Mercurial > hg > octave-kai > gnulib-hg
changeset 17375:7524d97ae56f
stdalign: port to stricter ISO C11
ISO C11 says that _Alignof's operand must be a parenthesized type.
Problem reported by Eli Zaretskii in
<http://lists.gnu.org/archive/html/emacs-devel/2013-03/msg00960.html>.
* doc/posix-headers/stdalign.texi (stdalign.h): Document this.
* m4/stdalign.m4 (gl_STDALIGN_H): Don't use _Alignof (expr).
author | Paul Eggert <eggert@cs.ucla.edu> |
---|---|
date | Fri, 29 Mar 2013 19:47:13 -0700 |
parents | 5a51fb7777a9 |
children | 79877e369ef2 |
files | ChangeLog doc/posix-headers/stdalign.texi m4/stdalign.m4 |
diffstat | 3 files changed, 19 insertions(+), 2 deletions(-) [+] |
line wrap: on
line diff
--- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,12 @@ +2013-03-29 Paul Eggert <eggert@cs.ucla.edu> + + stdalign: port to stricter ISO C11 + ISO C11 says that _Alignof's operand must be a parenthesized type. + Problem reported by Eli Zaretskii in + <http://lists.gnu.org/archive/html/emacs-devel/2013-03/msg00960.html>. + * doc/posix-headers/stdalign.texi (stdalign.h): Document this. + * m4/stdalign.m4 (gl_STDALIGN_H): Don't use _Alignof (expr). + 2013-03-21 Paul Eggert <eggert@cs.ucla.edu> sys_select, sys_time: port 2013-01-30 Solaris 2.6 fix to Cygwin
--- a/doc/posix-headers/stdalign.texi +++ b/doc/posix-headers/stdalign.texi @@ -25,6 +25,13 @@ Portability problems not fixed by Gnulib: @itemize @item +In ISO C11, the operand of @code{alignof}/@code{_Alignof} must be a +parenthesized type. Recent versions of GCC support an extension in +which the operand can also be a unary expression, as with +@code{sizeof}. We don't know of any compilers that support +@code{alignof}/@code{_Alignof} without also supporting this extension; +if you find one please let us know. +@item @code{_Alignas} and @code{alignas} are not always supported; on platforms lacking support, the macro @code{__alignas_is_defined} is not defined.
--- a/m4/stdalign.m4 +++ b/m4/stdalign.m4 @@ -33,8 +33,9 @@ #if \ (__GNUC__ || __IBMC__ || __IBMCPP__ \ || 0x5110 <= __SUNPRO_C || 1300 <= _MSC_VER) - int alignas (8) alignas_int = 1; - char test_alignas[_Alignof (alignas_int) == 8 ? 1 : -1]; + struct alignas_test { char c; char alignas (8) alignas_8; }; + char test_alignas[offsetof (struct alignas_test, alignas_8) == 8 + ? 1 : -1]; #endif ]])], [gl_cv_header_working_stdalign_h=yes],