24
if test -z "$result"; then
25
dnl Define it ourselves. Here we assume that the type 'size_t' is not wider
26
dnl than the type 'unsigned long'. Try hard to find a definition that can
27
dnl be used in a preprocessor #if, i.e. doesn't contain a cast.
28
_AC_COMPUTE_INT([sizeof (size_t) * CHAR_BIT - 1], size_t_bits_minus_1,
24
], gl_cv_size_max=yes)
25
if test -z "$gl_cv_size_max"; then
26
dnl Define it ourselves. Here we assume that the type 'size_t' is not wider
27
dnl than the type 'unsigned long'. Try hard to find a definition that can
28
dnl be used in a preprocessor #if, i.e. doesn't contain a cast.
29
_AC_COMPUTE_INT([sizeof (size_t) * CHAR_BIT - 1], size_t_bits_minus_1,
30
31
#include <limits.h>], size_t_bits_minus_1=)
31
_AC_COMPUTE_INT([sizeof (size_t) <= sizeof (unsigned int)], fits_in_uint,
32
[#include <stddef.h>], fits_in_uint=)
33
if test -n "$size_t_bits_minus_1" && test -n "$fits_in_uint"; then
34
if test $fits_in_uint = 1; then
35
dnl Even though SIZE_MAX fits in an unsigned int, it must be of type
36
dnl 'unsigned long' if the type 'size_t' is the same as 'unsigned long'.
37
AC_TRY_COMPILE([#include <stddef.h>
39
extern unsigned long foo;
40
], [], fits_in_uint=0)
42
dnl We cannot use 'expr' to simplify this expression, because 'expr'
43
dnl works only with 'long' integers in the host environment, while we
44
dnl might be cross-compiling from a 32-bit platform to a 64-bit platform.
45
if test $fits_in_uint = 1; then
46
result="(((1U << $size_t_bits_minus_1) - 1) * 2 + 1)"
32
_AC_COMPUTE_INT([sizeof (size_t) <= sizeof (unsigned int)], fits_in_uint,
33
[#include <stddef.h>], fits_in_uint=)
34
if test -n "$size_t_bits_minus_1" && test -n "$fits_in_uint"; then
35
if test $fits_in_uint = 1; then
36
dnl Even though SIZE_MAX fits in an unsigned int, it must be of type
37
dnl 'unsigned long' if the type 'size_t' is the same as 'unsigned long'.
38
AC_TRY_COMPILE([#include <stddef.h>
40
extern unsigned long foo;
41
], [], fits_in_uint=0)
43
dnl We cannot use 'expr' to simplify this expression, because 'expr'
44
dnl works only with 'long' integers in the host environment, while we
45
dnl might be cross-compiling from a 32-bit platform to a 64-bit platform.
46
if test $fits_in_uint = 1; then
47
gl_cv_size_max="(((1U << $size_t_bits_minus_1) - 1) * 2 + 1)"
49
gl_cv_size_max="(((1UL << $size_t_bits_minus_1) - 1) * 2 + 1)"
48
result="(((1UL << $size_t_bits_minus_1) - 1) * 2 + 1)"
52
dnl Shouldn't happen, but who knows...
53
gl_cv_size_max='((size_t)~(size_t)0)'
51
dnl Shouldn't happen, but who knows...
52
result='((size_t)~(size_t)0)'
55
AC_MSG_RESULT([$result])
56
if test "$result" != yes; then
57
AC_DEFINE_UNQUOTED([SIZE_MAX], [$result],
57
AC_MSG_RESULT([$gl_cv_size_max])
58
if test "$gl_cv_size_max" != yes; then
59
AC_DEFINE_UNQUOTED([SIZE_MAX], [$gl_cv_size_max],
58
60
[Define as the maximum value of type 'size_t', if the system doesn't define it.])