Setting Run-Time Environment Variables

The Intel® Fortran run-time system recognizes a number of environment variables. These variables can be used to customize run-time diagnostic error reporting, allow program continuation under certain conditions, disable the display of certain dialog boxes under certain conditions, and allow just-in-time debugging. For a list of run-time environment variables used by OpenMP*, see OpenMP Environment Variables in Optimizing Applications.

For information on setting compile time environment variables, see Setting Compile-Time Environment Variables.

The run-time environment variables are:

• 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.

• 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.

• 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 CONIN$ (standard input). If FOR_ACCEPT is defined (as a file name optionally containing a path), the specified file would be read.

• FOR_DEBUGGER_IS_PRESENT 
  This variable tells the Fortran run-time library that your program is executing under a debugger. If set to True, it generates debug exceptions whenever severe or continuous errors are detected. Under normal conditions you don't need to set this variable on Windows systems, as this information can be extracted from the operating system. On Linux* and Mac OS* systems, you will need to set this variable if you want debug exceptions. Setting this variable to True when your program is not executing under a debugger will cause unpredictable behavior.

• FOR_DEFAULT_PRINT_DEVICE (Windows* only)
  This variable lets you specify the print device other than the default print device PRN (LPT1) for files closed (CLOSE statement) with the DISPOSE='PRINT' specifier. To specify a different print device for the file associated with the CLOSE statement DISPOSE='PRINT' specifier, set FOR_DEFAULT_PRINT_DEVICE to any legal DOS print device before executing the program.

• 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_FILE is independent of FOR_DISABLE_DIAGNOSTIC_DISPLAY, so you can disable the screen display of information but still capture the error information in a file. 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.
  See also Locating Run-Time Errors.

• FOR_DISABLE_DIAGNOSTIC_DISPLAY
  This variable disables the display of all error information. This variable is  helpful if you just want to test the error status of your program and do not want the Fortran run-time system to display any information about an abnormal program termination.
  

• 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. If the program is executing under a debugger, the automatic output of the stack trace information by the Fortran library will be disabled to reduce noise. You should use the debugger's stack trace facility if you want to view the stack trace.
  See also Locating Run-Time Errors.

• 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.

• 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.

• FOR_PRINT
  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 or WRITE (*,f) iolist writes to CONOUT$ (standard output). If FOR_PRINT is defined (as a file name optionally containing a path), the specified file would be written to.

• 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 or READ f,iolist reads from CONIN$ (standard input). If FOR_READ is defined (as a file name optionally containing a path), the specified file would be read.

• 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 CONOUT$ (standard output). If FOR_TYPE is defined (as a file name optionally containing a path), the specified file would be written to.

• 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 the -assume buffered_io (Linux*) or /assume:buffered_io (Windows*) compiler option.

• FORT_CONVERTn
  Lets you specify the data format for an unformatted file associated with a particular unit number (n), as described in Methods of Specifying the Data Format.

• FORT_CONVERT.ext and FORT_CONVERT_ext
  Lets you specify the data format for unformatted files with a particular file extension suffix (ext), as described in Methods of Specifying the Data Format.

• FORT_FMT_RECL
  Lets you specify the default record length (normally 132 bytes) for formatted files.

• FORT_UFMT_RECL
  Lets you specify the default record length (normally 2040 bytes) for unformatted files.

• 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 (Linux) or /fpscomp:filesfromcmd (Windows) was not specified. Preconnected files attached to units 0, 5, and 6 are by default associated with system standard I/O files.

• NLSPATH (Linux* and Mac OS* only)
  The path for the Intel Fortran run-time error message catalog.

• 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 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* Visual Fortran.
  

• TBK_FULL_SRC_FILE_SPEC
  By default, the traceback output displays only the file name and extension in the source file field. To display complete file name information including the path, set the environment variable TBK_FULL_SRC_FILE_SPEC to true.
  The variable FOR_FULL_SRC_FILE_SPEC is also recognized for compatibility with Compaq* Visual Fortran.
  

• TMP, TMPDIR, and TEMP
  Specifies an alternate working directory where temporary files are created. See Temporary Files Created by the Compiler or Linker.

Setting Environment Variables within a Program

You can set a run-time environment variable from within a program by calling the SETENVQQ routine. For example:

program ENVVAR

use ifport

LOGICAL(4) res  

! Add other data declarations here

! call SETENVQQ as a function  

res=SETENVQQ("FOR_IGNORE_EXCEPTIONS=T")