Parallelization directives explicitly request the compiler attempt to parallelize the DO loop that follows the directive. The syntax differs from general directives. Parallelization directives are only recognized when compilation options --parallel or --explicitpar are used. (f77 parallelization options are described in the Fortran User's Guide.)
Parallelization directives have the following syntax:
The first character must be in column one.
The first character can be any one of c, C, *, or !.
The next four characters are $PAR, no blanks, either upper or lower case.
Next follows the directive keyword and options, separated by blanks.
The explicit parallelization directive keywords are:
TASKCOMMON, DOALL, DOSERIAL, and DOSERIAL*
Each parallelization directive has its own set of optional qualifiers that follow the keyword.
C$PAR DOALL SHARED(yvalue)
See the Fortran Programming Guide for details about parallelization and these directives.