summaryrefslogtreecommitdiff
path: root/gnulib-m4/stddef_h.m4
diff options
context:
space:
mode:
authorJörg Frings-Fürst <debian@jff.email>2022-01-08 11:51:07 +0100
committerJörg Frings-Fürst <debian@jff.email>2022-01-08 11:51:07 +0100
commitbe8efac78d067c138ad8dda03df4336e73f94887 (patch)
tree5f5254a628ba0ef72065b93d949d1c985742ea8e /gnulib-m4/stddef_h.m4
parent7b65dbd4ebade81d504cfe5e681292a58ad1fdf0 (diff)
New upstream version 1.0upstream/1.0
Diffstat (limited to 'gnulib-m4/stddef_h.m4')
-rw-r--r--gnulib-m4/stddef_h.m476
1 files changed, 61 insertions, 15 deletions
diff --git a/gnulib-m4/stddef_h.m4 b/gnulib-m4/stddef_h.m4
index ba3d201..abfd203 100644
--- a/gnulib-m4/stddef_h.m4
+++ b/gnulib-m4/stddef_h.m4
@@ -1,22 +1,54 @@
-dnl A placeholder for <stddef.h>, for platforms that have issues.
-# stddef_h.m4 serial 5
-dnl Copyright (C) 2009-2018 Free Software Foundation, Inc.
+# stddef_h.m4 serial 12
+dnl Copyright (C) 2009-2022 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_DEFUN([gl_STDDEF_H],
+dnl A placeholder for <stddef.h>, for platforms that have issues.
+
+AC_DEFUN_ONCE([gl_STDDEF_H],
[
AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
AC_REQUIRE([gt_TYPE_WCHAR_T])
- STDDEF_H=
- AC_CHECK_TYPE([max_align_t], [], [HAVE_MAX_ALIGN_T=0; STDDEF_H=stddef.h],
- [[#include <stddef.h>
- ]])
+
+ dnl Persuade OpenBSD <stddef.h> to declare max_align_t.
+ AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+ GL_GENERATE_STDDEF_H=false
+
+ dnl Test whether the type max_align_t exists and whether its alignment
+ dnl "is as great as is supported by the implementation in all contexts".
+ AC_CACHE_CHECK([for good max_align_t],
+ [gl_cv_type_max_align_t],
+ [AC_COMPILE_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <stddef.h>
+ unsigned int s = sizeof (max_align_t);
+ #if defined __GNUC__ || defined __clang__ || defined __IBM__ALIGNOF__
+ int check1[2 * (__alignof__ (double) <= __alignof__ (max_align_t)) - 1];
+ int check2[2 * (__alignof__ (long double) <= __alignof__ (max_align_t)) - 1];
+ #endif
+ typedef struct { char a; max_align_t b; } max_helper;
+ typedef struct { char a; long b; } long_helper;
+ typedef struct { char a; double b; } double_helper;
+ typedef struct { char a; long double b; } long_double_helper;
+ int check3[2 * (offsetof (long_helper, b) <= offsetof (max_helper, b)) - 1];
+ int check4[2 * (offsetof (double_helper, b) <= offsetof (max_helper, b)) - 1];
+ int check5[2 * (offsetof (long_double_helper, b) <= offsetof (max_helper, b)) - 1];
+ ]])],
+ [gl_cv_type_max_align_t=yes],
+ [gl_cv_type_max_align_t=no])
+ ])
+ if test $gl_cv_type_max_align_t = no; then
+ HAVE_MAX_ALIGN_T=0
+ GL_GENERATE_STDDEF_H=true
+ fi
+
if test $gt_cv_c_wchar_t = no; then
HAVE_WCHAR_T=0
- STDDEF_H=stddef.h
+ GL_GENERATE_STDDEF_H=true
fi
+
AC_CACHE_CHECK([whether NULL can be used in arbitrary expressions],
[gl_cv_decl_null_works],
[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stddef.h>
@@ -26,22 +58,36 @@ AC_DEFUN([gl_STDDEF_H],
[gl_cv_decl_null_works=no])])
if test $gl_cv_decl_null_works = no; then
REPLACE_NULL=1
- STDDEF_H=stddef.h
+ GL_GENERATE_STDDEF_H=true
fi
- AC_SUBST([STDDEF_H])
- AM_CONDITIONAL([GL_GENERATE_STDDEF_H], [test -n "$STDDEF_H"])
- if test -n "$STDDEF_H"; then
+
+ if $GL_GENERATE_STDDEF_H; then
gl_NEXT_HEADERS([stddef.h])
fi
])
+# gl_STDDEF_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
AC_DEFUN([gl_STDDEF_MODULE_INDICATOR],
[
- dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
- AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
+ dnl Ensure to expand the default settings once only.
+ gl_STDDEF_H_REQUIRE_DEFAULTS
gl_MODULE_INDICATOR_SET_VARIABLE([$1])
])
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd. It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_STDDEF_H_REQUIRE_DEFAULTS],
+[
+ m4_defun(GL_MODULE_INDICATOR_PREFIX[_STDDEF_H_MODULE_INDICATOR_DEFAULTS], [
+ ])
+ m4_require(GL_MODULE_INDICATOR_PREFIX[_STDDEF_H_MODULE_INDICATOR_DEFAULTS])
+ AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
+])
+
AC_DEFUN([gl_STDDEF_H_DEFAULTS],
[
dnl Assume proper GNU behavior unless another module says otherwise.