[Bug fortran/34928] Extension: volatile common blocks

[dominiq at lps dot ens.fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34928

--- Comment #10 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
Bud,

Will the following patch be good enough before closing this PR as WONTFIX?

--- ../_clean/gcc/fortran/gfortran.texi    2014-01-04 15:51:42.000000000 +0100
+++ gcc/fortran/gfortran.texi    2014-02-03 15:33:50.000000000 +0100
@@ -1990,6 +1990,7 @@ code that uses them running with the GNU
 @c * CARRIAGECONTROL, DEFAULTFILE, DISPOSE and RECORDTYPE I/O specifiers::
 @c * Omitted arguments in procedure call::
 * Alternate complex function syntax::
+* Volatile COMMON blocks::
 @end menu


@@ -2184,6 +2185,18 @@ extensions.  @command{gfortran} accepts 
 common, but not the former.


+@node Volatile COMMON blocks
+@subsection Volatile @code{COMMON} blocks
+@cindex @code{VOLATILE}
+@cindex @code{COMMON}
+
+Some Fortran compilers, including @command{g77}, let the user declare
+@code{COMMON} with the @code{VOLATILE} attribute. This is
+invalid standard Fortran 77/90/95/2003/2008 syntax and is not
+supported by @command{gfortran}. Note that @command{gfortran} accepts
+VOLATILE variables in COMMON blocks since revision 4.3.
+
+

 @c ---------------------------------------------------------------------
 @c Mixed-Language Programming