effect of subsequent Intel Fortran I O statements Specifiers for File Access Processing and Position These specifiers identify file access processing and position e ACCESS indicates the access mode direct or sequential e SHARED indicates that other users can access the same file and activates record locking Ignored in the current version of Intel Fortran e POSITION indicates whether to position the file at the beginning of file before the end of file record or leave it as is unchanged e ACTION or READONLY indicates whether statements will be used to only read records only write records or both read and write records e MAXREC specifies th
187. fending aliases will differ For more information see the information about the dummy aliasing assumption in the User s Guide Volume II Optimizing Applications assume no protect_constants Default assume protect_constants Specifies that constants are read only The assume noprotect_constants option tells the compiler to pass a copy of a constant actual argument As a result the called routine can modify this copy even though the Fortran standard prohibits such modification The calling routine does not modify the constant The default assume protect_constants results in passing of a constant actual argument Any attempt to modify it may result in an error auto_scalar auto and save Default auto_scalar unless recursive or openmp is specified in which case the default is auto Alternate syntax for auto automatic and nosave Alternate syntax for save noauto and noautomatic Specifies where local variables are stored if default local storage is not desired 48 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications auto_scalar Causes allocation of scalar variables of intrinsic types INTEGER REAL COMPLEX and LOGICAL to the stack auto_scalar does not affect variables that appear in EQUIVALENCE or SAVE statements or those that are in common blocks auto_scalar may provide a performance gain for your program but if your program depends on variables havi
188. g conventions 6 OF EE rrenetrr rrr 187 C Fortran mixed language lte ICT 216 NATIVE keyword cccccceeeeeees 123 nbs compiler option 38 NLSPATH environment variable 217 234 no_cpprt compiler option 62 noauto compiler option 47 noautomatic compiler option 47 nobss_init compiler option 64 NODECLARE compiler directive 36 nodefaultlios compiler option 62 nofor_main Option cee 64 NOFREEFORM compiler directive 36 282 noinclude compiler option 64 nolib_inline compiler option 71 nomixed_str_len_arg compiler ODUONS erer eege 54 183 209 nonadvancing UC 161 nonadvancing record I O 161 nonnative data DEER 136 nosave compiler option 47 nostartfiles compiler option 64 nostdinc compiler option 64 nostdlib complier option 62 NOSTRICT compiler directive 36 notation conventions ssseeeeeeees 3 Nso assembler option 0 7 numeric conversion limitations of 126 numeric data types handling DE 200 numeric formats WEI 123 ele 123 numeric values and conversion FOULINGS 0 eee eeeeeceeceeceeeeceeceeees 230 nus compiler option 54 O O compiler optton 71 82 obtaining file information See INQUIRE statement 155 Octal conversions n 240 onetrip compiler option
189. g is in the range 1 through 2 147 483 647 2 31 1 Hollerith Representation Hollerith constants are stored internally one character per byte as shown below Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications LKOHOGE Converting Unformatted Data Converting Unformatted Data Overview This section describes how you can use Intel Fortran to read and write nonnative unformatted numeric data See these topics Supported Native and Nonnative Numeric Formats Limitations of Numeric Conversion Methods of Specifying the Data Format Overview Porting Nonnative Data 121 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Supported Native and Nonnative Numeric Formats Intel Fortran supports the following little endian floating point formats in memory Floating point size Format in memory REAL KIND 4 IEEE S_floating COMPLEX KIND 4 REAL KIND 8 IEEE T_floating COMPLEX KIND 8 REAL KIND 16 IEEE X_floating COMPLEX KIND 16 If your program needs to read or write unformatted data files containing a floating point format that differs from the format in memory for that data size you can request that the unformatted data be converted Data storage in different computers uses a convention of either little endian or big endian storage The storage convention generally applies to numeric values that span mult
190. gn reclbyte Zp2 align rec2byte Zp4 align rec4byte align Zp8 with align dcommons align all or align dcommons and align records noalign Zp1 align none Or align nocommons and align nodcommons and align norecords align reclbyte align norecords align rec8byte align records Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications align no records Default align records Requests that components of derived types and fields of records be aligned on natural boundaries up to 8 bytes for derived types with the SEQUENCE statement by adding padding See align sequence The align norecords option requests that components and fields be aligned on arbitrary byte boundaries instead of on natural boundaries up to 8 bytes with no padding align no sequence Default align nosequence Tells the compiler that components of derived types with the SEQUENCE attribute will obey whatever alignment rules are currently in use The default alignment rules align unsequenced components on natural boundaries The default value of align nosequence means that components of derived types with the SEQUENCE attribute will be packed regardless of whatever alignment rules are currently in use If your command line includes the st and option then the compiler ignores align sequence assume no byterecl Default assume nobyterecl Specifies the use of byt
191. guments in which the last dimension bound is specified as or when both upper and lower dimensions are 1 Once the program is debugged omit this option to reduce executable program size and slightly improve run time performance check no format Default check noformat unless vms is specified in which case check format is the default Requests a run time error message when the data type for an item being formatted for output does not match the FORMAT descriptor check no output_conversion Default check nooutput_conversion unless vms is specified in which case check output_conversion is the default Requests a run time error message when format truncation occurs that is when a number is too large to fit in the specified format field length without loss of significant digits no traceback Default notraceback Requests that the compiler generate extra information in the object file that allows the display of source file traceback information at run time when a severe error occurs Specifying t raceback provides source file routine name and line number correlation information in the displayed call stack hexadecimal addresses program counter trace that is displayed when a severe error occurs H traceback is not specified this information is not displayed However advanced users can locate the cause of the error using a map file and the hexadecimal addresses of the stack displayed when a severe error occurs
192. h occurs The EXIST and OPENED specifier variables indicate a true value The pathname and file name are returned in the NAME specifier variable The UNIT number is returned in the NUMBER specifier variable Other information requested on the previously connected file is returned Default values are usually returned for the INQUIRE specifiers also associated with the OPEN statement 154 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications e The RECL value unit for connected formatted files is always 1 byte units For unformatted files the RECL unit is 4 byte units unless you specify the assume byterecl option to request 1 byte units If no match occurs e The OPENED specifier variable indicates a false value e The unit NUMBER specifier variable is returned as a value of 1 e The EXIST specifier variable indicates true or false whether the named file exists on the device or not e Ifthe file does exist the NAME specifier variable contains the pathname and file name e Any other information returned will be default values for the various specifiers based on any information specified when calling INQUIRE The following INQUIRE statement returns whether the file named log_file is connected in logical variable _ OPEN whether the file exists in logical variable EXIST and the unit number in integer variable NUMBER NQUIRE FILE log_file OPENED I_OPEN EXIST I_EXIST NUMBE
193. hat all files have read permission Date and Time Routines Various date and time routines are available to determine system time or convert it to local time Greenwich Mean Time arrays of date and time elements or an ASCII character string DATE and TIME are available as either a function or subroutine Because of the name duplication if your programs do not include the USE IFPORT statement each separately compiled program unit can use only one of these versions For 230 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications example if a program calls the subroutine TIME once it cannot also use TIME as a function Standard Fortran 95 90 includes date and time intrinsic subroutines Error Handling Routines Error handling routines detect and report errors IERRNO error codes are analogous to errno on UNIX systems The IFPORT module provides parameter definitions for many of UNIX s errno names found typically in errno h on UNIX systems IERRNO is updated only when an error occurs For example if a call to the GETC function results in an error but two subsequent calls to PUTC succeed a call to IERRNO returns the error for the GETC call Examine IERRNO immediately after returning from one of the portability library routines Other standard Fortran 90 routines might also change the value to an undefined value If your application uses multithreading remember that IERRNO is set on a per
194. he Intel provided 1ibcxa C library dynamically By default the 1ibcxa library is linked dynamically All C related libraries supplied by Intel are linked in dynamically by default This option is useful when you are using the static option and you want to override the effect of the static option for the libcxa library This option has the opposite effect of static libcxa Static libcxa Links the Intel provided 1ibcxa C library statically By default the 1ibcxa library is linked dynamically All C related libraries supplied by Intel are linked in dynamically by default Use this option to link libcxa statically while still allowing the standard libraries to be linked in by the default behavior See also shared libcxa option static Default Off Alternative syntax non_shared Prevents linking with shared libraries so files Miscellaneous Options These options are described in alphabetical order ansi_alias Default ansi_alias Enables the compiler to assume that the program adheres to the Fortran 95 Standard type aliasability rules 62 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications For example an object of type real cannot be accessed as an integer For complete information on the rules for data types and data type constants see Data Types Constants and Variables in the Language Reference The option directs the compiler to assume the follo
195. he file octagon o is then used as input to the 1a command to create the shared library named octagon so ld shared no_archive octagon o lifport lifcoremt limf lm lirc lcxa lunwind lpthread lc Note the following e The sharea option is required to create a shared library e The no_archive option indicates that 1a should not search archive libraries to resolve external names only shared libraries e The name of the object file is octagon o You can specify multiple object ol files e The libport and subsequent options are the standard list of libraries that the ifort command would have otherwise passed to 1a When you create a shared library all symbols must be resolved It is probably a good idea to look at the output of the dryrun command to find the names of all the libraries used so you can specify them correctly You can use the Qoption command to pass options to 1d See also the 1a 1 reference page Shared Library Restrictions When creating a shared library with 1a be aware of the following restrictions 29 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications e Shared libraries must not be linked with archive libraries When creating a shared library you can only depend on other shared libraries for resolving external references If you need to reference a routine that currently resides in an archive library either put that routine in a separate shared librar
196. ibrary routine bt Eh 32 falias compiler option 71 fast compiler option 71 fcode asm comipiler option 82 FDX kevword en 123 ffnalias compiler option 71 FGX keyword ssssssssssssssserernneesse 123 file unlocking RE 138 file access OPEN statement specifiers for 152 file characteristics OPEN statement specifiers for 152 EIER eeneg 141 file close action OPEN statement specifier for 152 file information OPEN statement specifiers for 152 file locations coding in an OPEN statement 152 file name inquiry by vies ove ieee 155 file names default rules for applying 6 149 file organtzaton 142 158 file position OPEN statement specifiers for 152 file processing OPEN statement specifiers for 152 file sharing EE 160 file specification 149 file specifications sssseeeeeeeeeeenne 10 FILE specifier in OPEN statement 147 149 filename extensions 0 9 files ACCESSING E 147 ASSIQNING E 147 de EE 143 Index multiple compiling and linking 16 Opening 152 OUI DEI 10 OVEIMIOW ereescht 141 DrecOopnneched en 147 record overhead 146 record fwvpe 144 ee EE 143 temporary 1 2000 cceseeeeeerceeeeeceneneees 11 FIND statement 00000nnn 138 158 FIORT_CONVERTn environment Te niniin erini 128 fixed compiler option 20 60 fixed format compiler option Tor 60 fixed form Tee
197. ic function results in the execution of the first print statement The table below explains the symbols in the file opt intel_fc_80 include fordef for and their corresponding floating point representations Symbols in File fordef for Symbol Name Class of Floating Point Bit Representation FOR_K_FP_SNAN Signaling NaN FOR_K_FP_QNAN Quiet NaN FOR_K_FP_POS_INF Positive infinity FOR_K_FP_NEG_INF Negative infinity FOR_K_FP_POS_ NORM Positive normalized finite number FOR_K_FP_NEG NORM Negative normalized finite number FOR RER POS _DENORM Positive denormalized number FOR_K_FP_NEG_DENORM Negative denormalized number FOR_K_FP_POS_ZERO Positive zero FOR_K_FP_NEG_ZERO Negative zero Another example of using file fordef for and intrinsic function FP_CLASS follows The goals of this program are to quickly read any 32 bit pattern into a REAL 4 number from an unformatted file with no exception reporting and to replace denormalized numbers with true zero 118 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications include fordef for real 4 a 100 integer 4 class_of_bits open an unformatted file as unit 1 read 1 a do i 1 100 class_of_bits fp_class a i if class_of_bits eg for_k_fp_pos_denorm Or amp class_of_bits eq for_k_fp_neg_denorm then a i 0 0 end if end do close 1 end You can compile this program wi
198. idb run 5 1 stopped at squares f90 4 0x120001a88 gt 8 K 0 idb step 6 stopped at squares 9 0x120001a90 9 Es H I 1p N idb print n k 7 4 0 idb step 8 stopped at squares 10 0x120001ab0 10 F INARR I NE 0 THEN idb s stopped at squares 11 0x12000llacc 11 OUTARR K INARR I 2 idb print i k 9 1 0 idb assign k 1 10 idb watch variable k 11 2 watch variable write k 0x1400002c0 to 0x1400002c3 idb cont 12 Number of nonzero elements is Element 1 has value 4 95 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Process has exited with status 0 idb quit 13 vi squares f90 14 10 F INARR I NE 0 THEN 11 K K 41 Hie OUTARR K INARR I 2 tas ENDIF ifort g o squares squares f90 15 idb squares Welcome to the idb Debugger Version x x xx Reading symbolic information done idb when at 12 print k 16 1 when at squares f90 12 print K idb run 17 1 when squares 12 0x120001ae0 1 when squares 12 0x120001ae0 2 1 when squares 12 0x120001ae0 3 1 when squares 12 0x120001ae0 4 Number of nonzero elements is 4 Element 1 has value 9 Element 2 has value 4 Element 3 has value 25 Element 4 has value 4 Process has exited with status 0 idb quit
199. ies one or more directories to add to the include path which is searched for module files USE statement and include files INCLUDE statement Use a semicolon delimiter for more than one directory To request that the compiler search first in the directory where the source file resides instead of the current directory specify assume source_include For all USE statements and for those INCLUDE statements whose file name does not begin with a device or directory name the directories searched are as follows in this order 1 The directory containing the first source file if assume source_include was specified which is the default 2 The current default directory where the compilation is taking place 3 If specified the directory or directories listed in the Idir option The order of searching multiple directories occurs within the specified list from left to right 4 The directories indicated in the compile time environment variable FPATH See also noinclude preprocess only Default Off Alternate syntax P and F Runs the Fortran preprocessor fpp and puts the result for each source file in a corresponding i or i90 file The i or i90 file does not have line numbers in it The source file is not compiled You need to specify fpp with this option U name Default Off Undefines any definition currently in effect for the symbol specified by name Wp option1 option2 Default Off Passes option
200. ifferences in identifiers and to convert external names touppercase Alternate syntax uppercase e lowercase Causes the compiler to ignore case differences in identifiers and to convert external names to lowercase Alternate syntax Lowercase e as_is Causes the compiler to distinguish case differences in identifiers and to preserve the case of external names Instead of using this option consider using the ALIAS directive for the specific name needed Floating Point Options The floating point options let you specify how you want floating point data to be treated See also Optimization Options Descriptions of Floating Point Options assume no minus0 53 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Default assume nominus0O Tells the compiler to use Fortran 95 standard semantics for the treatment of the IEEE floating point value 0 0 in the SIGN intrinsic if the processor is capable of distinguishing the difference between 0 0 and 0 0 and to write a value of 0 0 with a negative sign on formatted output The default assume nominus0O tells the compiler to use Fortran 90 77 standard semantics in the SIGN intrinsic to treat 0 0 and 0 0 as 0 0 and to write a value of 0 0 with no sign on formatted output no fltconsistency Default nofltconsistency Alternate syntax mp Enables improved floating point consistency during calculations This option lim
201. ified e For certain errors whether or not the default action of an associated signal was changed e For certain errors related to arithmetic operations including floating point exceptions compilation options can determine whether the error is reported and the severity of the reported error How arithmetic exception conditions are reported and handled depends on the cause of the exception and how the program was compiled Unless the program was compiled to handle exceptions the exception might not be reported until after the instruction that caused the exception condition The following compiler options are related to handling errors and exceptions e The check bounds option generates extra code to catch certain conditions e The check noformat and check nooutput_conversion options reduce the severity level of the associated run time error to allow program continuation e The fpen options control the handling and reporting of floating point arithmetic exceptions at run time e The warn xxxx u nowarn w and w1 options control compile time warning messages which in some circumstances can help determine the cause of a run time error 216 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Run Time Message Format When errors occur during execution run time of a program the Fortran RTL issues diagnostic messages These run time messages have the following format forrtl severit
202. ifiers for File and Unit Information cceeeeeeeeeeeeeeeeeeeeeeeeeeeneeeeeeees 151 Specifiers for File and Record Characteristics ccccceeeeeseeeseteeeeeeees 151 Specifier for Special File Open Routine EE 152 Specifiers for File Access Processing and Position sssessessserrenneeesn 152 Specifiers for Record Transfer Characteristics ccccceceeeeeeeeeeeeeeeeeeees 152 Specifiers for Error Handling Capabilities ceeeeceeeeeeeeeeeeeeeeenneeeeeeeees 152 Specifier for File Close Achon EE 152 Coding File Locations in an OPEN Giatement 153 Obtaining File Information INQUIRE Giatement 153 Fave Wie alos la 153 Inquiry by File EE 154 Inquiry by Output ltem List E 155 Closing a File CLOSE Gtatement EEN 155 Record Operations Overview EEN 156 Record UO Statement Specifier AEN 156 ee Ee 157 EE ACCESS eege 157 KIT ee 158 Limitations of Record Access by File Organization and Record Type 158 PUG SSM dn DEE 159 specifying the Initial Record POSIIOMsccisceiccacccticeescoiteeiienlaniitenisedeielgnetiotiteensd 159 Advancing and Nonadvancing Record WO 160 Table Of Contents tele Rn EE 161 Input Record Transfer ets seat Sts Ste at Sts Mi ts Sala Nr ls te le a cae le ennn 161 Output Record WE E 162 User Supplied OPEN Procedures USEROPEN Specifier AA 163 Syntax and Behavior of the USEROPEN Specifier AAA 163 Restrictions of Called USEROPEN Functions ssseeeeeeeeeeeeeeer
203. ify that option after the fast option on the command line Note The several options set by the fast option might change from release to release fnsplit Itanium based systems only Default Off Enables function splitting if prof_use is also enabled This option has no effect if prof_use is not enabled This option is automatically enabled if you use prof_use To turn off function splitting use fnsplit However function grouping will continue to be enabled See also these topics in Volume II Basic PGO Options Example of Profile Guided Optimization fp IA 32 systems only Default On Disables the use of ebp as a general purpose register Most debuggers expect ebp to be used as a stack frame pointer and cannot produce a stack backtrace unless this is so This option allows frame pointers and disables the use of the ebp register in optimizations and lets the debugger produce a stack backtrace gp Default Off 72 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Alternate syntax p Compile and link for function profiling with the gprof tool ip Default Off Enables single file interprocedural optimizations Enhances inline function expansion See also this topic in Volume II Using ip with option Specifiers ip_no_inlining Default Off Disables interprocedural inlining that results from the ip or ipo interprocedural optimization
204. ig endian IEEE format to native little endian IEEE memory format when read from unit 28 and then written without conversion in native little endian IEEE format to unit 29 Without requiring source code modification or recompilation of this program the following command sequence sets the appropriate environment variables before running the program usr users leslie convieee setenv FORT_CONVERT28 BIG _ENDIAN setenv FORT_CONVERT29 NATIVE usr users leslie convieee The following figure shows the data formats used on disk and in memory when the example file usr users leslie convieee is run after the environment variables are set Sample Unformatted File Conversion 127 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Native Memory Formats Little Endian Integers and Little Endian IEEE 3 ost and T_float Formats ee aes Unit 28 Do Not Convert SCH Convert to Write Native Memory Formats Native Formats Little Endian IEEE Unformatted Data Files on Disk Deeg This method takes precedence over other methods 2K 83264 GE Environment Variable FORT CONVERT ext or FORT CONVERT ext Method You can use this method to specify a non native numeric format for each specified file name extension suffix You specify the numeric format at run time by setting the appropriate environment variable before an implicit or explicit OPEN to one or more unformatted f
205. ile that was locked by a previous READ statement ACCEPT Reads input from stdin Unlike READ ACCEPT only provides formatted sequential input and does not specify a unit number Record output WRITE Transfers data from internal storage to an external file record or to an internal file 137 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications REWRITE Transfers data from internal storage to an external file record at the current record position direct access relative files only TYPE Writes record output to stdout Same as PRINT PRINT Transfers data from internal storage to stdout Unlike WRITE PRINT only provides formatted sequential output and does not specify a unit number In addition to the READ WRITE REWRITE TYPE and PRINT statements other I O record related statements are limited to a specific file organization For instance e The DELETE statement only applies to relative files Detecting deleted records is only available if the vms option was specified when the program was compiled e The BACKSPACE statement only applies to sequential files open for sequential access e The REWIND statement only applies to sequential files open for sequential access and to direct access files e The ENDFILE statement only applies to certain types of sequential files open for sequential access and to direct access files e The UNLOCK statement only ap
206. iles You can use the format FORT_CONVERT ext or FORT_CONVERT_ ext where ext is the file extension or suffix The FORT_CONVERT ext environment variable is checked before FORT_CONVERT_ ext environment variable if extis the same For example assume you have a previously compiled program that reads numeric data from one file and writes to another file using unformatted I O statements You want the program to read nonnative big endian IEEE floating point format from a file with a dat file extension extension and write that data in native little endian format to a file with a extension of data In this case the data is converted from big endian IEEE format to native little endian IEEE memory format S_float and T_float when read from file dat and then written without conversion in native little endian IEEE format to the file with a suffix of data assuming that environment variables FORT _CONVERT DATA and FORT_CONVERTn for that unit number are not defined Without requiring source code modification or recompilation of this program the following command sequence sets the appropriate environment variables before running the program setenv FORT_CONVERT DAT BIG_ENDIAN usr users proj2 cvbigend 128 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications The FORT_CONVERTn method takes precedence over this method When the appropriate environment variable is set when you open the file the F
