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.

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

IA-32, Intel® EM64T, Itanium®-based?

Description

__INTEL_COMPILER=n

On, n=900

All

Identifies the Intel Fortran Compiler

__INTEL_COMPILER_BUILD_DATE
=YYYYMMDD

 

All

Identifies the Intel Fortran Compiler build date

__linux__
__linux
__gnu_linux__
linux
__unix__
__unix
unix
__ELF__
 

 

All

Defined at the start of compilation

__i386__
__i386
i386

 

IA-32

Identifies the architecture for the target hardware for which programs are being compiled

__ia64__
__ia64
ia64

 

Itanium®

Identifies the architecture for the target hardware for which programs are being compiled

__x86_64
__x86_64__

 

Intel® EM64T

Identifies the architecture for the target hardware for which programs are being compiled.

_OPENMP=n

n=200011

All

Takes 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 when -openmp is specified.

_PGO_INSTRUMENT

Off

All

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.

Preprocessing replaces every occurrence of the defined symbol name with the specified value.

For more information, see the following topic:

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.

For more information, see the following topic: