When browsing libgomp doc, I came across
https://gcc.gnu.org/onlinedocs/libgomp/Enabling-OpenMP.html
First, I found especially the Fortran part difficult to read. Secondly,
it missed the C++ attribute syntax. And I also missed a reference to
-fopenmp-simd.
The attached patch tries to improve this. Note that it talks about C and
C++ attributes, even though C23's [[omp::]] support has not yet landed.
(But is expected very soon.)
I also do not try to list what -fopenmp-simd supports as that's at
https://gcc.gnu.org/onlinedocs/gcc/C-Dialect-Options.html#index-fopenmp
and I bet we won't keep both in sync and "man gcc" is more likely to be
up to date.
Comments?
Tobias
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libgomp.texi: Update "Enabling OpenMP"
libgomp/
* libgomp.texi (Enabling OpenMP): Update for C/C++ attributes;
improve wording especially for Fortran; mention -fopenmp-simd.
diff --git a/libgomp/libgomp.texi b/libgomp/libgomp.texi
index 526d1be2955..d8126f96fe4 100644
--- a/libgomp/libgomp.texi
+++ b/libgomp/libgomp.texi
@@ -136,15 +136,22 @@ changed to GNU Offloading and Multi Processing Runtime Library.
@node Enabling OpenMP
@chapter Enabling OpenMP
-To activate the OpenMP extensions for C/C++ and Fortran, the compile-time
-flag @command{-fopenmp} must be specified. This enables the OpenMP directive
-@code{#pragma omp} in C/C++ and @code{!$omp} directives in free form,
-@code{c$omp}, @code{*$omp} and @code{!$omp} directives in fixed form,
-@code{!$} conditional compilation sentinels in free form and @code{c$},
-@code{*$} and @code{!$} sentinels in fixed form, for Fortran. The flag also
-arranges for automatic linking of the OpenMP runtime library
+To activate the OpenMP extensions for C/C++ and Fortran, the compile-time
+flag @command{-fopenmp} must be specified. For C and C++, this enables
+the handling of the OpenMP directives using @code{#pragma omp} and the
+@code{[[omp::directive(...)]]}, @code{[[omp::sequence(...)]]} and
+@code{[[omp::decl(...)]]} attributes. For Fortran, it enables for
+free source form the @code{!$omp} sentinel for directives and the
+@code{!$} conditional compilation sentinel and for fixed source form the
+@code{c$omp}, @code{*$omp} and @code{!$omp} sentinels for directives and
+the @code{c$}, @code{*$} and @code{!$} conditional compilation sentinels.
+The flag also arranges for automatic linking of the OpenMP runtime library
(@ref{Runtime Library Routines}).
+The @command{-fopenmp-simd} flag can be used to enable a subset of
+OpenMP directives, which do not require the linking of neither the
+OpenMP runtime library nor the POSIX threads library.
+
A complete description of all OpenMP directives may be found in the
@uref{https://www.openmp.org, OpenMP Application Program Interface} manuals.
See also @ref{OpenMP Implementation Status}.