207. in I O statements to transfer control to a specified point in the program e The END branch specifier handles an end of file condition e The EOR branch specifier handles an end of record condition for nonadvancing reads e The ERR branch specifier handles all error conditions If you use the END EOR or ERR branch specifiers no error message is displayed and execution continues at the designated statement usually an error handling routine You might encounter an unexpected error that the error handling routine cannot handle In this case do one of the following e Modify the error handling routine to display the error message number e Remove the END EOR or ERR branch specifiers from the I O statement that causes the error After you modify the source code compile link and run the program to display the error message For example READ 8 50 ERR 400 If any severe error occurs during execution of this statement the Intel Fortran RTL transfers control to the statement at label 400 Similarly you can use the END specifier to handle an end of file condition that might otherwise be treated as an error For example READ 12 70 END 550 When using nonadvancing I O use the EOR specifier to handle the end of record condition For example 150 FORMAT F10 2 F10 2 I6 READ UNIT 20 FMT 150 SIZE X ADVANCE NO EOR 700 A F You can also use ERR as a specifier in an OPEN CLOSE o
208. ing of signals e As with other debugging tasks use the g option to generate sufficient symbol table information and debug unoptimized code If requested idb will catch and handle signals before the Intel Fortran run time library RTL does You can use the idb commands catch and ignore to control whether idb catches signals or ignores them e When idb catches a sigOnal an idb message is displayed and execution stops at that statement line The error handling routines provided by the RTL are not called At this point you can examine variables and determine where in the program the signal has occurred e When idb ignores a signal the signal is passed to the RTL This allows the handling and display of run time signal messages in the manner requested during compilation 106 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications To obtain the appropriate run time error message when debugging a program that generates a signal especially one that allows program continuation you might need to use the ignore command before running the program For instance use the following command to tell the debugger to ignore floating point signals and pass them through to the RTL idb ignore fpe In cases where you need to locate the part of the program causing a signal consider using the where command Belle aE RELE Unaligned data can slow program execution You should determine the cause of the unaligne
209. iple bytes as follows e Little endian storage occurs when o The least significant bit LSB value is in the byte with the lowest address o The most significant bit MSB value is in the byte with the highest address o The address of the numeric value is the byte containing the LSB Subsequent bytes with higher addresses contain more significant bits e Big endian storage occurs when o The least significant bit LSB value is in the byte with the highest address o The most significant bit MSB value is in the byte with the lowest address o The address of the numeric value is the byte containing the MSB Subsequent bytes with higher addresses contain less significant bits The following figure shows the difference between the two byte ordering schemes Little and Big Endian Storage of an INTEGER Value 122 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications m L 5 5 B E Byte Order bonaenzhannaasnhkaaneaeahzaaanen Byte Order OOOO TIOoOo tooo oootoooidiidgioodod 1003 1002 1001 1000 M L 3 5 S B Bute Omer 2feteertootocerlooeroecrfieroees Byte Order COOOL tooo ooo ooo diidkioodod 1000 1001 1002 1003 ZK 66544 GE Moving unformatted data files between big endian and little endian computers requires that the data be converted Intel Fortran provides the capability for programs to read and write unformatted data originally written using unformatted I O statements in several
210. is not exact 144 severe 144 reserved operand FOR IOS_ROPRAND The Intel Fortran RTL encountered a reserved operand Please report the problem to Intel 145 severe 145 Assertion error FOR IOS_ASSERTERR The Intel Fortran RTL encountered an assertion error Please report the problem to Intel 146 severe 146 Null pointer error 254 FOR IOS_NULPTRERR Attempted to use a pointer that Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications does not contain an address Modify the source program recompile and relink 147 severe 147 stack overflow FOR IOS_STKOVF The Intel Fortran RTL encountered a stack overflow while executing your program 148 severe 148 String length error FOR IOS_STRLENERR During a string operation an integer value appears in a context where the value of the integer is outside the permissible string length range Either recompile with the check bounds option perhaps with the decfort_dump_flag environment variable set or examine the core file to determine the source code causing the error 149 severe 149 Substring error FOR IOS_SUBSTRERR An array subscript is outside the dimensioned boundaries of an array Either recompile with the check bounds option perhaps with the decfort_dump_flag environment variable set or examine the core file to determine the source code causing the error 150 severe 150 Range error FOR IOS_
211. it numbers you cannot read data in one format and write it in another format unless you use it in combination with one of the environment variable methods or the OPEN statement CONVERT keyword method to specify a different format for a particular unit number Compiler Option convert Method You can only specify one numeric format for all unformatted file unit numbers using the compiler option convert method unless you also use one or more of the previous methods You specify the numeric format at compile time and must compile all routines under the same convert keyword compiler option You could use the same source program and compile it using different i fort commands to create multiple executable programs that each read a certain format If you specify other methods they take precedence over this method For instance you might use the environment variable or OPEN statement CONVERT keyword method to specify each unit number that will use a format different than that specified using the convert keyword compiler option method for all other unit numbers For example the following command compiles program file for to use VAX D_floating and F_floating floating point data for all unit numbers unless superseded by one of the other methods Data is converted between the file format and the little endian memory format little endian integers S_float and T_float little endian IEEE floating point format The created file vconvert exe
212. ith no arguments will report your current settings and limit coredumpsize unlimited will raise the allowable limit to your current system maximum Handling Run Time Errors Whenever possible the Intel Fortran RTL does certain error handling such as generating appropriate messages and taking necessary action to recover from errors You can explicitly supplement or override default actions by using the following methods e To transfer control to error handling code within the program use the ERR EOR and END branch specifiers in I O statements e To identify Fortran specific I O errors based on the value of Intel Fortran RTL error codes use the I O status specifier IOSTAT in I O statements or call the ERRSNS subroutine e Obtain system level error codes by using the appropriate library routines e For certain error conditions use the signal handling facility to change the default action to be taken These error processing methods are complementary you can use any or all of them within the same program to obtain Intel Fortran run time and Linux system error codes Using the END EOR and ERR Branch Specifiers 220 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications When a severe error occurs during Intel Fortran program execution the default action is to display an error message and terminate the program To override this default action there are three branch specifiers you can use
213. its floating point optimizations and maintains declared precision Floating point operations are not reordered and the result of each floating point operation is stored into the target variable rather than being kept in the floating point processor for use in a subsequent calculation For example the compiler can change floating point division computations into multiplication by the reciprocal of the denominator This change can alter the results of floating point division computations slightly The default value nofltconsistency provides better accuracy and run time performance at the expense of less consistent floating point results This option might slightly reduce execution speed See also Improving Restricting FP Arithmetic Precision in Volume II Optimizing Applications fp_port IA 32 systems only Default Off Rounds floating point results after floating point operations so rounding to user declared precision happens at assignments and type conversions this has some impact on speed 54 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications The default is to keep results of floating point operations in higher precision this provides better performance but less consistent floating point results See also Floating Point Arithmetic Precision for 1A 32 Systems in Volume II Optimizing Applications no fpconstant Default nofpconstant Requests that a single precision consta
214. its for conversion purposes on these units the input output operations perform big little endian conversion 5 Assume you set F_UFMTENDIAN 10 100 and run the following program integer 4 cc4 integer 8 cc8 integer 4 c4 integer 8 c8 c4 456 c8 789 C prepare little endian representation of data open 11 file lit tmp form unformatted write 11 c8 write 11 c4 close 11 C prepare big endian representation of data open 10 file big tmp form unformatted 131 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications write 10 c8 write 10 c4 close 10 C read big endian data and operate with them on C little endian machine open 100 file big tmp form unformatted read 100 cc8 read 100 cc4 CG Any operation with data which have been read e Sp close 100 stop end Now compare lit tmp and big tmp files with the help of od utility t x4 lit tmp 000 00000008 00000315 00000000 00000008 020 00000004 000001c8 00000004 034 Coe SY ooo O 0 0 0 t x4 big tmp 000 08000000 00000000 15030000 08000000 020 04000000 c8010000 04000000 034 gt 0 0 0 You can see that the byte order is different in these files OPEN Statement CONVERT Method COOC 0 O 0 0 0 O O O You can use this method to specify a non native numeric format for each specified unit
215. k the statement containing xx a character substring from the format string for a format 249 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications syntax error For information about FORMAT statements see the nte Fortran Language Reference Manual 5Qsevere 59 List directed I O syntax error FOR IOS_LISIO_SYN The data in a list directed input record had an invalid format or the type of the constant was incompatible with the corresponding variable The value of the variable was unchanged 6Osevere 60 Infinite format loop FOR IOS_INFFORLOO The format associated with an I O statement that included an I O list had no field descriptors to use in transferring those values 61 severe or info 61 Format variable type mismatch FOR IOS_FORVARMIS An attempt was made either to read or write a real variable with an integer field descriptor I L O Z B or to read or write an integer or logical variable with a real field descriptor D E or F 62severe 62 Syntax error in format FOR IOS_SYNERRFOR A syntax error was encountered while the RTL was processing a format stored in an array or character variable 63error or info 63 Output conversion error FOR IOS_OUTCONERR During a formatted output operation the value of a particular number could not be output in the specified field length without loss of significant digits When this situation is encountered the overf
216. l warn errors Of warn all warn stderrors Specifying warn Is the same as specifying warn all Specifying nowarn is the same as specifying warn none warn noJalignments Default warn alignments Issues warning messages for data that is not naturally aligned warn no declarations Default warn nodeclarations Issues an error message for any undeclared symbols This option makes the default type of a variable undefined IMPLICIT NONE rather than using the implicit Fortran rules See also u warn noJerrors Default warn noerrors Treats all warnings as errors by changing the severity of all warning diagnostics into error diagnostics including standards warnings warn no general 43 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Default warn general Alternate syntax w1 to display all warnings or w0 or to suppress all warnings Displays all informational level and warning level diagnostic messages from the compiler Use warn nogeneral Of nowarn or H or w to suppress all warnings warn no Jignore_loc Default warn noignore_loc Issues warning messages when LOC is stripped from an argument warn no stderrors Default warn nostderrors Treats warnings about Fortran standards violations as errors not warnings Specifying warn stderrors sets stand f95 If you want to make Fortran 90 standards violations become errors set this option as we
217. l Fortran determines file name and the directory path based on certain rules It determines a file name string as follows e lf the FILE specifier is present its value is used e Ifthe FILE specifier is not present Intel Fortran examines the corresponding environment variable If the corresponding environment variable is set that value is used If the corresponding environment variable is not set a file name in the form fort n is used Once Intel Fortran determines the resulting file name string it determines the directory which optionally precedes the file name as follows 149 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications e If the resulting file name string contains an absolute pathname it is used and the DEFAULTFILE specifier environment variable and current directory values are ignored e Ifthe resulting file name string does not contain an absolute pathname Intel Fortran examines the DEFAULTFILE specifier and current directory value If the corresponding environment variable is set and specifies an absolute pathname that value is used Otherwise the DEFAULTFILE specifier value if present is used If the DEFAULTFILE specifier is not present Intel Fortran uses the current directory as an absolute pathname Using Preconnected Standard UC Files If you do not use an OPEN statement to open logical unit 5 6 or 0 and do not set the appropriate environment variable FORT n
218. l_fc_80 bin File Description codecov Executable for the Code coverage tool fortcom Executable used by the compiler fpp Fortran Preprocessor ifc For compatibility with previous releases ifc cfg For compatibility with previous releases ifort Intel Fortran Compiler Version 8 ifortbin Executable used by the compiler ifort cfg Configuration file ifortvars csh Setup file for C shell ifortvars sh Setup file for bash shell profmerge Utility used for Profile Guided Optimizations proforder Utility used for Profile Guided Optimizations tselect Test prioritization tool uninstall sh Uninstall utility xiar Tool used for Interprocedural Optimizations xild Tool used for Interprocedural Optimizations For a list of the files installed in 1ib see Libraries Provided by Intel Fortran Key Itanium Based Compiler Files Summary The following table shows files that are installed for use by the Itanium based compiler in opt intel_fc_80 bin File Description codecov Executable for the Code coverage tool efc For compatibility with previous releases efc cfg For compatibility with previous releases efcbin For compatibility with previous releases fortcom Executable used by the compiler fpp Fortran Preprocessor ias Intel assembler ifort Intel Fortran Compiler Version 8 ifort cfg Configuration file 236 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building ifortbin ifortvars csh Setup file for C shell ifort
219. laring it as global or COMMON in one language and accessing it as an external variable in the other language In Fortran programs variables must be passed as arguments In Fortran a variable can access a global parameter by using the EXTERN option for ATTRIBUTES For example DEC ATTRIBUTES 2 C EXTERN idata INTEGER idata 20 0 193 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications EXTERN tells the compiler that the variable is actually defined and declared global in another source file If Fortran declares a variable external with EXTERN the language it shares the variable with must declare the variable global In C a variable is declared global with the statement int idata 20 declared as global outside of any function Fortran can declare the variable global COMMON and other languages can reference it as external Fortran declaring PI global REAL PI COMMON PI PI Common Block and variable have the same nam In C the variable is referenced as an external with the statement C code with external reference to PIO extern float PI Note that the global name C references is the name of the Fortran common block not the name of a variable within a common block Thus you cannot use blank common to make data accessible between C and Fortran In the preceding example the common block and the variable have the same name
220. le The text string you assign for the file name is used literally so you must specify the full name If the file open fails no error is reported and the run time system continues diagnostic processing e FOR_DISABLE_DIAGNOSTIC_DISPLAY Disables the display of all error information This variable is helpful if you just want to test the error status of your 233 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications program and do not want the Fortran run time system to display any information about an abnormal program termination e FOR_DISABLE_STACK_TRACE This variable disables the call stack trace information that follows the displayed severe error message text The Fortran run time error message is displayed whether or not FOR_DISABLE_STACK_TRACE is set to true e FOR_IGNORE_EXCEPTIONS This variable disables the default run time exception handling for example to allow just in time debugging The run time system exception handler returns EXCEPTION CONTINUE SEARCH to the operating system which looks for other handlers to service the exception e FOR_NOERROR_DIALOGS This variable disables the display of dialog boxes when certain exceptions or errors occur This is useful when running many test programs in batch mode to prevent a failure from stopping execution of the entire test stream e FOR_PRIN
221. le name of the first Fortran file on the command line is used to create the file name of the so file You can specify additional options associated with shared library creation e f you specify the c option you will create an object file o file that you can name with the o option To create a shared library process the o file with 1a specifying certain options associated with shared library creation e When building shared libraries on Itanium based systems you must specify the fpic option for the compilation of each object file included in the shared library If this option is not used the linker will probably emit an error message like gprel relocation against dynamic symbol Creating a Shared Library with a Single ifort Command You can create a shared library so file with a single ifort Command ifort shared octagon f90 28 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications The sharea option is required to create a shared library The name of the source file is octagon 90 You can specify multiple source files and object files The o option was omitted so the name of the shared library file is octagon so Since you omitted the c option you do not need to specify the standard list of Fortran libraries Creating a Shared Library with ifort and Id Commands You first must create the o file such as octagon o in the following example ifort c octagon f90 T
222. lei le EE 61 AMO SUCHIN enen a a a a Eoee tes Te Eene ea a eee eee 61 SE E 61 Sale E leie 62 SE lee e EE 62 SSL ANIC EAEE ENEN 62 Miscellaneous ODUONS ee alae ieee 62 PANS NANA E EE 62 ASSUME COMOMD panniers A A 63 ASSUME ION eege eege enden a ana 63 STEE ees 63 ccdefault keyword EE 64 SEITEN 64 SEO lat 64 elle Ge ae Goce mere pene nner eer erp parece ee rE ean arene oe een 64 fvisibility keyword and fvisibility Keyword file ceeeeeeeeeeeeeeeeeeeeees 64 eg DEE 65 aS E 65 SUN MUN 5AM ACP SUNN Os sian ea nea nna a na ns a we eS 65 viii Table Of Contents MOOG O nett tats ctr tet ae ete at ete it tle ils tee eee 65 SEH EMMA eas eae rt ac a are ee a ee ee 66 nelle LEE 66 S O AG EE 66 prec_div IA 32 systems only seen 66 shed lAe32 System S OMY cdasasevacete reve a aa e dex etude ead e cette iaaa aa en vss 67 size_ p64 Itanium based systems on 67 TO StACK TOMS os o 5 sees cvareea a aa aa a a N A i a 67 SEENEN ENEE 67 SEL SONUY AE EE A E A EE 67 e Er 67 SEH 68 SU E A 68 Vae a A 68 AT AT EE E E ESE ESEESE EE 68 CO DTE EE 68 e t et tele SODHON 2 enaa A nee ee EEEa 68 EE ili OU IU Nai SUA Sai aS 69 Xlinker ET 69 Optimization OpPtONS essa cece cc corset tek pace tee tak Uae cet tema aaRS 69 Descriptions of Optimization Options EE 69 assume no buffered_io E 69 auto_ilp32 Itanium based systems only eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 70 Table Of Contents ax K W N B
223. lents in standard Fortran 95 90 Data object conversion can be accomplished by using the INT intrinsic function instead of LONG or SHORT The intrinsic subroutines RANDOM_NUMBER and RANDOM_SEED perform the same functions as the random number functions listed in the table showing numeric values and conversion routines Other bit manipulation functions such as AND XOR OR LSHIFT and RSHIFT are intrinsic functions You do not need the IFPORT module to access them Standard Fortran 95 90 includes many bit operation routines These routines are listed in Chapter 9 of the Language Reference in table 9 2 under Category Bit Input and Output Routines The portability library contains routines that change file properties read and write characters and buffers and change the offset position in a file These input and output routines can be used with standard Fortran input or output statements 229 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications such as READ or WRITE on the same files provided that you take into account the following e When used with direct files after an FSEEK GETC or PUTC operation the record number is the number of the next whole record Any subsequent normal Fortran UO to that unit occurs at the next whole record For example if you seek to absolute location 1 of a file whose record length is 10 the NEXTREC returned by an INQUIRE would be 2 If you seek to absolute location 10
224. les of Compiler Options Some options consist of two words separated by a space while others may have words joined by an underscore _ Most options can be abbreviated usually to four characters or more For example you can abbreviate check output_conversion to check out Intel Fortran has four styles of compiler options e The phrase no precedes the option to disable it This style was used in Compaq Fortran Example logo and nologo e A hyphen following the option disables it This style was used in previous Intel Fortran compilers Example prefetch and prefetch e Ano orno in the middle of the option disables it Example falias and fno alias e The option has an n parameter specifying a number and is disabled by setting n equal to 0 s Note If there are enabling and disabling versions of options on the command line or two versions of the same option the last one takes precedence Using Multiple ifort Commands 33 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications If you compile parts of your program by using multiple ifort commands options that affect the execution of the program should be used consistently for all compilations especially if data is shared or passed between procedures For example e The same data alignment needs to be used for data passed or shared by module definition such as user defined structures or common block Use the same version of the
225. ll as stand 90 warn no truncated_source Default warn notruncated_source Issues warning messages when reading a source line with a statement field that exceeds the maximum column width in fixed format source files The maximum column width for fixed format files is 72 80 or 132 depending on the setting of the extend_source option The warn truncated_source option has no effect on truncation lines that exceed the maximum column width are always truncated The warn truncated_source option does not apply to free format source files warn no Juncalled Default warn uncalled Issues warning messages when a statement function is never called 44 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications warn no Junused Default warn nounused Issues warning messages for variables that are declared but never used warn no usage Default warn usage Alternate syntax cm which is equivalent to warn nousage Suppresses messages about questionable programming practices Questionable programming practices although allowed often are the result of programming errors For example the default value warn usage detects a continued character or Hollerith literal whose first part ends before the statement field ends and appears to end with trailing spaces Data Options The data options let you specify rules for how your Fortran data is treated by the compiler optimizer and code ge
