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.x.

Intel® Fortran supports extensions to the ISO and ANSI standards, including a number of extensions defined by:

• Intel Fortran for various platforms

• 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.x

Some differences are:

• 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.x, these command names will still be accepted, but in some future Intel Fortran release, only the ifort command name will be accepted.

• The default configuration file name is now ifort.cfg instead of ifl.cfg or efl.cfg.

• The predefined symbol name for the Intel Fortran compiler is __INTEL_COMPILER and it has a value of 800 for Intel Fortran Version 8.0 and 810 for Intel Fortran Version 8.1.

• 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.

• 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.

• Intel Fortran Version 8.x 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.x, the compiler will use the integer 1 for the value of .TRUE..
  Version 8.x 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.

• The random number generator used in Version 8.x 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 Compaq 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.x 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.

Documentation Information

Some documentation has been moved. In particular:

• The Intel Fortran User’s Guide now has separate parts for Building Applications and Optimizing Applications.

• Intel Fortran language information previously described in the Intel Fortran Programmer’s Reference, including intrinsics procedures and directives, is now described in the online Language Reference.

• 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 Fortran Version 8.x

The following Intel Fortran Version 7.1 features are not  available in Intel Fortran Version 8.x:

• IMPLICIT AUTOMATIC | STATIC statements

• The Intel Fortran 8.x run-time library system's ability to work with the Itanium processor simulator