-# size_max.m4 serial 6
-dnl Copyright (C) 2003, 2005-2006 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.
+# size_max.m4 serial 2
+dnl Copyright (C) 2003 Free Software Foundation, Inc.
+dnl This file is free software, distributed under the terms of the GNU
+dnl General Public License. As a special exception to the GNU General
+dnl Public License, this file may be distributed as part of a program
+dnl that contains a configuration script generated by Autoconf, under
+dnl the same distribution terms as the rest of that program.
dnl From Bruno Haible.
AC_CHECK_HEADERS(stdint.h)
dnl First test whether the system already has SIZE_MAX.
AC_MSG_CHECKING([for SIZE_MAX])
- AC_CACHE_VAL([gl_cv_size_max], [
- gl_cv_size_max=
- AC_EGREP_CPP([Found it], [
+ result=
+ AC_EGREP_CPP([Found it], [
#include <limits.h>
#if HAVE_STDINT_H
#include <stdint.h>
#ifdef SIZE_MAX
Found it
#endif
-], gl_cv_size_max=yes)
- if test -z "$gl_cv_size_max"; then
- dnl Define it ourselves. Here we assume that the type 'size_t' is not wider
- dnl than the type 'unsigned long'. Try hard to find a definition that can
- dnl be used in a preprocessor #if, i.e. doesn't contain a cast.
- AC_COMPUTE_INT([size_t_bits_minus_1], [sizeof (size_t) * CHAR_BIT - 1],
- [#include <stddef.h>
-#include <limits.h>], size_t_bits_minus_1=)
- AC_COMPUTE_INT([fits_in_uint], [sizeof (size_t) <= sizeof (unsigned int)],
- [#include <stddef.h>], fits_in_uint=)
- if test -n "$size_t_bits_minus_1" && test -n "$fits_in_uint"; then
- if test $fits_in_uint = 1; then
- dnl Even though SIZE_MAX fits in an unsigned int, it must be of type
- dnl 'unsigned long' if the type 'size_t' is the same as 'unsigned long'.
- AC_TRY_COMPILE([#include <stddef.h>
- extern size_t foo;
- extern unsigned long foo;
- ], [], fits_in_uint=0)
- fi
- dnl We cannot use 'expr' to simplify this expression, because 'expr'
- dnl works only with 'long' integers in the host environment, while we
- dnl might be cross-compiling from a 32-bit platform to a 64-bit platform.
- if test $fits_in_uint = 1; then
- gl_cv_size_max="(((1U << $size_t_bits_minus_1) - 1) * 2 + 1)"
- else
- gl_cv_size_max="(((1UL << $size_t_bits_minus_1) - 1) * 2 + 1)"
- fi
+], result=yes)
+ if test -z "$result"; then
+ dnl Define it ourselves. Here we assume that the type 'size_t' is not wider
+ dnl than the type 'unsigned long'.
+ dnl The _AC_COMPUTE_INT macro works up to LONG_MAX, since it uses 'expr',
+ dnl which is guaranteed to work from LONG_MIN to LONG_MAX.
+ _AC_COMPUTE_INT([~(size_t)0 / 10], res_hi,
+ [#include <stddef.h>], result=?)
+ _AC_COMPUTE_INT([~(size_t)0 % 10], res_lo,
+ [#include <stddef.h>], result=?)
+ _AC_COMPUTE_INT([sizeof (size_t) <= sizeof (unsigned int)], fits_in_uint,
+ [#include <stddef.h>], result=?)
+ if test "$fits_in_uint" = 1; then
+ dnl Even though SIZE_MAX fits in an unsigned int, it must be of type
+ dnl 'unsigned long' if the type 'size_t' is the same as 'unsigned long'.
+ AC_TRY_COMPILE([#include <stddef.h>
+ extern size_t foo;
+ extern unsigned long foo;
+ ], [], fits_in_uint=0)
+ fi
+ if test -z "$result"; then
+ if test "$fits_in_uint" = 1; then
+ result="$res_hi$res_lo"U
else
- dnl Shouldn't happen, but who knows...
- gl_cv_size_max='((size_t)~(size_t)0)'
+ result="$res_hi$res_lo"UL
fi
+ else
+ dnl Shouldn't happen, but who knows...
+ result='~(size_t)0'
fi
- ])
- AC_MSG_RESULT([$gl_cv_size_max])
- if test "$gl_cv_size_max" != yes; then
- AC_DEFINE_UNQUOTED([SIZE_MAX], [$gl_cv_size_max],
+ fi
+ AC_MSG_RESULT([$result])
+ if test "$result" != yes; then
+ AC_DEFINE_UNQUOTED([SIZE_MAX], [$result],
[Define as the maximum value of type 'size_t', if the system doesn't define it.])
fi
])
-
-dnl Autoconf >= 2.61 has AC_COMPUTE_INT built-in.
-dnl Remove this when we can assume autoconf >= 2.61.
-m4_ifdef([AC_COMPUTE_INT], [], [
- AC_DEFUN([AC_COMPUTE_INT], [_AC_COMPUTE_INT([$2],[$1],[$3],[$4])])
-])