226. lock IF statement nesting 128 combined DO loop index variable 9 223 372 036 854 7 75 807 2 63 237 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications 1 Format group nesting 8 Format statement length 2048 characters Fortran source line length fixed form 72 or 132 if extend_source is in effect characters free form 7200 characters INCLUDE file nesting 20 levels Labels in computed or assigned GOTO Limited only by memory constraints list Lexical tokens per statement 20000 Named common blocks Limited only by memory constraints Nesting of array constructor implied 7 DOs Nesting of input output implied DOs 7 Nesting of interface blocks Limited only by memory constraints Nesting of DO IF or CASE constructs Limited only by memory constraints Nesting of parenthesized formats Limited only by memory constraints Number of digits in a numeric constant Limited only by memory constraints Parentheses nesting in expressions Limited only by memory constraints Structure nesting 30 Symbolic name length 63 characters See the product Release Notes for more information on memory limits for large data objects Hexadecimal Binary Octal Decimal Conversions The following table lists hexadecimal binary octal and decimal conversion Hex Number Binary Number Octal Number Decimal Number 0 0000 00 0
227. long double complex Expressions in Debugger Commands 104 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Expressions in debugger commands use Fortran 95 90 source language syntax for operators and expressions Enclose debugger command expressions between curly braces For example the expression print xk in the following statement is enclosed between curly braces idb when at 12 print k Fortran Operators The Intel Fortran operators include the following e Relational operators such as less than LT or lt and equal to EQ or e Logical operators such as logical conjunction AND and logical disjunction OR e Arithmetic operators including addition subtraction multiplication and division For a complete list of operators see the Intel Fortran Language Reference Manual Procedures The idb debugger supports invocation of user defined specific procedures using Fortran 95 90 source language syntax See Also Intel Fortran Language Reference Manual Online Inte Debugger IDB Manual Debugging Mixed Language Programs The idb debugger lets you debug mixed language programs Program flow of control across subprograms written in different languages is transparent The debugger automatically identifies the language of the current subprogram or code segment on the basis of information embedded in the executable file For
228. lowed field is filled with asterisks to indicate the error in the output record If no ERR address has been defined for this error the program continues after the error message is displayed 64severe 64 Input conversion error FOR IOS_INPCONERR During a formatted input operation an invalid character was detected in an input field or the input value overflowed the range representable in the input variable The value of the variable was set to zero 65error 65 Floating invalid FOR IOS_FLTINV During an arithmetic operation the floating point values used in a calculation were invalid for the type of operation requested or invalid exceptional 250 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications values For example when requesting a log of the floating point values 0 0 or a negative number For certain arithmetic expressions specifying the check nopower option can suppress this message 66 severe 66 Output statement overflows record FOR IOS_OUTSTAOVE An output statement attempted to transfer more data than would fit in the maximum record size 67 severe 67 Input statement requires too much data FOR IOS_INPSTAREQ Attempted to read more data than exists in a record with an unformatted READ statement or with a formatted sequential READ statement from a file opened with a PAD specifier value of NO 68 severe 68 Variable format expression value error FOR
229. lts to determine the record type The default record type RECORDTYPE with Intel Fortran depends on the values for the ACCESS and FORM specifiers for the OPEN statement e Certain vendors use a different identifier for the logical data types such as hex FF instead of 01 to denote true e Source code being ported may be coded specifically for big endian use Fortran I O Fortran I O Overview See these topics Logical I O Units Types of I O Statements Forms of I O Statements Files and File Characteristics Overview Accessing and Assigning Files Default Pathnames and File Names Using Preconnected Standard I O Files Opening Files OPEN Statement 135 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Obtaining File Information INQUIRE Statement Closing a File CLOSE Statement Record Operations Overview User Supplied OPEN Procedures USEROPEN Specifier Format of Record Types Logical I O Units In Intel Fortran a logical unitis a channel through which data transfer occurs between the program and a device or file You identify each logical unit with a logical unit number which can be any nonnegative integer from 0 to a maximum value of 2 147 483 647 2 31 1 For example READ 2 100 I X Y This READ statement specifies that data is to be entered from the device or file corresponding to logical unit 2 in the format specified by the FORMAT statement labeled 100
230. lue values passed or by reference addresses passed Individual Fortran arguments can also be designated with ATTRIBUTES option VALUE or REFERENCE 4 The caller routine and the called routine use a calling convention to establish naming conventions for procedure names You can establish any procedure name you want regardless of its Fortran name with the ALIAS directive or 181 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications ATTRIBUTES option ALIAS This is useful because C is case sensitive while Fortran is not See these topics ATTRIBUTES Properties and Calling Conventions Fortran C Calling Conventions ATTRIBUTES Properties and Calling Conventions The ATTRIBUTES properties also known as options C REFERENCE VALUE and VARYING all affect the calling convention of routines You can specify the e C REFERENCE and VARYING properties for an entire routine e VALUE and REFERENCE properties for individual arguments By default Fortran passes all data by reference except the hidden length argument of strings which is passed by value If the C property is used the default changes to passing almost all data except arrays by value However in addition to the calling convention property C you can specify argument properties VALUE and REFERENCE to pass arguments by value or by reference regardless of the calling convention property Arrays can only be passed by reference
231. me for_msg cat The Intel Fortran message catalog file was not found See Message Catalog File Location This error has no condition symbol None Insufficient memory to open Fortran RTL catalog message 41 The Intel Fortran message catalog file could not be opened because of insufficient virtual memory To overcome this problem increase the per process data limit by using the limit C shell or ulimit Bourne and Korn and bash shells commands before running the program again For more information see error 41 This error has no condition symbol 1 severe 1 Not a Fortran specific error FOR IOS_NOTFORSPE An error in the user program or in the RTL was not a Intel Fortran specific error and was not reportable through any other Intel Fortran run time messages If you call ERRSNS an error of this kind returns a value of 1 for more information on the ERRSNS subroutine see the nte Fortran Language Reference Manual Qsevere 8 Internal consistency check failure FOR IOS_BUG_CHECK Internal error Please check that the program is correct Recompile if an error existed in the program If this error persists submit a problem report Qsevere 9 Permission to access file denied FOR IOS_PERACCFIL Check the mode protection of the specified file Make sure the correct file was being accessed Change the protection specified file or process used before rerunning program 10 severe 10 Cannot overwrite existing file
232. me that contains both a directory and file name Using Environment Variables You can use shell commands to set the appropriate environment variable to a value that indicates a directory if needed and a file name to associate a unit with an external file Intel Fortran recognizes environment variables for each logical I O unit number in the form of FORTn where n is the logical I O unit number If a file name is not specified in the OPEN statement and the corresponding FORTn environment variable is not set for that unit number Intel Fortran generates a file name in the form fort n where n is the logical unit number Implied Intel Fortran Logical Unit Numbers 147 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications The ACCEPT PRINT and TYPE statements and the use of an asterisk in place of a unit number in READ and WRITE statements do not include an explicit logical unit number Each of these Fortran statements uses an implicit internal logical unit number and environment variable Each environment variable is in turn associated by default with one of the Fortran file names that are associated with standard I O files The table below shows these relationships Intel Fortran Environment Environment Standard I O file statement variable when variable when name vms specified vms omitted READ f iolist FOR_READ FORTS stdin READ f iolist FOR_READ FORTS
233. mp none Default fpscomp libs Specifies that all the fpscomp options for compatibility with Microsoft Fortran PowerStation should be used The default value specifies that the PowerStation portability library should be passed to the linker fpscomp none specifies that no options for Fortran PowerStation compatibility should be used fpscomp no filesfromcmd Default fpscomp nofilesfromcmd Specifies Microsoft Fortran PowerStation behavior when the OPEN statement file specifier is blank This option looks in the command line arguments for unspecified filenames on an OPEN FILE and prompts for filenames at the terminal console fpscomp no general Default foscomp nogeneral Specifies that Microsoft Fortran PowerStation semantics should be used where differences exist between Intel Fortran and PowerStation fpscomp no ioformat Default fpscomp noioformat Specifies Microsoft Fortran PowerStation semantic conventions and record formats for list directed formatted I O and unformatted I O fpscomp no libs 38 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Default fpscomp libs Specifies that the PowerStation portability library should be passed to the linker fpscomp no logicals Default foscomp nologicals Specifies that Microsoft Fortran PowerStation representation of LOGICAL values will be used prof_format_32 Default Off Produces
234. ms in the I O statement and its associated format specifier jointly determine the amount of data to be transferred e With namelist and list directed output the items listed in the NAMELIST statement or I O statement list in conjunction with the NAMELIST or list directed formatting rules determine the amount of data to be transferred e With unformatted I O except for fixed length records the I O statement alone specifies the amount of data to be transferred e When you specify fixed length records RECORDTYPE FIXED all records are the same size If the size of an I O record being written is less than the record length RECL extra bytes are added padding Typically the data transferred by an I O statement is read from or written to a single record It is possible however for a single I O statement to transfer data from or to more than one record depending on the form of I O used Input Record Transfer 161 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications When using advancing UO if an input statement specifies fewer data fields less data than the record contains the remaining fields are ignored If an input statement specifies more data fields than the record contains one of the following occurs e For formatted input using advancing UC if the file was opened with PAD YES additional fields are read as spaces If the file is opened with PAD NO an error occurs the
235. must be established for naming variables and procedures for stack use and for argument passing among routines written in different languages These rules as a whole are the calling convention A calling convention includes e Stack consideration Does a routine receive a varying or fixed number of arguments e Naming conventions o Is lowercase or uppercase significant or not significant o Are external names altered e Argument passing protocol o Are arguments passed by value or by reference o What are the equivalent data types and data structures among languages This section provides information on the calling conventions available when writing routines written in Fortran C C and assembly language See these topics Calling Subprograms from the Main Program Summary of Mixed Language Issues Adjusting Calling Conventions in Mixed Language Programming Overview Adjusting Naming Conventions in Mixed Language Programming Overview Protoyping a Procedure in Fortran Exchanging and Accessing Data in Mixed Language Programming Overview Handling Data Types in Mixed Language Programming Overview Intel Fortran C Mixed Language Programs Overview Calling Subprograms from the Main Program Calls from the Main Program 178 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications The Intel Fortran main program can call Intel Fortran subprograms including subprograms in static and shared libraries F
236. n 64 CODECS DICH EE 36 COIR DS prefix EE 36 Cell number EN 142 Character array seeeeseeeeeeee 143 character array element 143 character array section 143 264 character data representation 121 character data types retUrnINg staves tease E 209 character strings handling stent eett Vol a 209 character subeirimg 143 character varable 143 check ompiler option 86 checking run time EE 86 CLOSE statement 138 157 closing a file See CLOSE statement 157 code generation options 37 codecov file a an 237 238 Code coverage tool 237 238 command line output redirecting Ae 27 commands debugger expressions In 106 SUMIMALY OF cpisceiserice eeeinieets 93 OG DUGG CF EE 91 common block variable 99 common blocks allocating Scie iets aie 32 passing the address of 194 using in mixed language Drogramming 194 common external data structures 194 common_args compiler option 47 compatibility with Microsoft Fortran PowerStation ccccee 174 compatibility opttons 38 compatibility with previous versions esbaeekebekach eet ey aoe eege 240 compilation diagnostics options 42 compilation phases eseseeeeeeenn 6 compilation process COMMONING BE 13 compiler Component Of 2 default behavior of 8 INVOKING ictcsi helene ckesteh teeta 14 EE 1
237. n Data and UO Data Representation Data Representation Overview See these topics Intrinsic Data Types Integer Data Representations Overview Logical Data Representations Native IEEE Floating Point Representations Overview Character Representation Hollerith Representation Intrinsic Data Types Intel Fortran expects numeric data to be in native little endian order in which the least significant right most zero bit bit 0 or byte has a lower address than the most significant left most bit or byte For information on using nonnative big endian and VAX floating point formats see Converting Unformatted Numeric Data The symbol A in any figure specifies the address of the byte containing bit 0 which is the starting address of the represented data element The following table lists the intrinsic data types used by Intel Fortran the storage required and valid ranges For example the declaration INTEGER 4 is the same as INTEGER KIND 4 and INTEGER 4 Data Type Storage Description BYTE 1 byte A BYTE declaration is a signed integer data type equivalent to INTEGER 1 8 bits INTEGER 1 108 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications INTEGER See INTEGER 2 INTEGER 4 and INTEGER 8 INTEGER 1 1 byte Signed integer value from 128 to 127 8 bits INTEGER 2 2 bytes Signed integer value from 32 768 to 32 767 16 bits INTEGER 4 4 bytes
238. n 226 run time Options 0 eee 86 S S compiler option 82 ESOPO ee ee 7 safe_cray_ptr compiler option 47 save compiler option 47 scalar_rep compiler option 71 scratch files EN 143 searching for include files ann 20 for module mod files 20 segmented record type 144 146 segmented recordS nnnnenn 170 sequential access 288 for recordS E 158 sequential file organization 142 setenv Commande 13 setting breakpoints cceeeceeeeeeeeeeeeeees 91 shared compiler option 62 shared libraries Creating excite aie eel 30 d le Le SE 30 Welle E 30 shared fie checking 0000snn 160 shared libcxa compiler option 62 shell script PUTIN osc cette ca tenes tee ie etek 14 sigaction routine calling RE 224 signal debugging a program 108 description of 224 signal handlnig x ciccesen tierce 224 signal routine UL EE 224 size of executable programs 238 size _lp64 compiler option 64 SOCKS enen e eet an 147 SOX Compiler option 37 special file open routine OPEN statement specifier for 152 specifications IEN 10 specifying data ld E 127 file name 149 SQUARES example program 95 stand compiler option 42 stand90 compiler option 42 stand95 compiler option 42 statement hu Ge 190 static compiler option 62 Static libcxa compiler op
239. nd the last holds a value of 130 Fortran uses these bytes for error checking and end of file references The following program creates the unformatted sequential file shown in the following figure Note The file is sequential by default 1 is FF FF FF FF hexadecimal CHARACTER xyz 3 INTEGER 4 idata 35 DATA idata 35 1 xyz x y z Open the file and write out a 140 byte record 128 bytes block 12 bytes 140 for IDATA then 3 bytes for XYZ OPEN 3 FILE UFSEQ FORM UNFORMATTED WRITE 3 idata WRITE 3 xyz CLOSE 3 END Unformatted Sequential File 126 SE data 12 bytes eier bytes data BOF WE Eege KR ee E ee EOF 1 3 130 H 132 133 144 145 146 147 149 150 151 Dec Hex Dec Dec Hex ec Dec ASCII Dec Dec ko IO EES EISE lass sala ae 3 Xyz 3 ale L Logical record 1 L Logical record 2 BOF Beginning of file byte 75 decimal L Physical block length byte 0 lt L lt 129 EOF End of file byte 130 decimal Unformatted Direct Files An unformatted direct file is a series of unformatted records You can write or read the records in any order you choose All records have the same length 176 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications given by the RECL specifier in an OPEN statement No delimiting bytes separate records or otherwise indicate record structure Yo
240. ndition during execution of a WRITE statement 39severe 39 Error during read FOR IOS_ERRDURREA The Intel Fortran RTL I O system detected an error condition during execution of a READ statement 4Q severe 40 Recursive I O operation FOR IOS_RECIO_OPE While processing an I O statement for a logical unit another I O operation on the same logical unit was attempted such as a function subprogram that performs I O to the same logical unit that was referenced in an expression in an I O list or variable format expression 41 severe 41 Insufficient virtual memory FOR IOS_INSVIRMEM The Intel Fortran RTL attempted to exceed its available virtual memory while dynamically allocating space To overcome this problem increase the per process data limit by using the 1imit C shell or ulimit Bourne and Korn and bash shell commands before you run this program again To determine whether the maximum per process data size is already allocated check the value of the maxdsiz parameter in the sysconfigtab or system configuration file If necessary increase its value Changes to do not 247 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications 248 take effect until the system has been rebooted you do not need to rebuild the kernel if you modify sysconfigtab Before you try to run this program again wait until the new system resources take effect 42 severe 42 No such device FOR
241. nerator See Also Compatibility Options Language Options Descriptions of Data Options no Jalign Default align Analyzes and reorders memory layout for variables and arrays See also align recnbyte align none Default Off Tells the compiler not to add padding bytes anywhere in common blocks or structures 45 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications align no Jcommons or align no Jdcommons Default align nocommons Or align nodcommons Aligns the data items of all common blocks on natural boundaries up to 4 bytes align commons or 8 bytes align dcommons instead of the default byte boundary by adding padding bytes If your command line includes the st and option then the compiler ignores align dcommons align recnbyte Default align rec8byte Zp8 align rec8byte is the same as specifying align records Alternate syntax Z2p 1 2 4 8 16 Specifies alignment constraint for structures on 1 2 4 8 or 16 byte boundaries Aligns fields of records and components of derived types on the smaller of the size boundary specified n can be 1 2 4 8 or 16 or the boundary that will naturally align them Specifying align recnbyte does not affect whether common blocks are naturally aligned or packed This option Is the same as this option Zp align records or align rec8byte Zp1 alignment norecords or ali
242. ng the same value as the last time the routine was invoked your program may not function properly Variables that need to retain their values across subroutine calls should appear in a SAVE statement auto makes all local variables AUTOMATIC causing all variables to be allocated on the stack rather than in local static storage It does not affect variables that have the SAVE attribute or appear in an EQUIVALENCE statement or in a common block save saves all variables in static allocation except local variables within a recursive routine auto might provide a performance gain for your program but if your program depends on variables having the same value as the last time the routine was invoked your program might not function properly double_size 64 128 Default double_size 64 Defines DOUBLE PRECISION and DOUBLE COMPLEX declarations constants functions and intrinsics double_size 64 defines DOUBLE PRECISION declarations constants functions and intrinsics as REAL 8 and defines DOUBLE COMPLEX declarations functions and intrinsics as COMPLEX 16 double_size 128 defines DOUBLE PRECISION declarations constants functions and intrinsics as REAL 16 and for Fortran 90 and 95 defines DOUBLE COMPLEX declarations functions and intrinsics as COMPLEX 32 dyncom blik1 blk2 Enables dynamic allocation of the specified common blocks at run time Example For common blocks A B and C use this syntax dync
243. ning the call stack or displaying registers 87 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications The idb debugger has two modes e dbx default mode e gdb optional mode All examples in this guide are shown in dbx mode S Note For complete information about idb see the idb man page or the online Intel Debugger IDB Manual Debugging Options To use the debugger you should specify the ifort command and the g command line option Traceback information and symbol table information are both necessary for debugging If you specify g the compiler provides the symbol table and traceback information needed for symbolic debugging The notraceback option cancels the traceback information Likely uses of these options at the various stages of program development are as follows During early stages of program development use the g option to create unoptimized code optimization level 00 This option also might be chosen later to debug reported problems from later stages Traceback and symbol table information result in a larger object file During the later stages of program development use g0 or g1 to minimize the object file size and as a result the memory needed for program execution usually with optimized code The g0 option eliminates the traceback information When you have finished debugging your program you can recompile and relink to create an optimized exec
244. nnnnnnnnnnnnnnne 29 Shared Library Restrictions EE 29 Installing Shared Ree 30 Allocating Common Blocks E 30 Guidelines for Using the dyncom Option 31 Why Use a Dynamic Common Block 31 Allocating Memory to Dynamic Common Block 32 Compile E 32 Compiler Options Overview ee EREESESESESEEEEEREENESE es 32 Compiler Options Detalls eene 33 Styles of Compiler EES 33 Using Multiple ifort EEN EEEEEAAESE 33 Table Of Contents Using the OPTIONS Statement to Override Ootons 34 Getting Help on ee 34 Compiler Directives Related to Options ccccccccccceeeeeeeeeeeeeeeeeeeeeeeeenenneeeeeeees 34 Code Generation EES EESEEEESEE 35 Descriptions of Code Generation Options cccccceeeceeeeeeeeeeeeeeeenneeeeeeeeeeeeee 35 See 35 noJreentrancy keyword AEN 35 sox IA 32 systems EE 36 EENEG 36 Descriptions of Compatibility Oto 36 Slee a eee ab ec ni ae noe iam ee es 36 SAGSUINO NO DSCC ee dhe ebe erected EE Eege 37 SEENEN 37 cy ace La Ag RNa te ee meee mee eee ee eee eee ee 37 foscomp all and ee ee 38 foscomp NO NESHOMCINIG Ee cob Leet EE 38 foscomp ee EE 38 I SCOIND nee een E 38 PHO SCONIND NOI DS E 38 OSCOMDd NONOGICAIS EENEG 39 Sales 39 wl dE 39 Compilation Diagnostics Options cise 8 siete esau el cunist nic eeie el ie piatees ele etblene 40 Table Of Contents Descriptions of Compilation Diagnostics COpotons e 41 ST 41 no error_limMmit eae eee ee ee ene eee ee ene ene a ene eee see ee eee 41 openmp_
245. nonnative floating point formats and in big endian INTEGER or floating point format Supported nonnative floating point formats include VAX little endian floating point formats supported by VAX FORTRAN standard IEEE big endian floating point format found on most Sun Microsystems systems and IBM RISC System 6000 systems IBM floating point formats associated with the IBM s System 370 and similar systems and CRAY floating point formats Converting unformatted data instead of formatted data is generally faster and is less likely to lose precision of floating point numbers The native memory format includes little endian integers and little endian IEEE floating point formats S_ floating for REAL KIND 4 and COMPLEX KIND 4 declarations T_floating for REAL KIND 8 and COMPLEX KIND 8 declarations and IEEE X_floating for REAL KIND 16 and COMPLEX KIND 16 declarations The keywords for supported nonnative unformatted file formats and their data types are listed in the following table Nonnative Numeric Format Keywords and Supported Data Types Keyword Description BIG_ENDIAN Big endian integer data of the appropriate INTEGER size one two four or eight bytes and big endian IEEE floating point formats for REAL and COMPLEX single and double and extended precision numbers INTEGER KIND 1 or INTEGER 1 data is the same for little endian and big endian CRAY Big endian integer data of the appropriate INTEGER size
