Mercurial > hg > octave-lyh > gnulib-hg
changeset 16318:39ff0ed6c426
stdalign: check that alignof and offsetof are consistent
* m4/stdalign.m4 (gl_STDALIGN_H): Check for GCC bug 52023.
Problem reported for gnulib by Richard W.M. Jones in
<http://lists.gnu.org/archive/html/bug-gnulib/2012-01/msg00340.html>.
author | Paul Eggert <eggert@cs.ucla.edu> |
---|---|
date | Fri, 27 Jan 2012 10:17:18 -0800 |
parents | c38ba07a30d1 |
children | 934a441c5452 |
files | ChangeLog m4/stdalign.m4 |
diffstat | 2 files changed, 21 insertions(+), 1 deletions(-) [+] |
line wrap: on
line diff
--- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,10 @@ +2012-01-27 Paul Eggert <eggert@cs.ucla.edu> + + stdalign: check that alignof and offsetof are consistent + * m4/stdalign.m4 (gl_STDALIGN_H): Check for GCC bug 52023. + Problem reported for gnulib by Richard W.M. Jones in + <http://lists.gnu.org/archive/html/bug-gnulib/2012-01/msg00340.html>. + 2012-01-27 Jim Meyering <meyering@redhat.com> update-copyright: accept new option: UPDATE_COPYRIGHT_USE_INTERVALS=2
--- a/m4/stdalign.m4 +++ b/m4/stdalign.m4 @@ -14,13 +14,26 @@ [AC_COMPILE_IFELSE( [AC_LANG_PROGRAM( [[#include <stdalign.h> - int align_int = alignof (int) + _Alignof (double); + #include <stddef.h> + + /* Test that alignof yields a result consistent with offsetof. + This catches GCC bug 51316 + <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51316>. */ + #ifdef __cplusplus + template <class t> struct alignof_helper { char a; t b; }; + # define ao(type) offsetof (alignof_helper<type>, b) + #else + # define ao(type) offsetof (struct { char a; type b; }, b) + #endif + char test1[_Alignof (double) == ao (double) ? 1 : -1]; + char test2[alignof (long int) == ao (long int) ? 1 : -1]; /* Test _Alignas only on platforms where gnulib can help. */ #if \ (__GNUC__ || __IBMC__ || __IBMCPP__ \ || 0x5110 <= __SUNPRO_C || 1300 <= _MSC_VER) int alignas (8) alignas_int = 1; + char test3[8 <= _Alignof (alignas_int) ? 1 : -1]; #endif ]])], [gl_cv_header_working_stdalign_h=yes],