-# Check for stdalign.h that conforms to C1x.
+# Check for stdalign.h that conforms to C11.
-dnl Copyright 2011-2012 Free Software Foundation, Inc.
+dnl Copyright 2011-2013 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
[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 52023
+ <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52023>. */
+ #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 test_double[ao (double) % _Alignof (double) == 0 ? 1 : -1];
+ char test_long[ao (long int) % _Alignof (long int) == 0 ? 1 : -1];
+ char test_alignof[alignof (double) == _Alignof (double) ? 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;
+ 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],