246. nt assigned to a double precision variable be evaluated in double precision instead of single precision The Fortran standard requires that the constant be evaluated in single precision Certain programs created for FORTRAN 77 compilers may show different floating point results because they rely on single precision constants assigned to a double precision variable to be evaluated in double precision In the following example if you specify fpconstant identical values are assigned to D1 and D2 If you omit fpconstant the compiler will obey the standard and assign a less precise value to D1 REAL KIND 8 D1 D2 DATA D1 2 71828182846182 REAL KIND 4 value expanded to double DATA D2 2 71828182846182D0 Double value assigned to double fpen Default fpe3 Specifies floating point exception handling at run time for the main program This includes whether exceptional floating point values are allowed and how precisely run time exceptions are reported This option controls how the following exceptions are handled e When floating point calculations result in a divide by zero overflow or invalid operation e When floating point calculations result in an underflow e When adenormalized number or other exceptional number positive infinity negative infinity or a NaN is present in an arithmetic expression You can choose the following e fpe0 specifies underflow gives 0
247. ntation COMPLEX KIND 16 Representation safe_cray_ptr Default Off assume that Cray pointers do alias other variables Requires that the compiler assume that Cray pointers do not alias that is do not specify sharing memory between other variables Consider the following example pointer pb b pb getstorage do i 1 n b i a i 1 enddo By default the compiler assumes that b and a are aliased To prevent such an assumption specify the safe_cray_ptr option and the compiler will treat b i anda i as independent of each other 51 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications However if the variables are intended to be aliased with Cray pointers using the safe_cray_ptr option produces incorrect results For the code example below safe_cray_ptr should not be used pointer pb b pb loc a 2 do i l n b i a i 1 enddo zero Default Off zero Initializes to zero all local scalar variables of intrinsic tyoe INTEGER REAL COMPLEX or LOGICAL that are saved and not already initialized For this option to be effective you must use save on the command line or have variables in your code specifically marked as SAVE External Procedures Options The external procedures options let you specify how external procedures are called Descriptions of External Procedures Options assume no underscore Default assume nounderscore Altern
248. o evaluate the expressions involving floating point operands in the precision indicated by the variable types declared in the program By default intermediate floating point expressions are maintained in higher precision 56 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications See also Floating Point Arithmetic Options for Itanium Based Systems in Volume II Optimizing Applications IPF_fltacc Itanium based systems only Default Off Disables optimizations that affect floating point accuracy If the default setting is used IPF_fltacc the compiler might apply optimizations that reduce floating point accuracy You can use IPF_fltacc or fltconsistency to improve floating point accuracy but at the cost of disabling some optimizations See also Floating Point Arithmetic Options for Itanium Based Systems in Volume II Optimizing Applications IPF_fmal Itanium based systems only Default Off Enables the combining of floating point multiply and add subtract operations into a single operation IPF_fp_speculationmode Itanium based systems only Default IPF_fp_speculationfast Enables floating point operations in one of the following modes fast Speculate on floating point operations safe Speculate on floating point operations only when it is safe strict Disables speculation on floating point operations off Same as strict See also Floating Point
249. o logical units by using one of the following methods e Using default values such as a preconnected unit e Supplying a file name and possibly a directory in an OPEN statement e Using environment variables Using Default Values In the following example the PRINT statement is associated with a preconnected unit stdout by default 146 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications PRINT 100 The READ statement associates the logical unit 7 with the file fort 7 because the FILE specifier was omitted by default OPEN UNIT 7 STATUS NEW READ 7 100 Supplying a File Name in an OPEN Statement For example OPEN UNIT 7 FILE FILNAM DAT STATUS OLD The FILE specifier in an OPEN statement typically specifies only a file name such as testdata or contains both a directory and file name such as usr proj testdata The DEFAULTFILE specifier in an OPEN statement typically specifies a pathname that contains only a directory such as usr proj or both a directory and file name such as usr proj testdata Implied OPEN Performing an implied OPEN means that the FILE and DEFAULTFILE specifier values are not specified and an environment variable is used if present Thus if you used an implied OPEN or if the FILE specifier in an OPEN statement did not specify a file name you can use an environment variable to specify a file name or a pathna
250. ode resides in a cpp file C semantics are applied to external names often resulting in linker errors In this case use the extern C syntax see C C Naming Conventions C code accessing module data in cpp file extern C float examp_mp_a 3 extern C int examp_mp_il examp_mp_i2 extern C char examp_mp_line 80 extern C struct int n char info 30 examp_mp_mydata You can also define a module procedure in C and make that routine part of a Fortran module by using the ALIAS directive The C code is C procedure void pythagoras float a float b float c c float sqrt a a b b 213 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Using the same example when the C code resides in a cpp file use the extern C syntax see C C Naming Conventions C procedure extern C void pythagoras float a float b float c c float sqrt a a b b The Fortran code to define the module CPROC Fortran 95 90 Module including procedure MODULE CPROC INTERFACE SUBROUTINE PYTHAGORAS a b res DECS ATTRIBUTES C PYTHAGORAS DECS ATTRIBUTES REFERENCE res res is passed by REFERENCE because its individual attribute overrides the subroutine s C attribute REAL a b res a and b have the VALUE attribute by default because the subroutine has the C attribute END SUBROUTINE END INTERFACE END MODULE
251. ollows ifort exl f uopen_ c Source Code for the C Function and Header File The following example shows the C language function called uopen_ and its associated header file 165 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications File uopen h header file for uopen_ c S ifndef UOPEN define UOPEN 1 KEN NS Function Prototypes KEN SS int uopen_ char file name access read name of the file to open int open_flags access read READ WRITE see file h or open 2 int create_mode access read set if new file to be created int lun access read logical unit file opened on int file length access read number of characters in file name endif End of file uopen h xx File uopen_ c K xx This routine opens a file using data passed by Intel Fortran RTL kk SE INCLUDE FILES ay finclude lt sys types h gt finclude lt sys stat h gt include lt sys file h gt include uopen h Include file for this module int uopen_ file_name open_flags create_mode lun file_length 166 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications xx Open a file using the parameters passed by the calling Intel KK Fortran program kk xx Formal Parameters SS char file name access read
252. om a b c 49 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications integer_size 16 32 64 Default integer_size 32 Alternate syntax i1 2 4 8 where 2 4 and 8 stand for the KIND of integer and logical variables Specifies the default size in bits of integer and logical declarations constants functions and intrinsics where n is 16 32 or 64 e nis 16 Makes the default integer and logical variables 2 bytes long INTEGER and LOGICAL declarations are treated as KIND 2 Alternate syntax i2 See also INTEGER KIND 2 Representation e nis 32 Makes the default integer and logical variables 4 bytes long INTEGER and LOGICAL declarations are treated as KIND 4 Alternate syntax i4 See also INTEGER KIND 4 Representation e nis 64 Makes the default integer and logical variables 8 bytes long INTEGER and LOGICAL declarations are treated as KIND 8 Alternate syntax i8 See also INTEGER KIND 8 Representation P9 Default Off Compiles and links for function profiling with gprof 1 This is the same as specifying p or qp real_size 32 64 128 Default real_size 32 Alternate syntax r 8 16 where 8 and 16 stand for the KIND of real variables Specifies the default size in bits of real and complex declarations constants functions and intrinsics where n is 32 64 or 128 e nis 32 Defines REAL declarations constants functions and intrinsics as REAL KIND 4
253. om Both Assemble as for IA 32 applications ias for Itanium optional ee based applications Link ld 1 Both By default the compiler generates an object file directly without calling the assembler However if you need to use specific assembly input files and then link them with the rest of your project you can use an assembler for these files The compiler passes object files and any unrecognized filename to the linker The linker then determines whether the file is an object file o or a library a or shared library so The compiler handles all types of input files correctly Thus you can use it to invoke any phase of compilation Preprocess Phase Preprocessing performs such tasks as preprocessor symbol macro substitution conditional compilation and file inclusion The compiler preprocesses files as an optional first phase of the compilation Source files that have a filename extension of Cep P F90 FOR EIN or FPP are automatically preprocessed by the compiler For example the following command preprocesses a source file that contains standard Fortran preprocessor directives then passes the preprocessed file to the compiler and linker ifort source fpp If you want to preprocess files that have another extension you have to overtly specify the preprocessor You do not usually need to specify preprocessing for Fortran source programs The preprocessor is necessary only if your program uses C style preproce
254. om wherever the call site is and terminate execution You can specify arguments that generate a stack trace with the user supplied string as the header and instead of terminating execution return control to the caller to continue execution of the application For example CALL TRACEBACKQQ STRING Done with pass 1 USER_EXIT_CODE 1 By specifying a user exit code of 1 control returns to the calling program Specifying a user exit code with a positive value requests that specified value be returned to the operating system The default value is 0 which causes the application to abort execution Using Libraries Using Libraries Overview See these topics Libraries Provided by Intel Fortran Portability Library Overview Math Libraries Overview Libraries Provided by Intel Fortran Intel Fortran provides different types of libraries such as static or DLL single threaded or multi threaded for certain libraries The table below shows the libraries provided by the compiler File Description crtxi o CEEX O for_main o icrt internal map iert link ifcore_msg cat libcprts a C standard language library 226 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications libcprts so libcprts so 5 libcxa a C language library indicating I O data location libcxa so libcxa so 5 libcxaguard a libcxaguard so libcxaguard so 5 libguide a OpenMP static library for
255. ompiled and linked by this command ifort filel 90 file2 90 Working with Multi Directory Module Files For an example of managing modules when the mod files could be produced in different directories assume that the program mod dert 90 resides in directory usr yourdir test t and this program contains a module defined as follows file mod_def f90 module definedmod end module The compiler command 17 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications ifort c mod _def f90 produces two files mod_def o and definedmod mod in directory usr yourdir test t If you need to use the above mod file in another directory for example in directory usr yourdir test t2 where the program usemod uses the definedmod mod file do the following file use_mod_def f90 program usemod use definedmod end program To compile the above program use this command ifort c use_mod_def f 90 I usr yourdir test t where the Idir option provides the compiler with the path to search and locate the definedmod mod file Parallel Invocation with a makefile The programs in which modules are defined support the compilation mechanism of parallel invocation with a makefile for interorocedural optimizations of multiple files and of the whole program Consider the following code testl1 90 module ml end module test2 90 subroutine s2 use ml end subroutine test3 90 subroutine
256. on to optimize the code for the Intel Pentium 4 and Intel Xeon processor e For Itanium based applications uses the tpp2 option to optimize the code for the Intel Itanium 2 processor F Note On operating systems that support characters in Unicode multi byte format the compiler will process file names containing Unicode characters Input Files and Filename Extensions The Intel Fortran Compiler interprets the type of each input file by its filename extension such as a f for o and soon Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Filename Interpretation Action filename a Object library Passed to 1d filename Ee Fortran fixed Compiled by the Intel Fortran filename ftn form source compiler filename for filename i filename fpp Fortran fixed Preprocessed by the Intel Fortran filename F form source preprocessor fpp then compiled by the filename F90 Intel Fortran compiler filename FOR filename FIN filename FPP filename f90 Fortran free form Compiled by the Intel Fortran compiler filename i90 source filename s Assembly file Passed to the assembler IA 32 compiler or the Intel Itanium assembler Itanium based compiler filename o Compiled object Passed to 1d file You can use the compiler configuration file to specify default directories for input libraries To specify additional directorie
257. ons __ 1386 i386 _ ia64 Itanium __ia64 ia64 _OPENMP n n 200011 Both This preprocessor symbol has the form YYYYMM where YYYY is the year and MM is the month of the OpenMP Fortran specification supported This preprocessor symbol can be used in both fpp and the Fortran compiler conditional compilation It is available only openmp is specified _PRO_INSTRUMENT Off Both Defined when prof_gen is specified Defining Preprocessor Symbols You can use the D option to define the symbol names to be used during preprocessing This option performs the same function as the define preprocessor directive The format of this option is Dname value where e name is the name of the symbol to define e value specifies an optional value to substitute for name If you do not enter a value name is set to 1 The value should be enclosed in quotation marks if it contains spaces or special characters Preprocessing replaces every occurrence of name with the specified value For example to define a symbol called SITZE with the value 100 use the following command ifort fpp DSIZE 100 progl f 24 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Preprocessing replaces all occurrences of SIZE with the specified value 100 before passing the preprocessed source code to the compiler Assume that the program contains this declaration REAL VECTOR SIZE In th
258. or 32 bit applications Linux supplies its own assembler as For Itanium based applications use the Itanium assembler ias For example to link some specific input file to the Fortran project object file do the following 1 Issue acommand using the S option to generate an assembly code file file si ifort S c file f 2 To assemble the file s file call the Itanium assembler with this command ias Nso p32 o file o file s Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications where the following assembler options are used Nso suppresses the sign on message p32 enables defining 32 bit elements as relocatable data elements This option is available for backward compatibility o file o indicates the output object filename Linker The compiler calls the system linker 1d 1 to produce an executable file from the object files Default Behavior of the Intel Fortran Compiler The compiler generates one or more executable files of one or more input files By default it performs the following actions e Searches for all files including library files in the current directory e Passes options designated for linking to the linker e Passes user defined libraries to the linker e Displays error and warning messages e Performs default settings and optimizations unless these options are overridden by specific options settings e For lA 32 applications uses the tpp7 opti
259. or mixed language applications the Intel Fortran main program can call subprograms written in Intel C if the appropriate calling conventions are used see Calling C Procedures from a Fortran program Intel Fortran subprograms can be called by Intel C main programs Calls to the Subprogram You can use subprograms in static libraries if the main program is written in Intel Fortran or Intel C You can use subprograms in shared libraries in mixed language applications if the main program is written in Intel Fortran or Intel C Summary of Mixed Language Issues Mixed language programming involves a call from a routine written in one language to a function procedure or subroutine written in another language For example a Fortran main program may need to execute a specific task that you want to program separately in an assembly language procedure or you may need to call an existing shared library or system procedure Mixed language programming is possible with Intel Fortran and Intel C because each language implements functions subroutines and procedures in approximately the same way The following table shows how different kinds of routines from each language correspond to each other For example a C main program could call an external void function which is actually implemented as a Fortran subroutine Language Equivalents for Calls to Routines Language Call with Return Value Call with No Return Value Fortran FU
260. organization of a file is specified by means of the ORGANIZATION specifier in the OPEN statement You can store sequential files on magnetic tape or disk devices and can use other peripheral devices such as terminals pipes and line printers as sequential files You must store relative files on a disk device Sequential Organization A sequentially organized file consists of records arranged in the sequence in which they are written to the file the first record written is the first record in the file the second record written is the second record in the file and so on As a result records can be added only at the end of the file Sequential files are usually read sequentially starting with the first record in the file Sequential files with a fixed length record type that are stored on disk can also be accessed by relative record number direct access Relative Organization Within a relative file are numbered positions called cells These cells are of fixed equal length and are consecutively numbered from 1 to n where 1 is the first cell and nis the last available cell in the file Each cell either contains a single record or is empty Records in a relative file are accessed according to cell number A cell number is a record s relative record number its location relative to the beginning of the file By specifying relative record numbers you can directly retrieve add or delete records regardless of their locations dir
261. ortran Compiler for Linux Systems User s Guide Volume l Building Applications To prevent the compiler from searching the default path specified by the FPATH environment variable use the X option You can specify these options in the configuration file i fort cfg or on the command line For example to direct the compiler to search the path alt include instead of the default path use the following command line X I alt include newmain f Configuration files and response files are slightly different variations in the same idea the concept that you can use files with various options to eliminate the need to enter the same commands again and again Response files are also known as indirect command files Configuration Files You can use a configuration cfg file to e Decrease the time you spend entering command line options e Ensure consistency of often used commands You can insert any valid command line options into a configuration file The compiler processes options in the configuration file in the order in which they appear followed by the command line options that you specify when you invoke the compiler 8 Note Options placed in the configuration file will be included each time you run the compiler If you have varying option requirements for different projects use response files By default a configuration file named ifort cfg is used This file resides in the same directory where the compiler execu
262. ortran strings C must account for the length argument passed along with the string address For example Fortran code INTERFACE SUBROUTINE Pass_Str string CHARACTER string END INTERFACE The C routine must expect two arguments void pass_str char string unsigned int length_arg This interface handles the hidden length argument but you must still reconcile C strings that are null terminated and Fortran strings that are not In addition if the data assigned to the Fortran string is less than the declared length the Fortran string will be blank padded Rather than trying to handle these string differences in your C routines the best approach in Fortran C mixed programming is to adopt C string behavior whenever possible Fortran functions that return a character string using the syntax CHARACTER place a hidden string argument and the length of the string at the beginning of the argument list C functions that implement such a Fortran function call must declare this hidden string argument explicitly and use it to return a value The C return type should be void However you are more likely to avoid errors by not using character 209 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications string return functions Use subroutines or place the strings into modules or global variables whenever possible Returning Character Data Types
263. our application Descriptions of Libraries Options no_cpprt Default cxxlib icc use Intel C libraries Specifies that C run time libraries should not be linked This option exists for GNU compatibility reasons to disable the use of the cpp run time libraries during link There is no cpprt or yes_cpprt option 60 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications nodefaultlibs Default Off include default libraries Specifies that standard libraries should be used when linking This option exists for GNU compatibility reasons There is no defaultlibs option See also nostdlib i_dynamic Default Off Instructs the linker to link Intel provided libraries dynamically Ldir Default Off Instructs the linker to search dir for libraries no threads Default nothreads Specifies whether or not multithreaded libraries should be linked against If you specify threads this sets the reentrancy threaded option nostdlib Default Off Specifies that standard libraries and startup files should be used when linking This option exists for GNU compatibility reasons There is no stdlib option shared Default Off Specifies that the compiler should build a dynamic shared object DSO instead of an executable 61 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications See also Creating Shared Libraries shared libcxa Links t
264. output specifies the file name The following command requests a file name of prog1 out for the source file test1 f ifort o progl out testl f Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications If you specify the c option with the o output option you rename the object file not the executable program file If you specify lt and omit the o output option the compiler names the object files with a o suffix substituted for the source file suffix s Note You cannot use c and o together with multiple source files The default optimization level is 02 unless you specify lt Temporary Files Created by the Compiler or Linker Temporary files created by the compiler or linker reside in the directory used by the operating system to store temporary files To store temporary files the driver first checks for the TMP environment variable If defined the directory that TMP points to is used to store temporary files If the TMP environment variable is not defined the driver then checks for the TMPDIR environment variable If defined the directory that TMPDIR points to is used to store temporary files If the TMPDIR environment variable is not defined the driver then checks for the TEMP environment variable If defined the directory that TEMP points to is used to store temporary files If the TEMP environment variable is not defined the tmp directory is used
265. pened using the READONLY keyword cannot be deleted when it is closed e Inthe CLOSE statement specify the keyword STATUS DELETE If you opened an external file and did an inquire by unit but do not like the default value for the ACCESS specifier you can close the file and then reopen it explicitly specifying the ACCESS desired There usually is no need to close preconnected units Internal files are neither opened nor closed Record Operations Record Operations Overview See these topics Record I O Statement Specifiers Record Access File Sharing Specifying the Initial Record Position Advancing and Nonadvancing Record I O Record Transfer Record I O Statement Specifiers After you open a file or use a preconnected file you can use the following statements 156 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications e READ WRITE ACCEPT and PRINT to perform record I O e BACKSPACE ENDFILE and REWIND to set record position within the file e DELETE REWRITE TYPE and FIND to perform various operations The record I O statement must use the appropriate record I O form formatted list directed namelist or unformatted You can use the following specifiers with the READ and WRITE record I O statements e UNIT specifies the unit number to or from which input or output will occur e END specifies a label to branch to if end of file occurs only applies to input sta
