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\begin{fortranspecific}[4ex]
\section{Fortran Comments (Fixed Source Form)}
\label{sec:fortran_fixed_format_comments}
\index{directive syntax!fixed form, Fortran}
\index{fixed form syntax, Fortran}

OpenMP directives in Fortran codes with fixed source form are specified as comments with one of the
\scode{!$omp}, \scode{c$omp}, and \scode{*$omp} sentinels, followed by a
directive name, and required and optional clauses.  The sentinel must begin in column 1.

In the example below the first directive (DIR 1) specifies the %parallel work-sharing 
\kcode{parallel do} combined directive, with a \kcode{num_threads} clause, and a comment.
The second directive (DIR 2) shows the same directive split
across two lines. The next nested directives (DIR 3 and 4) show the previous combined directive as
two separate directives. 
Here, an \kcode{end} directive (\kcode{end parallel}) must be specified to demarcate the range (region)
of the \kcode{parallel} directive.

\fnexample{directive_syntax_F_fixed_comment}{1}
\end{fortranspecific}
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