60 lines
1.9 KiB
Text
60 lines
1.9 KiB
Text
|
# size_max.m4 serial 2
|
||
|
|
dnl Copyright (C) 2003 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.
|
||
|
|
|
||
|
|
dnl From Bruno Haible.
|
||
|
|
|
||
|
|
AC_DEFUN([gl_SIZE_MAX],
|
||
|
|
[
|
||
|
|
AC_CHECK_HEADERS(stdint.h)
|
||
|
|
dnl First test whether the system already has SIZE_MAX.
|
||
|
|
AC_MSG_CHECKING([for SIZE_MAX])
|
||
|
|
result=
|
||
|
|
AC_EGREP_CPP([Found it], [
|
||
|
|
#include <limits.h>
|
||
|
|
#if HAVE_STDINT_H
|
||
|
|
#include <stdint.h>
|
||
|
|
#endif
|
||
|
|
#ifdef SIZE_MAX
|
||
|
|
Found it
|
||
|
|
#endif
|
||
|
|
], 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
|
||
|
|
result="$res_hi$res_lo"UL
|
||
|
|
fi
|
||
|
|
else
|
||
|
|
dnl Shouldn't happen, but who knows...
|
||
|
|
result='~(size_t)0'
|
||
|
|
fi
|
||
|
|
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
|
||
|
|
])
|