266. plications Examples of Applying Default Pathnames and File Names For example for an implied OPEN of unit number 3 Intel Fortran would check the environment variable FORTS If the environment variable FORT3 was set its value is used If itis not set the system supplies the file name fort 3 In the following table assume the current directory is usr smith and the I O uses unit 1 as in the statement READ 1 100 OPEN FILE value OPEN DEFAULTFILE value FORT environment variable value Resulting pathname not specified not specified not specified usr smith fort 1 not specified not specified test dat usr smith test dat not specified not checked usr tmp t dat usr tmp t dat not specified tmp not specified tmp fort 1 not specified tmp testdata tmp testdata not specified usr lib testdata usr lib testdata file dat usr group not checked usr group file dat tmp file dat not checked not checked tmp file dat file dat not specified not specified usr smith file dat When the resulting file pathname begins with a tilde character C shell style pathname substitution is used regardless of what shell is being used such as a top level directory below the root For additional information on tilde pathname substitution see csh 1 Rules for Applying Default Pathnames and File Names Inte
267. plies to records in relative or sequential files The file related statements OPEN INQUIRE and CLOSE apply to any relative or sequential file Forms of I O Statements Each type of record UO statement can be coded in a variety of forms The form you select depends on the nature of your data and how you want it treated When opening a file specify the form using the FORM specifier The following are the forms of I O statements e Formatted I O statements contain explicit format specifiers that are used to control the translation of data from internal binary form within a program to external readable character form in the records or vice versa e List directed and namelist I O statements are similar to formatted statements in function However they use different mechanisms to control the translation of data formatted I O statements use explicit format specifiers and list directed and namelist I O statements use data types 138 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications e Unformatted I O statements do not contain format specifiers and therefore do not translate the data being transferred important when writing data that will be read later Formatted list directed and namelist I O forms require translation of data from internal binary form within a program to external readable character form in the records Consider using unformatted I O for the following reasons
268. pplications The following ifort command compiles but does not link the free format source file typedefs_1 90 which contains a MODULE TYPEDEFS_1 The command creates files typedefs_1 mod and typedefs_1 o The object file is retained automatically Specifying the c option prevents linking ifort c typedefs_1 f90 Compiling Fortran 95 90 and C Source Files The following ifort command compiles the free format Fortran main program myprog 90 which references the module TYPEDEFS_1 with a USE TYPEDEFS_1 statement it uses the object file created in the previous example The module file typedefs_1 mod is read from the current directory The main program calls a function written in C The C routine named utilityx_ is declared in a file named utilityx c ifort myprog f90 typedefs_1 o utilityx c ifort does not recognize a source file with a c extension as needing to be compiled by the C compiler Instead it passes it as an unknown to the linker You will need to call the C compiler to compile ut ilityx c Renaming the Output File The following ifort command compiles the free format Fortran source files circle calc f90 and sub 90 together ifort c circle calc f90 sub f90 The default optimization level 02 applies to both source files during compilation Because the c option is specified the object files are not passed to the linker In this case the named output files are the object files Like the previous command th
269. profile data with 32 bit counters The default is to produce profile data with 64 bit counters to handle large numbers of events This option allows compatibility with earlier compilers vms Default Off Causes the run time system to behave like HP Fortran on OpenVMS Alpha systems and VAX systems VAX FORTRAN in the following ways e Certain defaults In the absence of other options vms sets the defaults as check format and check output_conversion e Alignment The vms option does not affect the alignment of fields in records or items in common blocks Use align norecords to pack fields of records on the next byte boundary for compatibility with HP Fortran on OpenVMS systems e Carriage control default lf vms ccdefault default is specified carriage control defaults to FORTRAN if the file is formatted and the unit is connected to a terminal e INCLUDE qualifiers LIST and NOLIST are recognized at the end of the file name in an INCLUDE statement at compile time If the file name in the INCLUDE statement does not specify the complete path the path used is the current directory Note that if vms is not specified the path used is the directory where the file that contains the INCLUDE statement resides 39 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications e Quotation mark character A quotation mark character is recognized as starting an octal constant 0 7 instead of a characte
270. program with a prefix of mains followed by the file name S n more progout f90 Executes the shell command more to display file progout 90 then returns to the debugger environment S how thread Lists all threads known to the debugger status Displays breakpoints and tracepoints with their event numbers See also delete SSP Steps one source statement including stepping into calls of a subprogram For Intel Fortran I O statements intrinsic procedures library routines or other subprograms use the next Command instead of step to step over the subprogram call Compare with next see also return stop in foo Stops execution breakpoint at the beginning of routine foo stop at 100 Stops execution at line 100 breakpoint of the current source file stopi at Stops execution at address xxxxxxx of the current XXXXXXX executable program thread n Identifies or sets the current thread context 92 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications aa Displays a message when the debuggee or user program GEN accesses the specified memory location For example watch 0x140000170 watch variable m Displays a message when the debuggee or user program accesses the variable specified by m whatis symbol Displays the data type of the specified symbol when at 9 command Executes a command or commands When
271. ptor Error Descriptor C Value Value Reference String 1 1 String 1 1 Reference No Len Reference Error Reference Value size dependent Value size dependent Reference Descriptor Error Descriptor C REFERENCE Reference Value Reference Reference either Len End or Len Mixed String 1 1 Reference No Len Reference Error Reference Reference Value size dependent Reference Descriptor Error Descriptor The procedure name is all lowercase for all the calling conventions The terms in the above table mean the following 183 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications value reference Value Reference Len End or Len Mixed No Len or Len Mixed No Len String 1 1 Error Descriptor Size dependent 184 Argument assigned the VALUE attribute Argument assigned the REFERENCE attribute The argument value is pushed on the stack All values are padded to the next 4 byte boundary On IA 32 systems the 4 byte argument address is pushed on the stack On Itanium based systems the 8 byte argument address is pushed on the stack For certain string arguments e Len End applies when nomixed_str_len_arg is set The length of the string is pushed by value on the stack after all of the other arguments This is the default e Len Mixed applies when mixed_str_len_arg is set The length of the
272. ptors Handling Character Strings Handling User Defined Types Handling Numeric Complex and Logical Data Types Normally passing numeric data does not present a problem If a C program passes an unsigned data type to a Fortran routine the routine can accept the argument as the equivalent signed data type but you should be careful that the range of the signed type is not exceeded 198 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications The table of Equivalent Data Types summarizes equivalent numeric data types for Fortran and C C C and C do not directly implement the Fortran types COMPLEX 4 COMPLEX 8 and COMPLEX 16 However you can write structures that are equivalent The type COMPLEX 4 has two fields both of which are 4 byte floating point numbers the first contains the real number component and the second contains the imaginary number component The type COMPLEX is equivalent to the tyoe COMPLEX 4 The types COMPLEX 8 and COMPLEX 16 are similar except that each field contains an 8 byte or 16 byte floating point number respectively Note On IA 32 systems Fortran functions of type COMPLEX place a hidden COMPLEX argument at the beginning of the argument list C functions that implement such a call from Fortran must declare this hidden argument explicitly and use it to return a value The C return type should be void Following are the C C structure definitions for
273. r information 228 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Group user and process ID are INTEGER 4 variables Login name and host name are character variables The functions GETGID and GETUID are provided for portability but always return 1 Process Control Routines Process control routines control the operation of a process or subprocess You can wait for a subprocess to complete with either SLEEP or ALARM monitor its progress and send signals via KILL and stop its execution with ABORT In spite of its name KILL does not necessarily stop execution of a program Rather the routine signaled could include a handler routine that examines the signal and takes appropriate action depending on the code passed Note that when you use SYSTEM commands are run in a separate shell Defaults set with the SYSTEM function such as current working directory or environment variables do not affect the environment the calling program runs in The portability library does not include the FORK routine On Linux systems FORK creates a duplicate image of the parent process Child and parent processes each have their own copies of resources and become independent from one another Numeric Values and Conversion Routines Numeric values and conversion routines are available for calculating Bessel functions data type conversion and generating random numbers Some of these functions have equiva
274. r INQUIRE statement For example OPEN UNIT 10 FILE FILNAM STATUS OLD ERR 999 221 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications If an error is detected during execution of this OPEN statement control transfers to the statement at label 999 Using the lOSTAT Specifier You can use the lIOSTAT specifier to continue program execution after an I O error and to return information about I O operations Certain errors are not returned in lOSTAT The IOSTAT specifier can supplement or replace the END EOR and ERR branch transfers Execution of an I O statement containing the IOSTAT specifier suppresses the display of an error message and defines the specified integer variable array element or scalar field reference as one of the following e A value of 2 if an end of record condition occurs with nonadvancing reads e A value of 1 if an end of file condition occurs e A value of 0 for normal completion not an error condition end of file or end of record condition e A positive integer value if an error condition occurs This value is one of the Fortran specific IOSTAT numbers listed in the run time error message See un Time Error Messages Following the execution of the I O statement and assignment of an IOSTAT value control transfers to the END EOR or ERR statement label if any If there is no control transfer normal execution continues You can includ
275. r literal e Deleted records in relative files When a record in a relative file is deleted the first byte of that record is set to a known character currently Attempts to read that record later result in ATTACCNON errors The rest of the record the whole record if vms s not specified is set to nulls for unformatted files and spaces for formatted files e ENDFILE records When an ENDFILE is performed on a sequential unit an actual 1 byte record containing a Ctrl Z is written to the file If vms is not specified an internal ENDFILE flag is set and the file is truncated The vms option does not affect ENDFILE on relative files these files are truncated e Implied logical unit numbers The vms option enables Intel Fortran to recognize certain environment variables at run time for ACCEPT PRINT and TYPE statements and for READ and WRITE statements that do not specify a unit number such as READ 1000 e Treatment of blanks in input The vms option causes the defaults for the keyword BLANK in OPEN statements to become NULL for an explicit OPEN and ZERO for an implicit OPEN of an external or internal file For more information see the description of the OPEN statement e OPEN statement effects Carriage control defaults to FORTRAN if the file is formatted and the unit is connected to a terminal checked by means of isatty 3 Otherwise carriage control defaults to LIST The vms option affects the record
276. ran Program Compiling and Linking Intel Fortran C Programs Your application can contain both C and Fortran source files If your main program is a Fortran source file myprog for that calls a routine written in C cfunc c you can use the following sequence of commands to build your application icc c cfunc c ifort o myprog myprog for cfunc o The icc for Intel C command compiles cfunc c The c option specifies that the linker is not called This command creates cfunc o The ifort command compiles myprog for and links cfunc o with the object file created from myprog for to create myprog Using Modules in Fortran C Mixed Language Programming Modules are the simplest way to exchange large groups of variables with C because Intel Fortran modules are directly accessible from C C The following example declares a module in Fortran then accesses its data from C Fortran code 212 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications F90 Module definition MODULE EXAMP REAL A 3 INTEGER Il I2 CHARACTER TYPE HARACTER 30 INFO END TYPE MYDATA END MODULE EXAMP C code C code accessing module data extern float examp_mp_a 3 extern int examp_mp_il examp_mp_i2 extern char examp_mp_line 80 extern struct int n char info 30 examp_mp_mydata When the C c
277. re This is the default o When mixed_str_len_arg is set the length of the string is pushed by value on the stack immediately after the address of the beginning of the string Since all strings in C are pointers C expects strings to be passed by reference without a string length In addition C strings are null terminated while Fortran strings are not There are two basic ways to pass strings between Fortran and C convert Fortran strings to C strings or write C routines to accept Fortran strings To convert a Fortran string to C choose a combination of attributes that passes the string by reference without length and null terminate your strings For example INT 208 ERFACE Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications SUBROUTINE Pass_Str string DECS ATTRIBUTES C DECORATE ALIAS Pass_Str Pass_Str CHARACTER string DECS ATTRIBUTES REFERENCE string END SUBROUTINE END INTERFACE CHARACTER 40 forstring DATA forstring This is a null terminated string C The following example shows the extension of using the null terminator for the string in the Fortran DATA statement see C Strings in the Intel Fortran Language Reference DATA forstring This is a null terminated string C The C interface is void Pass_Str char string To get your C routines to accept F
278. rease the number of characters passed in for this argument to be at least 10 characters in length Verify that the DATE and ZONE arguments also meet their minimum lengths 177 severe 177 ZONE argument to DATE_AND_TIME is too short LEN n required LEN 5 FOR IOS_ SHORTZONEARG The number of characters associated with the ZONE argument to the DATE_AND_TIME intrinsic was shorter than the required length You must increase the number of characters passed in for this argument to be at least 5 characters in length Verify that the DATE and TIME arguments also meet their minimum lengths 178 severe 178 Divide by zero FOR IOS_DIV A floating point or integer divide by zero exception occurred 179 severe 179 Cannot allocate array overflow on array size calculation FOR IOS_ARRSIZEOVF An attempt to dynamically allocate storage for an array failed because the required storage size exceeds addressable memory 256 severe 256 Unformatted I O to unit open for formatted transfers FOR IOS_UNFIO_FMT Attempted unformatted I O to a unit where the OPEN statement FORM specifier indicated the file was formatted Check that the correct unit file was specified If the FORM specifier was not present in the OPEN statement and the file contains unformatted data specify FORM UNFORMATTED in the OPEN statement Otherwise if appropriate use formatted I O such as list directed or namelist I O 257
279. reated by Intel Fortran when the fpscomp option such as fpscomp ioformat was specified If you are accessing files from another platform that organizes them differently see Converting Unformatted Data Overview The records in an unformatted sequential file can vary in length Unformatted sequential files are organized in chunks of 130 bytes or less called physical blocks Each physical block consists of the data you send to the file up to 128 bytes plus two 1 byte length bytes inserted by the compiler The length bytes indicate where each record begins and ends A logical record refers to an unformatted record that contains one or more physical blocks See the following figure Logical records can be as big as you want the compiler will use as many physical blocks as necessary When you create a logical record consisting of more than one physical block the compiler sets the length byte to 129 to indicate that the data in the current physical block continues on into the next physical block For example if you write 140 bytes of data the logical record has the structure shown in the following figure 175 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Logical Record in Unformatted Sequential File 126 bytes data SC bytes data Ge Dec Dec GE 129 12 E One logical record The first and last bytes in an unformatted sequential file are reserved the first contains a value of 75 a
280. record operations OVETV OW ccccccceeeeeeeeeeeeeteeees 157 record overhead 146 record position CNL ee KEE 160 specifying mal 160 record size 162 record transier 162 record transfer characteristics OPEN statement specifiers for 152 record type CHOOSING EE 144 record EIERE 144 158 record types len 170 record types eege eer 170 record variable ssssseeeeeesseeeeee 99 recursive compiler option 37 redirecting command line output 27 reentrancy compiler option 37 REFERENCE proper 183 relative file organization 142 relative Dathmame 10 renaming an output file 16 representation routines 230 response files cceeeeeeeeeeeees 21 restrictions in creating shared libraries 30 returning character data types 209 REWIND statement 138 158 REWRITE statement 138 139 158 rules for default file names 149 for default pathnames 149 run time environment variables 234 run time Checkimg 86 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications run time error messages eege 242 run time errors wl el Ghia et Sia Sear Sa Se ee Oe 222 Run Time Library RTL and le EE 108 Run Time Library RTL default error PIOCESSING DE 217 Run Time Library RTL default exception handler s nnnnnne
281. rect Any case can be used in the Fortran source code including mixed case since the name is changed to all lowercase 187 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications e Mixed case names If the name of a routine appears as mixed case in C and you cannot change the name then you can resolve this naming conflict by using the Fortran ATTRIBUTES ALIAS option ALIAS is required in this situation because otherwise Fortran will not preserve the mixed case name To use the ALIAS option place the name in quotation marks exactly as it is to appear in the o file The following is an example for referring to the C function My_Proc DECS ATTRIBUTES ALIAS My_Proc_ My_Proc Fortran Module Names and ATTRIBUTES Fortran module entities data and procedures have external names that differ from other external entities Module names use the convention MODULENAME_mp_ENTITY_ MODULENAME is the name of the module and ENTITY is the name of the module procedure or module data contained within MODULENAME _mp_ is the separator between the module and entity names and is always lowercase For example MODULE mymod INTEGER a CONTAINS SUBROUTINE b INTEGER END SUBROU END MODULE FH H u zZ J This results in the following symbols being defined in the compiled o file mymod_mp_a_ mymod_mp_b_ Compiler options can affect
282. rective 36 free form files ee 9 fsource asm compiler option 82 ftz compiler option 55 fverbose asm compiler option 82 fvisibility compiler option 64 fvisibility keyword compiler option 64 G g compiler option 00000 64 89 getting help on compiler options 35 getting started debugging cccceeceeeeeeeeeeeeees 89 EENEG 4 global variables using in mixed language PFOGFAMMMING DE 194 gp compiler option 0 71 guide POW 1O USE eiieeii 3 H help compiler option 64 help on compiler options 35 hexadecimal conversions 240 Hollerith data representation 122 UC logical EE 137 preconnected files 0 151 record UO statement specifiers 158 i_dynamic compiler option 62 i386 preprocessor symbol 25 ia64 preprocessor symbol 25 EC le EEN 6 7 PAS EE 238 IBM keyword ssssssssssssssssserennenese 123 icrt internal map fie 228 icrt link E 228 idb debugger See debugging eeeee 88 IEEE SG floating format 123 IEEE T_floating format 123 IEEE X_floating format 123 Le EE 237 e te ROT 237 ifcore_msg cat file 0 ee 228 ifort command examples of 16 Ehe 14 USING multpie 35 ifort Ar UE 237 238 Leute E 13 Weis Dok 21 237 238 ifortbin file 237 238 IFORTCFG environment variable 13
283. report 0 1 2 sev case cern cs atev axe cateccxesvacave tare cara tev nas teteccxetevecusetexecrts 41 SE WOON OF TI Eeer 41 2810 SID 90 SIO EE 42 vec_report O 1 2 3 4 5 IA 32 systems only 42 warn all or warn NONE OF NOWALN cccceeeceeenneeeeeeeeeeeeceecenteeeeeeeeeeeeeeeeeaaees 43 warn no alignments se eseu EENS eee ee nnn 43 warn Reie ee 43 SWATH NO lCMONS cei a hi Nate Al aaa 43 warn MOTO e 43 Sege 44 warn Bee EE 44 warn no truncated E sacs cain save casein aie enlean 44 warn no uncalled EE 44 Warn NO UNUS BE 45 Warm ele lots gE niia aaea ee reer er ere e 45 KI Reen Ae E E 45 Descriptions of Data OPON oxi ccccccceccerseteceecce cts ceeeestseacey a aai 45 sl ei le EE 45 elle Baler 45 align no Jcommons or align no dcommOonsS ssssennnnnneeeeennnnenneeeeeeennrnnneneeeee 46 Table Of Contents align recnbyte 21 tests ee ek ete th EELER 46 Siet 47 align no sequence scr i 5s cineca etarbanlavelbanlecnepahhaahicelcreabentareibatneubenteceinas 47 assume no byterecl E 47 assume no dummy_aliases en 47 assume no protect_CONStANS ee 48 auto_scalar auto and eave see ecccccessecceceeeceeseceeecaeseceeeeeeeceeeeenseeeeetanes 48 do ple size RE 49 0 5 610169 B Came ce er meee mere 49 integer_size A icicles orale Ar alate liiarale rel alereveceledseatats CeratetssaleleCeemeds 50 SPH decd hc Sus ttt Sal tt ee 50 ah al SIZ64 32 EE 50 Gale Clay EE 51 Rel EE 52 External
284. riding the Default Run Time Library Exception Handler 0 224 Obtaining Traceback Information with TRACEBACKQQ csccccceeeeeeesseeteees 225 Te Le EE Let TEE 226 Using Ra e 226 Libraries Provided by Intel Fortran cccceecceeceeeeeeeeeeeeneeeeeeeeeeeeeeeenneeeeeeeees 226 Portability Eer 227 Portability Library Cepdiew eszegreeteeEESeSAEEEENEIEEEEENSSESEEEEEEEEEEEEUEARESSEEESEEE EEN 227 Using the Portability Library Wbatport a 228 Portability ee 228 Information Retrieval el 228 Process Control en 229 Numeric Values and Conversion Routines EEN 229 Input and Output ROULINGS E 229 Date and Time FOUUINGS E 230 xxi Table Of Contents Error Handling Routines EE 231 System Drive or Directory Control and Inquiry Routines 0 eee 231 Additional Routines EE 231 Math EIERE 231 Reference Information EE 232 Compile Time Environment Variables cccceceeeeeeeeeeeeeeeneeeeeeeeeeeeeeeeeaaees 232 Run Time Environment Variables sssssneeseeeseessennnrnneetnnnrnnreseerrnrnnnnnneeeernnee 233 Key IA 32 Compiler Files Summary EE 235 Key ltanium Based Compiler Files Summary eeeeceeeeeeeeeeeeeeeeeetteeeeeeeees 236 EES 237 Hexadecimal Binary Octal Decimal Conversions sssssssssssnnnnnnnnnnnnnnnnn ennnen 238 Compatibility with Previous Versions of Intel Fortran eeeeeeeeeeeees 239 Differences Between Intel Fortran Version 7 1 and Int
285. rrensseerrrreren 165 Example USEROPEN Program and Function essssssseneeneeeseeeeennnnnneeseereeee 165 Compiling and Linking the C and Intel Fortran Programs sesseeeeeeeen 165 Source Code for the C Function and Header Pie 165 Source Code for the Calling Intel Fortran Program 168 Format of Record NK 169 e Ee UE 169 Variable Length te EE 169 Variable Length Records Less Than 2 Gigabytes sssssseeeeeeeesessrreene 170 Variable Length Records Greater Than 2 Goabwvtes 170 Segmented e ec steel io ereh ieee ysenebleual cone teeeee sheen cieek esos 171 Stream Ee 172 Stream CR and Stream EF ne EE 172 Microsoft Fortran PowerStation Compatible Files 173 Formatted Sequential Piles cciccsss ctccicserisceeuerictecieetcteaseetedscteelttacupsiataceratateee 173 Formatted Direct E 174 Unformatted Sequential FileSscccisccczccceccsscointeiscantcctteoisteinehiecocicosiceiseeencedtacuet 175 Unformatted Direct EE 176 xviii Table Of Contents Programming with Mixed Languages ssssssseeesssesesrerrrenseerrrrnnnnnneserrennn 177 Programming with Mixed Languages OvervieW s sssssssereessssesrrrrrrreeeserrree 177 Calling Subprograms from the Main Program 178 Calls from the Main elen EE 178 Calls to NEE ul AM BEE 179 Summary of Mixed Language Jesues nn 179 Adjusting Calling Conventions in Mixed Language Programming 180 Adjusting Calling Conventions in Mixed Language Programming Overview 181
286. rror 74 Floating underflow FOR IOS_FLTUND During an arithmetic operation a floating point value became less than the smallest finite value for that data type Depending on the values of the fpe noption the underflowed result was either set to zero or allowed to gradually underflow 75 error 75 Floating point exception FOR IOS_SIGFPE A floating point exception occurred Core dump file created Possible causes include e Division by zero e Overflow e Invalid operation such as subtraction of infinite values multiplication of zero by infinity without signs division of zero by zero or infinity by infinity e Conversion of floating point to fixed point format when an overflow prevents conversion 76 error 76 IOT trap signal FOR IOS_SIGIOT Core dump file created Examine core dump for possible cause of this IOT signal 77 severe 77 Subscript out of range FOR IOS_SUBRNG An array reference was detected outside the declared array bounds 78 error 78 Process killed SIGTERM FOR IOS_SIGTERM The process received the signal SIGTERM Determine source of this software termination signal described in signal 3 79 error 79 Process quit SIGQUIT FOR IOS_SIGQUIT The process received the signal SIGQUIT Core dump file created Determine source of this quit signal described in signal 3 95 info 95 Floating point conversion failed FOR IOS_FLOCONFAI The attempted unformat
