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\section{Fortran Comments (Fixed Source Form)}
\label{sec:fortran_fixed_format_comments}

OpenMP directives in Fortran codes with fixed source form are specified as comments with one of the
\code{!\$omp}, \code{c\$omp}, and \code{*\$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 
\code{parallel}~\code{do} combined directive, with a \code{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 \code{end} directive (\code{end}~\code{parallel}) must be specified to demarcate the range (region)
of the \code{parallel} directive.

\fexample{directive_syntax_F_fixed_comment}{1}
