/* A substitute for POSIX 2008 <stddef.h>, for platforms that have issues.
- Copyright (C) 2009-2014 Free Software Foundation, Inc.
+ Copyright (C) 2009-2016 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
# define wchar_t int
#endif
-/* Some platforms lack max_align_t. */
-#if !@HAVE_MAX_ALIGN_T@
+/* Some platforms lack max_align_t. The check for _GCC_MAX_ALIGN_T is
+ 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)
+/* 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
typedef union
{
- char *__p;
- double __d;
- long double __ld;
- long int __i;
+ 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;
#endif