287. rtran 95 90 pointer arguments in Intel Fortran which are constructed differently than other arguments By default Fortran passes strings by reference along with the string length String length placement depends on whether the compiler option mixed_str_len_arg immediately after the address of the beginning of the string or nomixed_str_len_arg after all arguments is set The default setting is nomixed_str_len_arg Fortran 95 90 array pointers and assumed shape arrays are passed by passing the address of the array descriptor For a discussion of the effect of attributes on passing Fortran 95 90 pointers and strings see Handling Fortran 90 Pointers and Allocatable Arrays and Handling Character Strings Using Common External Data in Mixed Language Programming Common external data structures include Fortran common blocks and C structures and variables that have been declared global or external All of these data specifications create external variables which are variables available to routines outside the routine that defines them External variables are case sensitive so the cases must be matched between different languages as discussed in the section on naming conventions Common external data exchange is described in the following sections e Using Global Variables e Using Fortran Common Blocks and C Structures Using Global Variables in Mixed Language Programming A variable can be shared between Fortran and C by dec
288. rtran RTL searches for the message catalog file at the following location assuming that the default location was chosen during installation 218 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications usr lib ifcore_msg cat However if the environment variable nuspatu is set to point to another location the RTL uses that location to find the message catalog file When using the C shell you can set NLSPATH as follows setenv NLSPATH lt installation path gt N Before executing an Intel Fortran program on a system where Intel Fortran is not installed you need to copy the redistributable files from the appropriate locations specified in the fredist txt file When a run time error occurs on a system where the message file is not found the following messages may appear forrtl info Fortran error message number is nnn forrtl warning Could not open message catalog ifcore_msg cat forrtl info Check environment variable NLSPATH and protection of usr lib ifcore_msg cat The Intel Fortran RTL returns an error number displayed after the severity level that the calling program can use with an IOSTAT variable to handle various I O conditions For more information on nispatu see the reference page environ 5 Values Returned to the Shell at Program Termination An Intel Fortran program can terminate in one of several ways e The program runs to normal completion A v
289. s but has no effect on other interprocedural optimizations Requires ip or ipo ip_no_pinlining IA 32 systems only Default Off Disables partial inlining Requires ip or ipo ipo Default Off Enables Whole Program Optimization WPO which is the same as multifile interprocedural optimization or multifile IPO All objects over the entire program are compiled See also these topics in Volume II Multifile IPO Overview Creating a Multifile IPO Executable with xilink Using Qip with Qoption Specifiers ipo_c Default Off 73 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Optimizes across files and produces a multifile object file Stops prior to the final link stage leaving an optimized object file See also this topic in Volume It Analyzing the Effects of Multifile IPO ipo_obj Default Off Forces the generation of real object files Requires ipo See also this topic in Volume II Compilation with Real Object Files ipo S Default Off Optimizes across files and produces a multifile assembly file Performs the same optimizations as ipo but stops prior to the final link stage leaving an optimized assembly file The default listing name is ipo_out s See also this topic in Volume It Analyzing the Effects of Multifile IPO ivdep_parallel Itanium based systems only Default Off Specifies that there is no loop carried memory dependency in the loop wh
290. s specified by opt ioni1 option2 and so forth to the preprocessor 84 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications This option is the same as fpp except that fpp also invokes fpp Run Time Options The run time options let you specify error checking to be performed at run time not compile time Descriptions of Run Time Options no check all or no check none Default Custom options are specified individually Alternate syntax C is equivalent to check all Specifies all or no checking for run time failures Individual run time check options shown below are not available if check all or check none is specified nocheck is equivalent to check none check is equivalent to check all check noJarg_temp_created Default Custom options are specified individually Default check noarg_temp_created Requests a run time informational message if actual arguments are copied into temporary storage before routine calls check no bounds Default check nobounds Alternate syntax CB Generates code to perform run time checks on array subscript and character substring expressions The default check nobounds suppresses range checking 85 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications For array bounds each individual dimension is checked Array bounds checking is not performed for arrays that are dummy ar
291. s the portability library Libifport a e Call portability routines using the correct parameters and return value libifport a is passed to the linker by default during linking To prevent libifport a from being passed to the linker specify the fpscomp nolibs option Using the 1ibifport a portability library provides interface blocks and parameter definitions for the routines as well as compiler verification of calls Some routines in this library can be called with different sets of arguments and sometimes even as a function instead of a subroutine In these cases the arguments and calling mechanism determine the meaning of the routine The libifport a portability library contains generic interface blocks that give procedure definitions for these routines Fortran 95 90 contains intrinsic procedures for many of the portability functions The portability routines are extensions to the Fortran 95 standard When writing new code use Fortran 95 90 intrinsic procedures whenever possible for portability and performance reasons Portability Routines This section describes some of the portability routines and how to use them For a complete list of the routines see the table of Portability Routines in the Overview chapter of the Intel Fortran Libraries Reference Information Retrieval Routines Information retrieval routines return information about system commands command line arguments environment variables and process or use
292. s using only 4 byte and 8 byte data types in both languages simplifies this or by using the C pack pragmas in the C code around the C structure to make C data packing like Fortran s For example pragma pack 2 struct int N char INFO 30 examp pragma pack To restore the original packing you must add pragma packt atthe end of the structure Remember Fortran module data can be shared directly with C structures with appropriate naming Once you have dealt with alignment and padding you can give C access to an entire common block or set of common blocks Alternatively you can pass individual members of a Fortran common block in an argument list just as you can any other data item Use of common blocks for mixed language data exchange is discussed in the following sections e Accessing Common Blocks and C Structures Directly e Passing the Address of a Common Block Accessing Common Blocks and C Structures Directly You can access Fortran common blocks directly from C by defining an external C structure with the appropriate fields and making sure that alignment and padding between Fortran and C are compatible The C and ALIAS ATTRIBUTES options can be used with a common block to allow mixed case names As an example suppose your Fortran code has a common block named really as shown 195 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications DECS ATTRIBUTES ALIAS Really
293. s for input files temporary files libraries and for the files used by the assembler and the linker use compiler options that specify output file and directory names File Specifications A complete file specification consists of a file name usually preceded by a pathname that specifies a directory The pathname can be in one of two forms e An absolute pathname where the directory is specified relative to the root directory The first character is a slash For example the following directory and file name refer to the file named testdata in the usr users gdata directory usr users gdata testdata e A relative pathname where the specified directory is relative to the current directory Relative pathnames do not begin with a slash The following example uses a relative pathname from the current directory usr users to refer to the same file test data in the gdata subdirectory gdata testdata Directory names and file names should not contain any operating system wildcard characters such as and the construct You can use the tilde character as the first character in a pathname to refer to a top level directory as in the C shell Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications When specifying files keep in mind that trailing and leading blanks are removed from character expression names but not from Hollerith numeric array names File names are case sensitive and can
294. se zeros to terminate strings e The called procedure is type void 210 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications e You must use lowercase names for C routines and INTERFACE blocks to make the calls using lower case Handling User Defined Types Fortran 95 90 supports user defined types data structures similar to C structures User defined types can be passed in modules and common blocks just as other data types but the other language must know the type s structure For example Fortran Code TYPE LOTTA_DATA SEQUENCE REAL A INTEGER B CHARACTER 30 INFO COMPLEX CX CHARACTER 80 MOREINFO END TYPE LOTTA_DATA TYPE LOTTA_DATA D1 D2 COMMON T_BLOCK D1 D2 In the Fortran code above the SEQUENCE statement preserves the storage order of the derived type definition C Code C code accessing D1 and D2 extern struct struct float a int ps char info 30 struct float real imag CX char moreinfo 80 dl d2 LS leck Intel Fortran C Mixed Language Programs 211 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Intel Fortran C Mixed Language Programs Overview See these topics Compiling and Linking Mixed Language Programs Using Modules in Fortran C Mixed Language Programming Calling C Procedures from an Intel Fort
295. severe 28 CLOSE error FOR IOS_CLOERR An error condition was detected by the Intel Fortran RTL I O system during execution of a CLOSE statement 29severe 29 File not found FOR IOS_FILNOTFOU A file with the specified name could not be found during an open operation 30 severe 30 Open failure FOR IOS_OPEFAI An error was detected by the Intel Fortran RTL UO system while attempting to open a file in an OPEN INQUIRE or other I O statement This message is issued when the error condition is not one of the more common conditions for which specific error messages are provided It can occur when an OPEN 245 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications operation was attempted for one of the following e Segmented file that was not on a disk or a raw magnetic tape e Standard I O file that had been closed 31 severe 31 Mixed file access modes FOR IOS_MIXFILACC An attempt was made to use any of the following combinations e Formatted and unformatted operations on the same unit e Aninvalid combination of access modes on a unit such as direct and sequential e A Intel Fortran RTL I O statement on a logical unit that was opened by a program coded in another language 39severe 32 Invalid logical unit number FOR IOS_INVLOGUNI A logical unit number greater than 2 147 483 647 or less than zero was used in an I O statement 33 severe 33 ENDFILE error F
296. sign indicate a sequence of actions For example Click File gt Open indicates that in the File menu click Open to perform this action This type style Bold monospaced text indicates user input Shows what you type as command or input This type style Italic monospaced text indicates placeholders for information that you must supply Italics are also used to introduce new terms options Items inside single square brackets are optional In some examples square brackets are used to show arrays value value Braces and a vertical bar indicate a choice among two or more items You must choose one of the items unless all of the items are also enclosed in square brackets A horizontal ellipsis three dots following an item indicates that the item preceding the ellipsis can be repeated In code examples a horizontal ellipsis means that not all of the statements are shown Microsoft Windows XP An asterisk at the end of a word or name 2 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications indicates it is a third party product trademark Getting Started Getting Started Overview See these topics How You Can Use the Intel Fortran Compiler Compilation Phases Preprocess Phase Assemblers and Linker Default Behavior of the Intel Fortran Compiler Input Files and Filename Extensions File Specifications Output Files
297. sition to the initial position before the first record A sequential access READ or WRITE statement would read or write the first record in the file e BACKSPACE sets the record position to the previous record in a file Using sequential access if you wrote record 5 issued a BACKSPACE to that unit and then read from that unit you would read record 5 e ENDFILE writes an end of file marker This is typically done after writing records using sequential access just before you close the file Unless you use nonadvancing I O reading and writing records usually advances the current record position by one record More than one record might be transferred using a single record I O statement Advancing and Nonadvancing Record ke After you open a file if you omit the ADVANCE specifier or specify ADVANCE YES in READ and WRITE statements advancing I O normal FORTRAN 77 I O will be used for record access When using advancing I O e Record I O statements transfer one entire record or multiple records e Record I O statements advance the current record position to a position before the next record You can request nonadvancing I O for the file by specifying the ADVANCE NO specifier in a READ and WRITE statement You can use nonadvancing I O only for sequential access to external files using formatted I O not list directed or namelist When you use nonadvancing I O the current record position does not change and part of
298. ssigned at run time The second longword bytes 4 to 7 is set to 4 size of a single element The third longword bytes 8 to 11 contain the offset assigned at run time The fourth longword bytes 12 to 15 contains 1 low bit is set The fifth longword bytes 16 to 19 contains 2 rank The sixth longword is reserved The seventh eighth and ninth longwords bytes 24 to 35 contain information for the first dimension as follows o 5 extent o 8 distance between elements o 9 the lower bound e For the second dimension the tenth eleventh and twelfth longwords bytes 36 to 47 contain o 3 extent o 120 distance between elements o 1 the lower bound e Byte 47 is the last byte for this example 8 Note The format for the descriptor on Itanium based systems is identical to that on IA 32 systems except that all fields are 8 bytes long instead of 4 bytes aliellieteicloacl ddef By default Intel Fortran passes a hidden length argument for strings The hidden length argument consists of an unsigned 4 byte integer IA 32 systems or unsigned 8 byte integer Itanium based systems always passed by value added to the end of the argument list You can alter the default way strings are passed by using attributes The following table shows the effect of various attributes on passed strings Effect of ATTRIBUTES Properties on Character Strings Passed as Arguments Argument Default CG C REFERENCE String Passed bv
299. ssing commands such as if define and so forth If you choose to preprocess your source programs you must use the preprocessor fpp which is the preprocessor supplied with the Intel Fortran Compiler or the preprocessing capability of a Fortran compiler It is recommended that you use fpp Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications If you want to use another preprocessor you must invoke it before you invoke the compiler fpp conforms to cpp and accepts the cpp style directives cpp and thus fpp prohibit the use of a string constant value in an i f expression You can use the Preprocessor Options on the command line to direct the operations of the preprocessor A Caution Using a preprocessor that does not support Fortran can damage your Fortran code especially with FORMAT statements For example FORMAT I4 changes the meaning of the program because the backslash indicates end of record Assemblers and Linker The assemblers and linker you can use are summarized in this table Tool Default Provided with Intel Fortran Compiler IA 32 assembler Linux assembler as No ltanium Intel Itanium Yes assembler assembler ias Linker System linker 1d 1 No You can specify alternate tool locations and options for preprocessing compilation assembly and linking See also Libraries Provided by Intel Fortran Assemblers F
300. ssssseeeeeeeeeesene 123 VAXG kevword 123 vec_report compiler option 42 versions of the compiler differences between 240 vms compiler option 38 W w90 compiler option 42 w95 compiler option 42 warn compiler option 42 what compiler option 20 64 WI compiler option 64 WRITE statement ADVANCE specifier 2 161 WRITE statement 138 139 147 158 X x compiler option 006 64 71 Ee 237 238 291 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications ENEE 237 238 Z Xlinker option 64 zero compiler option 47 Y Zp compiler option 47 y compiler option 64 292
301. statement in greater detail For example OPEN UNIT 4 FILE usr users smith test dat STATUS OLD The file test dat in directory usr users smith is opened on logical unit 4 No defaults are applied because both the directory and file name were specified The value of the FILE specifier can be a character constant variable or expression In the following interactive example the user supplies the file name and the DEFAULTFILE specifier supplies the default values for the full pathname string The file to be opened is in usr users smith and is concatenated with the file name typed by the user into the variable DOC CHARACTER LEN 9 DOC WRITE 6 Type file name READ 5 DOC OPEN UNIT 2 FILE DOC DEFAULTFILE usr users smith STATUS OLD A slash is appended to the end of the default file string if it does not have one Obtaining File Information INQUIRE Statement The INQUIRE statement returns information about a file and has three forms e Inquiry by unit e Inquiry by file name e Inquiry by output item list Inquiry by Unit 153 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications An inquiry by unit is usually done for an opened connected file An inquiry by unit causes the Intel Fortran RTL to check whether the specified unit is connected or not One of the following occurs depending on whether the
302. stdin ACCEPT f iolist FOR_ACCEPT FORT5 stdin WRITE f iolist FOR_PRINT FORT6 stdout PRINT f iolist FOR_PRINT FORT6 stdout TYPE f iolist FOR_TYPE FORT6 stdout You can change the file associated with these Intel Fortran environment variables as you would any other environment variable by means of the environment variable assignment command For example setenv FOR _READ usr users smith test dat After executing the preceding command the environment variable for the READ statement using an asterisk refers to file test dat in directory usr users smith Default Pathnames and File Names Intel Fortran provides the following possible ways of specifying all or part of a file specification directory and file name such as usr proj testdata e The FILE specifier in an OPEN statement typically specifies only a file name such as testdata or contains both a directory and file name such as usr proj testdata e The DEFAULTFILE specifier in an OPEN statement typically specifies a pathname that contains only a directory such as usr proj or both a directory and file name such as usr proj testdata e lf you used an implied OPEN or if the FILE specifier in an OPEN statement did not specify a file name you can use an environment variable to specify a file name or a pathname that contains both a directory and file name 148 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Ap
303. sult in a number of bytes that exceeds the maximum record length RECL the Intel Fortran RTL attempts to increase the RECL value and write the longer record To obtain the RECL value use an INQUIRE statement e For list directed output and namelist output if the data specified exceeds the maximum record length RECL another record is written 162 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications User Supplied OPEN Procedures USEROPEN Specifier You can use the USEROPEN specifier in an Intel Fortran OPEN statement to pass control to a routine that directly opens a file The called routine can use system calls or library routines to open the file and establish special context that changes the effect of subsequent Intel Fortran I O statements The Intel Fortran RTL I O support routines call the USEROPEN function in place of the system calls usually used when the file is first opened for I O The USEROPEN specifier in an OPEN statement specifies the name of a function to receive control The called function must open the file or pipe and return the file descriptor of the file when it returns control to the RTL When opening the file the called function usually specifies options different from those provided by a normal OPEN statement You can obtain the file descriptor from the Intel Fortran RTL for a specific unit number with the get fd routine Although the called function can be writ
304. t to set up 14 FUP HUMIC eegen eg r g eegent 234 SEENEN 13 VIEWING E 13 EOR branch specifier 222 ERR branch specifier 222 error handling el 216 run time a tinnctiocinneisedtarsatecarnattes 222 error handling secssticteic tt sect toctenctes 217 error handling capabilities OPEN statement specifiers for 152 error handling routines 230 error messages PUTING este ee 242 Error PFOCESSING eseeeeeeeeeeeees 217 error_limit compiler option 42 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications ERRSNS subroutine aaaaannnnn 222 example program SQUARES Et 95 exception handler for Run Time Library RTL overriding cceeeeeeeeeeees 226 EXCEPTION_CONTINUE_SEARCH E 234 exceptional numbers identifying iy sectecvotevenventeinernseress 119 exchanging data in mixed language programming ee 191 executable program creating running and cebugging export Commande 13 expressions in debugger commande 106 extend_source compiler option 60 EXTENDED PRECISION data representation c60e 117 extensions Dlename ccc cecccccceeeceeeeeeeeeeeeeeess 9 external procedures options 54 270 F F_UFMTENDIAN environment variable bereet 130 234 F_UFMTENDIAN method 130 f66 compiler option 60 f77rtl compiler optton 38 f90_dyncom run time l
305. t variables to specify locations for the various components 12 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications The Intel Fortran Compiler installation includes a shell script that you can use to set environment variables Use the source command to execute the shell script from the command line For example to execute this script file for the bash shell source opt intel_fc_ 80 bin ifortvars sh If you use the C shell use the csh version of this script file source opt intel_fc_ 80 bin ifortvars csh lf you want ifortvars sh to run automatically when you start Linux edit your bash_profile file and add the line above to the end of your file For example set up environment for Intel compiler source opt intel_fc_80 bin ifortvars sh Invoking the Intel Fortran Compiler You can invoke the Intel Fortran Compiler in either of two ways e Using the ifort command e Using the make command to specify a makefile Using the ifort Command The syntax is ifort options input_file s An option is specified by one or more letters preceded by a hyphen Some options take arguments in the form of filenames strings letters or numbers Except where otherwise noted you can enter a space between the option and its argument s or you can combine them See Compiler Options Overview You can specify more than one input_file using a space as a delimiter See Input Files and Filename
306. table resides 20 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications However if you want the compiler to use another configuration file in a different location you can use the IFORTCFG environment variable to assign the directory and file name for the other configuration file Example Configuration File An example configuration file is shown below The pound character indicates that the rest of the line is a comment Example ifort cfg file Define preprocessor macro MY_PROJECT DMY_PROJECT Set extended length source lines extend_source D Set maximum floating point significand precision pc80 Response Files You can use response files also known as indirect command files to e Specify options used during particular compilations for particular projects e Save this information in individual files Response files are invoked as an option on the command line Options specified in a response file are inserted in the command line at the point where the response file is invoked Like configuration files response files are used to e Decrease the time you spend entering command line options e Ensure consistency of often used commands However options in a configuration file are executed every time you run the compiler In contrast you use response files to maintain options for individual projects You can place any numb
