layout | title | release_number | author | tutorial |
---|---|---|---|---|
tutorial_page |
OpenMP Directives: Fortran Directive Format |
UCRL-MI-133316 |
Blaise Barney, Lawrence Livermore National Laboratory |
OpenMP |
sentinel | directive-name | [clause ...] |
---|---|---|
All Fortran OpenMP directives must begin with a sentinel. The accepted sentinels depend upon the type of Fortran source. Possible sentinels are: !$OMP C$OMP *$OMP |
A valid OpenMP directive must appear after the sentinel and before any clauses. | Optional. Clauses can be in any order, and repeated as necessary unless otherwise restricted. |
!$OMP PARALLEL DEFAULT(SHARED) PRIVATE(BETA,PI)
-
!$OMP
C$OMP
*$OMP
are accepted sentinels and must start in column 1. -
All Fortran fixed form rules for line length, white space, continuation and comment columns apply for the entire directive line.
-
Initial directive lines must have a space/zero in column 6.
-
Continuation lines must have a non-space/zero in column 6.
-
!$OMP
is the only accepted sentinel. Can appear in any column, but must be preceded by white space only. -
All Fortran free form rules for line length, white space, continuation and comment columns apply for the entire directive line.
-
Initial directive lines must have a space after the sentinel.
-
Continuation lines must have an ampersand as the last non-blank character in a line. The following line must begin with a sentinel and then the continuation directives.
-
Comments can not appear on the same line as a directive.
-
Only one directive-name may be specified per directive.
-
Fortran compilers which are OpenMP enabled generally include a command line option which instructs the compiler to activate and interpret all OpenMP directives.
-
Several Fortran OpenMP directives come in pairs and have the form shown below. The "end" directive is optional but advised for readability.
!$OMP <directive > [ structured block of code ] !$OMP end <directive >