From: Bruno Haible Date: Fri, 8 Sep 2017 08:02:47 +0000 (+0200) Subject: stddef: Avoid conflict with system-defined max_align_t. X-Git-Tag: v1.0~5955 X-Git-Url: https://gitweb.git.savannah.gnu.org/gitweb/?a=commitdiff_plain;h=3ba4dbaefe671991083ff46a2714ff256adf75a1;p=gnulib.git stddef: Avoid conflict with system-defined max_align_t. The configure-determined HAVE_MAX_ALIGN_T may not always be accurate. Reported by Werner Lemberg in . * lib/stddef.in.h (rpl_max_align_t): Renamed from max_align_t. (max_align_t): Define as a macro. (GNULIB_defined_max_align_t): New macro. Guards against multiple definitions of rpl_max_align_t in different copies of gnulib-generated . --- diff --git a/ChangeLog b/ChangeLog index 63eb16db07..68d3205019 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,15 @@ +2017-09-08 Bruno Haible + + stddef: Avoid conflict with system-defined max_align_t. + The configure-determined HAVE_MAX_ALIGN_T may not always be accurate. + Reported by Werner Lemberg in + . + * lib/stddef.in.h (rpl_max_align_t): Renamed from max_align_t. + (max_align_t): Define as a macro. + (GNULIB_defined_max_align_t): New macro. Guards against multiple + definitions of rpl_max_align_t in different copies of gnulib-generated + . + 2017-09-05 Paul Eggert libc-config: port to MSVC diff --git a/lib/stddef.in.h b/lib/stddef.in.h index 2a11d2b71d..a79f5363df 100644 --- a/lib/stddef.in.h +++ b/lib/stddef.in.h @@ -85,24 +85,28 @@ a hack in case the configure-time test was done with g++ even though we are currently compiling with gcc. */ #if ! (@HAVE_MAX_ALIGN_T@ || defined _GCC_MAX_ALIGN_T) +# if !GNULIB_defined_max_align_t /* On the x86, the maximum storage alignment of double, long, etc. is 4, but GCC's C11 ABI for x86 says that max_align_t has an alignment of 8, and the C11 standard allows this. Work around this problem by using __alignof__ (which returns 8 for double) rather than _Alignof (which returns 4), and align each union member accordingly. */ -# ifdef __GNUC__ -# define _GL_STDDEF_ALIGNAS(type) \ - __attribute__ ((__aligned__ (__alignof__ (type)))) -# else -# define _GL_STDDEF_ALIGNAS(type) /* */ -# endif +# ifdef __GNUC__ +# define _GL_STDDEF_ALIGNAS(type) \ + __attribute__ ((__aligned__ (__alignof__ (type)))) +# else +# define _GL_STDDEF_ALIGNAS(type) /* */ +# endif typedef union { char *__p _GL_STDDEF_ALIGNAS (char *); double __d _GL_STDDEF_ALIGNAS (double); long double __ld _GL_STDDEF_ALIGNAS (long double); long int __i _GL_STDDEF_ALIGNAS (long int); -} max_align_t; +} rpl_max_align_t; +# define max_align_t rpl_max_align_t +# define GNULIB_defined_max_align_t 1 +# endif #endif # endif /* _@GUARD_PREFIX@_STDDEF_H */