307. tatement 24 severe 24 End of file during read FOR IOS_ENDDURREA One of the following conditions occurred A Intel Fortran RTL UO system end of file condition was encountered during execution of a READ statement that did not contain an END ERR or IOSTAT specification An end of file record written by the ENDFILE statement was encountered during execution of a Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications READ statement that did not contain an END ERR or lIOSTAT specification e An attempt was made to read past the end of an internal file character string or array during execution of a READ statement that did not contain an END ERR or IOSTAT specification This error is returned by END and ERRSNS 25 severe 25 Record number outside range FOR IOS_ RECNUMOUT A direct access READ WRITE or FIND statement specified a record number outside the range specified when the file was opened 26severe 26 OPEN or DEFINE FILE required FOR IOS_OPEDEFREQ A direct access READ WRITE or FIND statement was attempted for a file when no prior DEFINE FILE or OPEN statement with ACCESS DIRECT was performed for that file 97 severe 27 Too many records in I O statement FOR IOS_TOOMANREC An attempt was made to do one of the following e Read or write more than one record with an ENCODE or DECODE statement e Write more records than existed 28
308. ted Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications read or write of nonnative floating point data failed because the floating point value e Exceeded the allowable maximum value for the equivalent native format and was set equal to infinity plus or minus e Was infinity plus or minus and was set to infinity plus or minus e Was invalid and was set to not a number NaN Very small numbers are set to zero 0 This error could be caused by the specified nonnative floating point format not matching the floating point format found in the specified file Check the following e Whether the correct file was specified e Whether the record layout matches the format Intel Fortran is expecting e The ranges for the data being used e Whether the correct nonnative floating point data format was specified Q6info 96 F_UFMTENDIAN environment variable was ignored erroneous syntax FOR IOS_UFMTENDIAN Syntax for specifying whether little endian or big endian conversion is performed for a given Fortran unit was incorrect Even though the program will run the results might not be correct if you do not change the value of F_UFMTENDIAN For correct syntax see Environment Variable F_LUFMTENDIAN Method 108 severe 108 Cannot stat file FOR IOS_CANSTAFIL Attempted stat operation on the indicated file failed Make sure correct file and unit were specified 120 severe 120 Opera
309. tement accesses the module ARRAY_CALCULATOR This module contains the function declaration for CALC_AVERAGE The 5 element array is passed to the function CALC_AVERAGE which returns the value to the variable AVERAGE for printing The example is File main COU This program calculates the average of five numbers PROGRAM MAIN USE ARRAY _CALCULATOR REAL DIMENSION 5 A 0 REAL AVERAGE PRINT Type five numbers READ F10 3 A AVERAGE CALC_AVERAGE A PRINT Average of the five numbers is AVERAGE END PROGRAM MAIN The example below shows the module referenced by the main program This example program shows more Fortran 95 90 features including an interface block and an assumed shape array File array_calc f90 Module containing various calculations on arrays MODULE ARRAY_CALCULATOR INTERFACE FUNCTION CALC_AVERAGE D REAL CALC_AVERAGE REAL INTENT IN D END FUNCTION CALC_AVERAGE END INTERFACE Other subprogram interfaces END MODULE ARRAY_CALCULATOR The example below shows the function declaration CALC_AVERAGE referenced by the main program File calc_aver f90 External function returning average of array FUNCTION CALC_AVERAGE D REAL CALC AVERAGE REAL INTENT IN D CALC_AVERAGE SUM D UBOUND D DIM 1 END FUNCTION CALC_AVERAGE
310. tements on sequential files e ERR specifies a label to branch to if an error occurs e lOSTAT specifies an integer variable to contain the error number if an error occurs e FMT specifies a label of a FORMAT statement or character data specifying a FORMAT e NML specifies the name of a NAMELIST e REC specifies a record number for direct access When using nonadvancing I O use the ADVANCE EOR and SIZE specifiers When using the REWRITE statement you can use the UNIT FMT ERR and IOSTAT specifiers Record Access Record access refers to how records will be read from or written to a file regardless of the file s organization Record access is specified each time you open a file it can be different each time The type of record access permitted is determined by the combination of file organization and record type For instance you can e Add records to a sequential file with ORGANIZATION SEQUENTIAL and POSITION APPEND or use ACCESS APPEND e Add records sequentially by using multiple WRITE statements close the file and then open it again with ORGANIZATION SEQUENTIAL and ACCESS SEQUENTIAL or ACCESS DIRECT if the sequential file has fixed length records Sequential Access 157 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Sequential access transfers records sequentially to or from files or I O devices such as terminals You can use sequential
311. ten in other languages such as Fortran C is usually the best choice for making system calls such as open or create Syntax and Behavior of the USEROPEN Specifier The USEROPEN specifier for the OPEN statement has the form USEROPEN function name function name represents the name of an external function In the calling program the function must be declared in an EXTERNAL statement For example the following Intel Fortran code might be used to call the USEROPEN procedure UOPEN known to the linker as uopen_ EXTERNAL UOPEN INTEGER UOPEN OPEN UNIT 10 FILE usr test data STATUS NEW USEROPEN UOPEN 163 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications During the OPEN statement the uopen_ function receives control The function opens the file may perform other operations and subsequently returns control with the file descriptor to the RTL If the USEROPEN function is written in C declare it as a C function that returns a 4 byte integer int result to contain the file descriptor For example int uopen_ 1 char file name 2 int open_flags 3 int create_mode 4 int ens 5 int file_length 6 The function definition and the arguments passed from the Intel Fortran RTL are as follows 1 The function must be declared as a 4 byte integer int 2 The first argument is the pathname includes the file name to be opened 3 The open fl
312. th any value of fpen Intrinsic function FP_CLASS helps to find and replace denormalized numbers with zeroes before the program can attempt to perform calculations on the denormalized numbers On the other hand if this program did not replace denormalized numbers read from unit 1 with zeroes and the program was compiled with fpeo then the first attempted calculation on a denormalized number would result in a floating point exception File fordef for and intrinsic function FP_CLASS can work together to identify NaNs A variation of the previous example would contain the symbols for_k_fp_snan and for_k_fp_qnan in the IF statement A faster way to do this is based on the intrinsic function ISNAN One modification of the previous example using ISNAN follows The ISNAN function does not need file fordef for real 4 a 100 open an unformatted file as unit 1 read 1 a do i 1 100 if isnan a i then print Element i contains a NaN end if end do close 1 end You can compile this program with any value of fpen 119 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Character Representation A character string is a contiguous sequence of bytes in memory as shown below CHAR 1 A GHAR L Aal ZK 0 E A character string is specified by two attributes the address A of the first byte of the string and the length L of the string in bytes The length L of a strin
313. th too many or too few subscripts for the variable e An attempt was made to specify a substring of a noncharacter variable or array name e A substring specifier of the character variable was out of bounds Applications 243 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications 244 20 severe A subscript or substring specifier of the variable was not an integer constant An attempt was made to specify a substring by using an unsubscripted array variable 20 REWIND error FOR IOS_REWERR One of the following conditions occurred The file was not a sequential file The file was not opened for sequential or append access The Intel Fortran RTL I O system detected an error condition during execution of a REWIND statement 91 severe 21 Duplicate file specifications FOR IOS_DUPFILSPE Multiple attempts were made to specify file attributes without an intervening close operation A DEFINE FILE statement was followed by another DEFINE FILE statement or an OPEN statement oosevere 22 Input record too long FOR IOS_INPRECTOO A record was read that exceeded the explicit or default record length specified when the file was opened To read the file use an OPEN statement with a RECL value record length of the appropriate size 93 severe 23 BACKSPACE error FOR IOS_BACERR The Intel Fortran RTL I O system detected an error condition during execution of a BACKSPACE s
314. the called routine In a mixed language program different languages cannot share the same header files If as a result you link Fortran and C routines that use different calling conventions the error is not apparent until the bad call is made at run time During execution the bad call causes indeterminate results and or a fatal error often somewhere in the program that has no apparent relation to the actual cause memory stack corruption due to calling errors Therefore you should check carefully the calling conventions for each mixed language call The discussion of calling conventions between languages applies only to external procedures You cannot call internal procedures from outside the program unit that contains them A calling convention affects programming in four ways 1 The caller routine uses a calling convention to determine the order in which to pass arguments to another routine the called routine uses a calling convention to determine the order in which to receive the arguments passed to it In Fortran you can specify these conventions in a mixed language interface with the INTERFACE statement or in a data or function declaration C C and Fortran both pass arguments in order from left to right 2 The caller routine and the called routine use a calling convention to select the option of passing a variable number of arguments 3 The caller routine and the called routine use a calling convention to pass arguments by va
315. the Fortran COMPLEX types struct complex4 float real imag struct complexs double real imag D I A Fortran LOGICAL 2 is stored as a 2 byte indicator value O false and the fpscomp no logicals compiler option determines how true values are handled A Fortran LOGICAL 4 is stored as a 4 byte indicator value and LOGICAL 1 is stored as a single byte The type LOGICAL is the same as LOGICAL 4 which is equivalent to type int in C You can use a variable of type LOGICAL in an argument list module common block or global variable in Fortran and type int in C for the same argument Type LOGICAL 4 is recommended instead of the shorter variants for use in common blocks The Intel C class type has the same layout as the corresponding C struct type unless the class defines virtual functions or has base classes Classes that lack those features can be passed in the same way as C structures Returning Complex Type Data 199 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications If a Fortran program expects a procedure to return a COMPLEX DOUBLE COMPLEX value the Fortran compiler adds an additional argument to the beginning of the called procedure argument list This additional argument is a pointer to the location where the called procedure must store its result Example below shows the Fortran code for returning a complex data type procedure called WBAT and the corresponding
316. the file to be computed correctly For relative files the layout and overhead of fixed length records depend on whether or not the program accessing the file was compiled with the vms option For relative files where the vms option was omitted the default each record has no control information For relative files where the vms option was specified each record has one byte of control information at the beginning of the record The figure below shows the record layout of fixed length records For all sequential files and for relative files where the yms option was omitted Peco length REC Lewa For relative files where the yms option was specified Im It Record length RRECL value 2K 9819 GE Variable Length Records 169 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Variable length records can contain any number of bytes up to a specified maximum record length and apply only to sequential files Variable length records are prefixed and suffixed by 4 bytes of control information containing length fields The trailing length field allows a BACKSPACE request to skip back over records efficiently The 4 byte integer value stored in each length field indicates the number of data bytes excluding overhead bytes in that particular variable length record The character count field of a variable length record is available when you read the record b
317. the naming of module data and procedures Note 188 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Except for ALIAS ATTRIBUTES properties do not affect the module name The following table shows how each ATTRIBUTES property affects the subroutine in the previous example module Effect of ATTRIBUTES Options on Fortran Module Names ATTRIBUTES Property Given to Procedure Name in o file Routine b None mymod_mp_b_ C mymod_mp_b_ ALIAS Overrides all others name as given in the alias VARYING No effect on name You can write code to call Fortran modules or access module data from other languages As with other naming and calling conventions the module name must match between the two languages Generally this means using the C convention in Fortran and if defining a module in another language using the ALIAS property to match the name within Fortran For examples see Using Modules in Fortran C Mixed Language Programming Prototyping a Procedure in Fortran You define a prototype interface block in your Fortran source code to tell the Fortran compiler which language conventions you want to use for an external reference The interface block is introduced by the INTERFACE statement See Program Units and Procedures in the Language Reference for a description of the INTERFACE statement The general form for the INTERFACE statement is INTERFACE routine statement routine A
318. the parallelizer tool libguide so libguide_stats a Support for parallelizer tool with performance and profile libguide_stats Sso jnformation libifcore a Intel specific Fortran run time library libifcore so libifcore so 5 libifcoremt a Multithreaded Intel specific Fortran run time library libifcoremt so libifcoremt so 5 libifport a Portability and POSIX support libifport so libifport so 5 libimf a Math library libimf so libirc a Intel specific library optimizations libircmt a Multithreaded Intel specific library optimizations libompstub a Library that resolves references to OMP subroutines when OMP is not in use libsvml a Short vector math library libunwind a Unwind support libunwind so libunwind so 5 Portability Library Portability Library Overview Intel Fortran includes functions and subroutines that ease porting of code to or from a PC or allow you to write code on a PC that is compatible with other platforms The portability library is called 1ibifport a Frequently used functions are included in a portability module called IFPORT See these topics Using the Portability Library libifport a 227 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Portability Routines Using the Portability Library libifport a You can use the portability library 1ibifport a in one of two ways e Add the statement USE IFPORT to your program This statement include
319. ting system F Note This document explains how information and instructions apply differently to each targeted architecture If there is no specific indication to either architecture the description is applicable for both architectures Additional Documentation Besides the two volumes of the User s Guide you should also have access to these manuals e Intel Fortran Compiler Options Quick Reference Guide for Linux Systems e Intel Fortran Language Reference Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications e Intel Fortran Libraries Reference e Intel Fortran Release Notes Notation Conventions This manual uses the following conventions Intel Fortran The name of the common compiler language supported by the Intel Visual Fortran Compiler for Windows and Intel Fortran Compiler for Linux products This type style Elements of syntax reserved words option keywords variables file names and code examples are shown in a monospaced font The text appears in lowercase unless uppercase is required THIS TYPE STYLE Statements keywords and directives are shown in all uppercase in a normal font For example add the USE statement This type style Bold normal text shows menu names menu items button names dialog window names and other user interface items File gt Open Menu names and menu items joined by a greater than gt
320. tion 62 STATUS specifier in OPEN statement 143 Std compiler option 42 std90 comnpiler opiton 42 std95 compiler option 42 storage big endian e 123 little endian 2cc ccccmeccsesexyerscconet 123 stream Te 170 stream record type 144 146 Stream_CR record 170 Stream_CR record type 144 146 Stream_LF record aecsceisnseceneenn 170 Stream_LF record type 144 146 Streaming SIMD Extensions SSE 5 Streaming SIMD Extensions 2 SSE2 RE 5 STRICT compiler directive 36 subprograms calling from the main program 180 summary of mixed language issues 180 symbol predefined preprocessor 25 symbol table information 89 syntax compiler option 64 syntax_only compiler option 64 289 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications system drive or directory control and inquiry routines 230 T T compiler option e 64 TBK_ENABLE_VERBOSE_STACK__ TRACE environment variable 234 TBK_FULL_SRC_FILE SPEC environment variable 234 TEMP environment variable 11 234 Tf compiler option 64 threads compiler option 62 TMP environment variable 11 234 TMPDIR environment variable 11 234 tool ele 23 tools passing options To 23 tpp compiler option
321. tion of the record with blank spaces The blanks ensure that the file contains only completely filled records all of the same length During input the compiler by default also pads the input if the input list and format require more data than the record contains You can override the default blank padding on input by setting PAD NO in the OPEN statement for the file If PAD NO the input record must contain the amount of data indicated by the input list and format specification Otherwise an error occurs PAD NO has no effect on output An example of a program writing two records record one and record three to a formatted direct file is given below The result is shown in the following figure 174 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications OPEN 3 FILE FDIR FORM FORMATTED ACCESS DIRECT RECL 10 WRITE 3 A10 REC 1 RECORD ONE WRITE 3 15 REC 3 30303 CLOSE 3 END Formatted Direct File 10 bytes data 2 bytes CR LF separator 12 bytes undefined data 5 bytes data T bytes padding blank e bytes CR LF separator 10 111213 22 i 24 2529 1 36 hetro Ll Biel 2 ae Bi cA K Ll Biel 2 Ka Se 8338 Bi cA QA L Record 1 L L Racons Unformatted Sequential Files Unformatted sequential files are organized slightly differently on different platforms This section describes unformatted sequential files c
322. tion requires seek ability FOR IOS_OPEREQSEE Attempted an operation on a file that requires the ability to perform seek operations on that file Make sure the correct unit directory path and file were specified 253 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications 138 severe 138 Array index out of bounds SIGILL FOR IOS_BRK_RANGE Break exception generated a SIGTRAP signal described in signal 3 Core dump file created The cause is an array subscript that is outside the dimensioned boundaries of that array Either recompile with the check bounds option perhaps with the decfort_dump_flag environment variable set or examine the core dump file to determine the source code in error 139 severe 139 Array index out of bounds for index nn SIGILL FOR IOS_ BRK_RANGE2 Break exception generated a SIGTRAP signal described in signal 3 Core dump file created The cause is an array subscript that is outside the dimensioned boundaries of the array index n Either recompile with the check bounds option perhaps with the decfort_dump_flag environment variable set or examine the core dump file to determine the source code in error 140 severe 140 Floating inexact FOR IOS_FLTINE A floating point arithmetic or conversion operation gave a result that differs from the mathematically exact result This trap is reported if the rounded result of an IEEE operation
323. tions Naming Conventions for Fortran C and C Reconciling the Case of Names Fortran Module Names and ATTRIBUTES C C Naming Conventions C and C preserve case sensitivity in their symbol tables while Fortran by default does not a difference that requires attention Fortunately you can use the Fortran directive ATTRIBUTES ALIAS option to resolve discrepancies between names to preserve mixed case names or to override the automatic conversion of names to all lowercase by Fortran C uses the same calling convention and argument passing techniques as C but naming conventions differ because of C decoration of external symbols When the C code resides in a cpp file created when you select C C file from the integrated development environment C name decoration semantics are applied to external names often resulting in linker errors The extern C syntax makes it possible for a C module to share data and routines with other languages by causing C to drop name decoration The following example declares prn as an external function using the C naming convention This declaration appears in C source code extern C void prn To call functions written in Fortran declare the function as you would in C and use a C linkage specification For example to call the Fortran function FACT from C declare it as follows extern C int FACT int n The extern C syntax can be used to adjust a call from C
324. to add K K 1 after line 10 as shown Compiler assigned line numbers have been added to clarify the example 15 The revised program is compiled and linked The shell command idb squares Starts the debugger using the revised program so that its correct execution can be verified 16 The when at 12 print k command reports the value of K at each iteration through the loop 17 The run command starts execution 18 The displayed values of K confirm that the program is running correctly 19 The quit command ends the debugging session returning control to the shell 97 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Displaying Variables in the Debugger To refer to a variable use either the uppercase or lowercase letters For example idb print J idb print j You can enter command names in uppercase idb print J If you compile the program with the command line option names as_is and you need to examine case sensitive names you can control whether idb is case sensitive by setting the 1ang environment variable to the name of a case sensitive language Module Variables To refer to a variable defined in a module insert an opening quote the module name and another opening quote before the variable name For example with a variable named J defined in a module named modfile statement MODULE MODFILE enter the following command to display its value
325. to get a complete list of these abbreviations and even create your own aliases The table below shows examples of the most commonly used debugger commands For more information see the online Intel Debugger IDB Manual Command Description example catch Displays all signals that the debugger is currently set to catch See also ignore catch fpe Tells the debugger to catch the fpe signal or the signal specified This prevents the specified signal from reaching the Intel Fortran run time library RTL Caren Tells the debugger to catch the unaligned signal unaligned cont Resumes continues execution of the program that is being debugged Note that there is no idb command named continue delete 2 Removes the breakpoint or tracepoint identified by event number 2 See also status delete all Removes all breakpoints and tracepoints help Displays debugger help text history 5 Displays the last five debugger commands ignore Displays the signals the debugger is currently set to ignore The ignored signals are allowed to pass directly to the Intel Fortran RTL See also catch ignore fpe Tells the debugger to ignore the fpe signal or the signal specified This allows the specified signal to pass directly to the Intel Fortran RTL allowing message display ignore unaligned Tells the debugger to ignore the unaligned signal the default kill Terminates th
326. to other languages or to change the naming convention of C routines called from other languages However extern C can only be used from within C If the C code does not use extern C and cannot be changed you can call C routines only by determining the name decoration and generating it from the other language 186 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Such an approach should only be used as a last resort because the decoration scheme is not guaranteed to remain the same between versions Use of extern C has some restrictions e You cannot declare a member function with extern C e You can specify extern C for only one instance of an overloaded function all other instances of an overloaded function have C linkage Procedure Names in Fortran C and C The following table summarizes how Fortran C and C handle procedure names Language Attributes Name Translated As Case of Name in O File Fortran cDEC name_ All lowercase ATTRIBUTES C Fortran default name _ All lowercase C cdec1 default name_ Mixed case preserved C stdcall _hame n Mixed case preserved C Default _name decoration Mixed case preserved Reconciling the Case of Names The following summarizes how to reconcile names between languages e All lowercase names If the name of the routine appears as all lowercase in C then naming conventions are automatically cor
327. to the local myabort routine program aborts integer i call clear_signal i 3 if i lt 5 then call myabort end if end Obtaining Traceback Information with TRACEBACKQQ You can obtain traceback information in your application by calling the TRACEBACKQQ routine TRACEBACKQQ allows an application to initiate a stack trace You can use this routine to report application detected errors use it for debugging and so on It uses the standard stack trace support in the Intel Fortran run time system to produce the same output that the run time system produces for unhandled errors and exceptions severe error message The TRACEBACKQQ subroutine generates a stack trace showing the program call stack as it was leading up to the point of the call to TRACEBACKQQ The error message string normally included from the run time support is replaced with the user supplied message text or omitted if no user string is specified Traceback output is directed to the target destination appropriate for the application type just as it is when traceback is initiated internally by the run time support In the most simple case a user can generate a stack trace by coding the call to TRACEBACKQQ with no arguments 220 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications CALL TRACEBACKQQ This call causes the run time library to generate a traceback report with no leading header message fr
328. two step commands continue executing the program into the loop lines 9 to 11 that copies and squares all nonzero elements of INARR into OUTARR Certain commands can be abbreviated In this example the s command is an abbreviation of the step command 9 The command print i k displays the current values of variables I and K Variable I has the expected value 1 But variable K has the value 0 instead of the expected value 1 To fix this error K should be incremented in the loop just before it is used in line 11 10 The assign command assigns K the value 1 11 The watch variable k command sets a watchpoint that is triggered every time the value of variable K changes In the original version of the program this watchpoint is never triggered indicating that the value of variable K never changes a programming error 12 To test the patch the cont command an abbreviation of continue resumes execution from the current location The program output shows that the patched program works properly but only for the first array element Because the watchpoint watch variable k command does not occur the value of K did not change and there is a problem The idb message Process has exited with status 0 shows that the program executed to completion 13 The quit command returns control to the shell so that you can correct the source file and recompile and relink the program 14 The shell command vi runs a text editor and the source file is edited
329. u Can Use the Intel Fortran Compiler cccceeeeeeeeeeeeeeeeeeeeeeeeeeneees 3 Compilation Phases iaicteac ict hatte tied tet ease ieietta eats tats i ee felts et 4 Preprocess ne 5 Assemblers and RE 6 ASSOMBIGIS ESO 6 le 7 Default Behavior of the Intel Fortran Compiler 7 Input Files and Filename Extensions en 7 let Le 8 DEER 9 Temporary Files Created by the Compiler or Linker ssseeeseseeeeeeeeees 10 Building EIERE EE 10 Building Applications Overview EE 10 Controlling the Compilation Process ESA 11 Setting and Viewing Environment Variables eesssssseeeeeeeeseeeenrrnnnrensserrrrrnnn n 11 Table Of Contents Configuration File Environment Variables sssseeseeeeeseeeeenennrnresserrrnrrrnneeeee 12 Running the Shell Script to Set Up the Environment Vartables 12 Invoking the Intel Fortran Compiler ccccceceeeeeeeeeeeeeeeeeeeeeeeecneeeeeeeeeeeeeeeenaaees 13 Using the ifort ein rn EE 13 Using the make CGommand ENEE 14 Examples of the UGEREEST ln lek a ede 14 Compiling and Linking Multiple Files cceeeeeeeeeeeeeeeeeeeeenneeeeeeeeeeeeeeeeeeanees 14 PRE VEMUMG WE Lulu EE 14 Compiling Fortran 95 90 and C Source ies 15 Renaming the EIER 15 Specifying an Additional Linker Library ccceeeeeeeeeeeeeeeeneeeeeeeeeeeeeeeeeaeees 15 Using Module mod UE 16 Compiling Programs with Modules AEN 16 Working with Multi Directory Module Files
330. u can write a partial record to an unformatted direct file Intel Visual Fortran pads these records to the fixed record length with ASCII NULL characters Unwritten records in the file contain undefined data The following program creates the sample unformatted direct file shown in the following figure OPEN 3 FILE UFDIR RECL 10 amp amp FORM UNFORMATTED ACCESS DIRECT WRITE 3 REC 3 TRUE abcdef WRITE 3 REC 1 2049 CLOSE 3 END Unformatted Direct File 4 bytes for integer value 2049 6 undefined bytes zeros in Microsoft Fortran 10 bytes undefined data 4 bytes for logical value TRUE 6 bytes for character value abcdef 30 1 45 1011 20 21 24 25 Hex Hex ASCII ai 08 aa a0 1 08 00 00 abcdef L Record 1 L Record L Record 3 Programming with Mixed Languages Programming with Mixed Languages Overview Mixed language programming is the process of building programs in which the source code is written in two or more languages It allows you to e Call existing code that is written in another language e Use procedures that may be difficult to implement in a particular language e Gain advantages in processing speeds 177 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Mixed language programming is possible between Intel Fortran and Intel C To properly create mixed language programs rules
331. ult Fortran passes all data by reference except the hidden length argument of strings which is passed by value If the ATTRIBUTES C option is used the default changes to passing all data by value except arrays If the procedure has the REFERENCE option as well as the C option all arguments by default are passed by reference In Fortran in addition to establishing argument passing with the calling convention option C you can specify argument options VALUE and REFERENCE to pass arguments by value or by reference In mixed language programming it is a good idea to specify the passing technique explicitly rather than relying on defaults S Note In addition to ATTRIBUTES the no mixed_str_len_arg compiler option also establishes some default argument passing conventions such as for hidden length of strings Examples of passing by reference and value for C follow All are interfaces to the example Fortran subroutine TEstproc below The definition of resteroc declares how each argument is passed The REFERENCE option is not strictly necessary 191 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications in this example but using it makes the argument s passing convention conspicuous SUBROUTINE TESTPROC VALPARM REFPARM DECS ATTRIBUTES VALUE VALPARM DECS ATTRIBUTES REFERENCE REFPARM INTEGER VALPARM INTE
332. unit is connected or not If the unit is connected e The EXIST and OPENED specifier variables indicate a true value e The pathname and file name are returned in the NAME specifier variable if the file is named e Other information requested on the previously connected file is returned e Default values are usually returned for the INQUIRE specifiers also associated with the OPEN statement e The RECL value unit for connected formatted files is always 1 byte units For unformatted files the RECL unit is 4 byte units unless you specify the assume byterecl option to request 1 byte units If the unit is not connected e The OPENED specifier indicates a false value e The unit NUMBER specifier variable is returned as a value of 1 e Any other information returned will be undefined or default values for the various specifiers 0 For example the following INQUIRE statement shows whether unit 3 has a file connected OPENED specifier in logical variable OPENED the name case sensitive in character variable _ NAME and whether the file is opened for READ WRITE or READWRITE access in character variable ACTION NQUIRE 3 OPENED I_OPENED NAME I_NAME ACTION I_ACTION Inquiry by File Name An inquiry by name causes the Intel Fortran RTL to scan its list of open files for a matching file name One of the following occurs depending on whether a match occurs or not If a matc
333. uration files 0 eeeee 21 controlling compilation Drorcess 13 conventions documentation BE 3 conversions 266 hexadecimal binary octal decimal eher eege 240 convert compiler option 38 converting unformatted data EIER eege 123 CRAY kevwond 123 Cray style pointer 99 203 creating executable program 27 shared libraries nn 30 ORO WIG ainaani 228 Cu De EE 228 cxxlib icc compiler option 62 D d_lines compiler option 60 data unaligned ele ee esses is ee es ei 108 data alignment compiler options Tor 47 data format specifying compiler option convert method eege kee 135 environment variable COMPLEVIa 119 F_UFMTENDIAN method 130 EIERE 118 environment variable FORT_CONVERT ext method DOUBLE COMPLEX 118 Ween 129 DOUBLE PRECISION 116 environment variable FORT_CONVERT_ext EXTENDED PRECISION 117 method soci e ee 129 ele e E 122 environment variable FORT_CONVERTn method ai Ge EE 109 eebe 128 leie Ter WEE 114 OPEN statement CONVERT INGUNOG oian ari 133 native IEEE floating point representation ssseeneeee 115 OPTIONS statement method134 OVEFV EW EE 109 le Le ln E 127 eege 116 NR Let 47 REAL KIND 16 cceccceees 117 data prefetching ssssseeeeeessereeee 5 REAL KIND 4 0 cccceeeeeees 116 data representation HEALIRIND 21 116 character EE 121 data storage EE 2
334. urce position to inlined code no logo Default logo startup banner is displayed 65 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Displays the startup banner This option can be placed anywhere on the command line The startup banner displays the following information e ID unique identification number for the compiler e x y z version of the compiler e years years for which the software is copyrighted nofor_main Default Off Specifies that the main program is not written in Fortran For example if the main program is written in C and calls an Intel Fortran subprogram specify nofor_main when compiling the program with the ifort command Specifying nofor_main prevents linking Cor main o into programs This is a link time switch If you omit nofor_main the main program must be a Fortran program noinclude Default Off Prevents the compiler from searching in usr include for files specified in an INCLUDE statement You can specify the Idir option along with this option This option does not affect cpp 1 behavior and is not related to the Fortran 95 and 90 USE statement no pad Default nopad Enables the changing of the variable and array memory layout The paad option is effectively not different from align when applied to structures and derived types However the scope of pad is greater because it applies also to common blocks deri
335. use C to perform the file open and close as well as all record operations call the appropriate C procedure from the Intel Fortran program without using the Fortran OPEN statement Restrictions of Called USEROPEN Functions The Intel Fortran RTL uses exactly one file descriptor per logical unit which must be returned by the called function Because of this only certain system calls or library routines can be used to open the file System calls and library routines that do not return a file descriptor include mknod see mknod 2 and fopen see fopen 3 For example the fopen routine returns a file pointer instead of a file descriptor Example USEROPEN Program and Function The following Intel Fortran code calls the USEROPEN function named UOPEN EXTERNAL UOPEN INTEGER UOPEN OPEN UNIT 1 FILE exl dat STATUS NEW USEROPEN UOPEN ERR 9 IOSTAT errnum If the default ifort options are used the external name is passed using lowercase letters with an appended trailing underscore _ In the preceding example the external function UOPEN would be known as uopen_ to the linker and must be declared in C as uopen_ Compiling and Linking the C and Intel Fortran Programs Use a single ifort command to compile the called uopen_ C function uopen_ c and the Intel Fortran calling program ex1 The same command also links both object files by using the appropriate libraries to create the file a out file as f
336. utable program or remove traceback and symbol table information with the strip command See strip 1 Using the help option to the compiler indicates g only Note Debugging of optimized code is not fully supported on Intel platforms Preparing Your Program for Debugging 88 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Use the ifort command with certain options to create an executable program for debugging To invoke the debugger enter the debugger shell command and the name of the executable program The following commands create compile and link the executable program and invoke the interface to the debugger ifort g o squares squares f90 idb squares Linux Application Debugger for xx bit applications Version x X Build xxxx object file name squares reading symbolic information done idb In this example the ifort command e Compiles and links the program squares f90 e Requests symbol table information needed for symbolic debugging and no optimization g e Names the executable file squares instead of a out Lo squares The idb shell command runs the debugger specifying the executable program squares At the debugger prompt idb you can enter a debugger command See also the online nte Debugger IDB Manual Using Debugger Commands and Setting Breakpoints To find out what happens at critical points in your program you need
337. vars sh Setup file for bash shell profdcg profmerge proforder tselect uninstall sh Uninstall utility Xlar xild Applications Executable used by the compiler Utility used for Profile Guided Optimizations Utility used for Profile Guided Optimizations Test prioritization tool Tool used for Interprocedural Optimizations Tool used for Interprocedural Optimizations For a list of files installed in 1ib see Libraries Provided by Intel Fortran Compiler Limits The amount of data storage the size of arrays and the total size of executable programs are limited only by the amount of process virtual address space available as determined by system parameters The table below shows the limits to the size and complexity of a single Intel Fortran program unit and to individual statements contained within it Language Element Limit Actual number of arguments per CALL or function reference Limited only by memory constraints Arguments in a function reference 255 in a specification expression Array dimensions 7 Array construction nesting 20 Array elements per dimension 9 223 372 036 854 775 807 2 31 1 on IA 32 systems 2 63 1 Itanium based systems plus limited by current memory configuration Constants character and Hollerith 7198 characters Constants characters read in list directed I O 2048 characters Continuation lines 511 Data and I O implied DO nesting 7 DO and b
338. vecssnacevsennsies 242 FOR IOS_SYNERRFOR error e GE 242 FOR IOS_SYNERRNAM error Ee E 242 FOR IOS_TOOMANREC error Ke EE 242 FOR IOS_TOOMANVAL error INGSSAQS is see EES 242 FOR IOS_UFMTENDIAN error MT e nnnnennarenseennnrnna renerne 242 FOR IOS_UNFIO_FMT error WNSSSACC Secathneska beet eege deer 242 FOR IOS_UNIALROPE error WS e E 242 FOR IOS_UNINOTCON error Messageri mpa a S 242 FOR IOS_WRIREAFIL error MOSSAQC wee ae EA 242 FOR_ACCEPT environment variable FOR_DIAGNOSTIC_LOG_FILE environment variable 234 FOR_DISABLE_DIAGNOSTIC_DIS PLAY environment variable 234 FOR_DISABLE_STACK_TRACE environment variable 234 FOR_IGNORE_EXCEPTIONS environment variable 234 FOR_K_FP_NEG_DENORM symbol VEER EE e 119 FOR_K_FP_NEG_INF symbol 119 FOR_K_FP_NEG_NORM symbol ed 119 FOR_K_FP_NEG_ZERO symbol 119 FOR_K_FP_POS_DENORM symbol E ATT 119 Index FOR_K_FP_POS_INF symbol 119 FOR_K_FP_POS_NORM symbol FOR_K_FP_POS_ZERO symbol 119 FOR_K_FP_QNAN symbol 119 FOR_K_FP_SNAN symbol 119 Tor main ole 228 FOR_NOERROR_DIALOGS environment variable 234 FOR_PRINT environment variable Ee 234 FOR_READ environment variable EE 234 FOR_TYPE environment variable See 234 fordef for file E 119 FORM specifier in OPEN statement 139 147 format of record types ceeeeeeee 170 FORMAT statement and preproc
339. ved types sequence types and structures prec_div lA 32 systems only 66 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications Default Off Enables improved precision of floating point divides Has a slight impact on speed rcd IA 32 systems only Default Off Enables changing of rounding mode for float to integer conversions resulting in faster float to integer conversions size_ p64 Itanium based systems only Default Off Specifies that 64 bit size for long and pointer types should be assumed no stack_temps Default Off Specifies that arrays might be allocated on the stack where possible by the compiler nostartfiles Default Off Specifies that standard startup files should be used when linking There is no start files option syntax_only Default Off Alternate syntax y and syntax Requests that only the syntax of the source file be checked Code generation is suppressed T file Default Off 67 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications Instructs the linker to read link commands from file Tf file Default Off Specifies that filename should be compiled as a Fortran source file This option is used when you have a Fortran file with a nonstandard file extension that is not one of F FOR or F90 U Default Off Alternate syntax implicitnone Specifies that the IMPLICIT NONE
340. ware error e Request of another program e When a process is stopped to allow access to the control terminal You can optionally set certain events to issue signals for example e When a process resumes after being stopped e When the status of a child process changes e When input is ready at the terminal Some signals terminate the receiving process if no action is taken optionally creating a core file while others are simply ignored unless the process has requested otherwise Except for certain signals calling the signal Or sigaction routine allows specified signals to be ignored or causes an interrupt transfer of control to the location of a user written signal handler You can establish one of the following actions for a signal with a call to signa1 e Ignore the specified signal identified by number 223 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications e Use the default action for the specified signal which can reset a previously established action e Transfer control from the specified signal to a procedure to receive the signal specified by name Calling the signa routine lets you change the action for a signal such as intercepting an operating system signal and preventing the process from being stopped The table below shows the signals that the Intel Fortran RTL arranges to catch when a program is started Signal Intel Fortran RTL mess
341. wing e Arrays are not accessed out of arrays bounds e Pointers are not cast to non pointer types and vice versa e References to objects of two different scalar types cannot alias For example an object of type integer cannot alias with an object of type real or an object of type real cannot alias with an object of type double precision If your program satisfies the above conditions setting the ansi_alias option will help the compiler optimize the program However if your program might not satisfy any of the above conditions you must disable this option with ansi_alias as it might cause the compiler to generate incorrect code assume cc OD Default depends on whether openmp is specified Enables conditional compilation as defined by the OpenMP Fortran API When Sspace appears in free form source or Sspaces appears in column 1 of fixed form source the rest of the line is accepted as a Fortran line If openmp is specified the default is assume cc_omp otherwise the default is assume nocc_omp assume none Turns off all the assume options nobss _ init Default Off Disables placement of zero initialized variables in the BSS section By default variables explicitly initialized with zeros are placed in the BSS section By using this option you can place any variables that are explicitly initialized with zeros in the DATA section if required There is no bss_init option 63 Intel Fortran
342. with array bounds checking a run time error message appears When you run SQUARES it produces the following output regardless of the number of nonzero elements in the data file squares Number of nonzero elements is 0 94 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building Applications The logic error occurs because variable K which keeps track of the current index into OUTARR is not incremented in the loop on lines 9 through 13 The statement K K 1 should be inserted just before line 11 The following example shows how to start the debugging session and how to use the character cell interface to idb to find the error in the sample program shown earlier Comments keyed to the callouts at the right follow the example ifort g o squares squares f90 1 idb squares 2 Linux Application Debugger for xx bit applications Version x X Build xxxx object file name squares reading symbolic information done idb list 1 9 3 il PROGRAM SQUARES 2 NTEGER INARR 20 OUTARR 20 3 C Read the input array from the data file gt 4 OPEN UNIT 8 FILE datafile dat STATUS OLD 5 READ 8 END 5 N INARR I I 1 N 6 5 CLOSE UNIT 8 7 C Square all nonzero elements and store in OUTARR 8 K 0 9 DO 10 I 1 N idb stop at 8 4 1 stop at squares f90 8
343. x point to the right of the most significant bit Fractions are assumed to be normalized and therefore the most significant bit is not stored this is called hidden bit normalization This bit is assumed to be 1 unless the exponent is 0 If the exponent equals 0 then the value represented is denormalized subnormal or plus or minus zero Intrinsic REAL kinds are 4 single precision 8 double precision and 16 extended precision such as REAL KIND 4 for single precision floating point data Intrinsic COMPLEX kinds are also 4 single precision 8 double precision and 16 extended precision To obtain the kind of a variable use the KIND intrinsic function You can also use a size specifier such as REAL 4 but be aware this is an extension to the Fortran 95 standard If you omit certain compiler options the default sizes for REAL and COMPLEX data declarations are as follows e For REAL data declarations without a kind parameter or size specifier the default size is REAL KIND 4 same as REAL 4 113 Intel Fortran Compiler for Linux Systems User s Guide Volume Building Applications e For COMPLEX data declarations without a kind parameter or size specifier the default data size is COMPLEX KIND 4 same as COMPLEX 8 To control the size of all REAL or COMPLEX declarations without a kind parameter use the real_size 64 0r real_size 128 options the default is real_size 32 You can explicitly declare the
344. y nnn message text where e forrtl identifies the source as the Intel Fortran RTL e severity identifies the severity level severe error warning Or info e nnn identifies the message number also the IOSTAT value for I O statements e message text explains the event that caused the message The severity levels are described in order of greatest to least severity e A severe message must be corrected The program s execution is terminated when the error is encountered unless the program s I O statements use the END EOR or ERR branch specifiers to transfer control perhaps to a routine that uses the IOSTAT specifier e Anerror message should be corrected The program might continue execution but the output from this execution may be incorrect e Awarning message should be investigated The program continues execution but output from this execution may be incorrect e An info message is for informational purposes only The program continues For severe errors stack trace information is produced by default unless the environment variable FoR_DISABLE_STACK_TRACE is set If the command line option t raceback is set the stack trace information contains program counters set to symbolic information Otherwise the information contains merely hexadecimal program counter information In some cases stack trace information is also produced by the compiled code at run time to provide details about the creation of array t
345. y issuing a READ statement with a Q format descriptor You can then use the count field information to determine how many bytes should be in an I O list Variable Length Records Less Than 2 Gigabytes The figure below shows the record layout of variable length records that are less than 2 gigabytes Trailing User Data Length Field 4 _ Record length RECL value _ _ 4 2K o820 0E Variable Length Records Greater Than 2 Gigabytes For a record length greater than 2 147 483 639 bytes the record is divided into subrecords The subrecord can be of any length from 1 to 2 147 483 639 inclusive The sign bit of the leading length field indicates whether the record is continued or not The sign bit of the trailing length field indicates the presence of a preceding subrecord The position of the sign bit is determined by the endian format of the file A subrecord that is continued has a leading length field with a sign bit value of 1 The last subrecord that makes up a record has a leading length field with a sign bit value of 0 A subrecord that has a preceding subrecord has a trailing length field with a sign bit value of 1 The first subrecord that makes up a record has a trailing length field with a sign bit value of 0 The figure below shows the record layout of variable length records that are greater than 2 gigabytes 170 Intel Fortran Compiler for Linux Systems User s Guide Volume l Building
346. y or include it in the shared library being created You can specify multiple object o files when creating a shared library To put a routine in a separate shared library obtain the source or object file for that routine recompile if necessary and create a separate shared library You can specify an object file when recompiling with the ifort command or when creating the shared library with the 1a command To include a routine in the shared library being created put the routine source or object file with other source files that make up the shared library and recompile if necessary Then create the shared library making sure that you specify the file containing that routine either during recompilation or when creating the shared library You can specify an object file when recompiling with the ifort command or when creating the shared library with the 14 command e When creating shared libraries all symbols must be defined resolved Because all symbols must be defined to 1a when you create a shared library you must specify the shared libraries on the 1a command line including all standard Intel Fortran libraries unless you use the Qoption command The list of standard Intel Fortran libraries might be specified by using the 1string option Installing Shared Libraries Once the shared library is created it must be installed for private or system wide use before you run a program that refers to it e To install a private shared libr

Intel® Fortran Compiler for Linux* Systems User's Guide, Volume I

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Intel&reg; Fortran Compiler for Linux* Systems User's Guide, Volume I

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Intel® Fortran Compiler for Linux* Systems User's Guide, Volume I