diff options
Diffstat (limited to 'm4/size_max.m4')
-rw-r--r-- | m4/size_max.m4 | 81 |
1 files changed, 40 insertions, 41 deletions
diff --git a/m4/size_max.m4 b/m4/size_max.m4 index bfba811e..5762fc33 100644 --- a/m4/size_max.m4 +++ b/m4/size_max.m4 | |||
@@ -1,8 +1,10 @@ | |||
1 | # size_max.m4 serial 5 | 1 | # size_max.m4 serial 2 |
2 | dnl Copyright (C) 2003, 2005-2006 Free Software Foundation, Inc. | 2 | dnl Copyright (C) 2003 Free Software Foundation, Inc. |
3 | dnl This file is free software; the Free Software Foundation | 3 | dnl This file is free software, distributed under the terms of the GNU |
4 | dnl gives unlimited permission to copy and/or distribute it, | 4 | dnl General Public License. As a special exception to the GNU General |
5 | dnl with or without modifications, as long as this notice is preserved. | 5 | dnl Public License, this file may be distributed as part of a program |
6 | dnl that contains a configuration script generated by Autoconf, under | ||
7 | dnl the same distribution terms as the rest of that program. | ||
6 | 8 | ||
7 | dnl From Bruno Haible. | 9 | dnl From Bruno Haible. |
8 | 10 | ||
@@ -11,9 +13,8 @@ AC_DEFUN([gl_SIZE_MAX], | |||
11 | AC_CHECK_HEADERS(stdint.h) | 13 | AC_CHECK_HEADERS(stdint.h) |
12 | dnl First test whether the system already has SIZE_MAX. | 14 | dnl First test whether the system already has SIZE_MAX. |
13 | AC_MSG_CHECKING([for SIZE_MAX]) | 15 | AC_MSG_CHECKING([for SIZE_MAX]) |
14 | AC_CACHE_VAL([gl_cv_size_max], [ | 16 | result= |
15 | gl_cv_size_max= | 17 | AC_EGREP_CPP([Found it], [ |
16 | AC_EGREP_CPP([Found it], [ | ||
17 | #include <limits.h> | 18 | #include <limits.h> |
18 | #if HAVE_STDINT_H | 19 | #if HAVE_STDINT_H |
19 | #include <stdint.h> | 20 | #include <stdint.h> |
@@ -21,42 +22,40 @@ AC_DEFUN([gl_SIZE_MAX], | |||
21 | #ifdef SIZE_MAX | 22 | #ifdef SIZE_MAX |
22 | Found it | 23 | Found it |
23 | #endif | 24 | #endif |
24 | ], gl_cv_size_max=yes) | 25 | ], result=yes) |
25 | if test -z "$gl_cv_size_max"; then | 26 | if test -z "$result"; then |
26 | dnl Define it ourselves. Here we assume that the type 'size_t' is not wider | 27 | 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 than the type 'unsigned long'. |
28 | dnl be used in a preprocessor #if, i.e. doesn't contain a cast. | 29 | dnl The _AC_COMPUTE_INT macro works up to LONG_MAX, since it uses 'expr', |
29 | _AC_COMPUTE_INT([sizeof (size_t) * CHAR_BIT - 1], size_t_bits_minus_1, | 30 | dnl which is guaranteed to work from LONG_MIN to LONG_MAX. |
30 | [#include <stddef.h> | 31 | _AC_COMPUTE_INT([~(size_t)0 / 10], res_hi, |
31 | #include <limits.h>], size_t_bits_minus_1=) | 32 | [#include <stddef.h>], result=?) |
32 | _AC_COMPUTE_INT([sizeof (size_t) <= sizeof (unsigned int)], fits_in_uint, | 33 | _AC_COMPUTE_INT([~(size_t)0 % 10], res_lo, |
33 | [#include <stddef.h>], fits_in_uint=) | 34 | [#include <stddef.h>], result=?) |
34 | if test -n "$size_t_bits_minus_1" && test -n "$fits_in_uint"; then | 35 | _AC_COMPUTE_INT([sizeof (size_t) <= sizeof (unsigned int)], fits_in_uint, |
35 | if test $fits_in_uint = 1; then | 36 | [#include <stddef.h>], result=?) |
36 | dnl Even though SIZE_MAX fits in an unsigned int, it must be of type | 37 | if test "$fits_in_uint" = 1; then |
37 | dnl 'unsigned long' if the type 'size_t' is the same as 'unsigned long'. | 38 | dnl Even though SIZE_MAX fits in an unsigned int, it must be of type |
38 | AC_TRY_COMPILE([#include <stddef.h> | 39 | dnl 'unsigned long' if the type 'size_t' is the same as 'unsigned long'. |
39 | extern size_t foo; | 40 | AC_TRY_COMPILE([#include <stddef.h> |
40 | extern unsigned long foo; | 41 | extern size_t foo; |
41 | ], [], fits_in_uint=0) | 42 | extern unsigned long foo; |
42 | fi | 43 | ], [], fits_in_uint=0) |
43 | dnl We cannot use 'expr' to simplify this expression, because 'expr' | 44 | fi |
44 | dnl works only with 'long' integers in the host environment, while we | 45 | if test -z "$result"; then |
45 | dnl might be cross-compiling from a 32-bit platform to a 64-bit platform. | 46 | if test "$fits_in_uint" = 1; then |
46 | if test $fits_in_uint = 1; then | 47 | result="$res_hi$res_lo"U |
47 | gl_cv_size_max="(((1U << $size_t_bits_minus_1) - 1) * 2 + 1)" | ||
48 | else | ||
49 | gl_cv_size_max="(((1UL << $size_t_bits_minus_1) - 1) * 2 + 1)" | ||
50 | fi | ||
51 | else | 48 | else |
52 | dnl Shouldn't happen, but who knows... | 49 | result="$res_hi$res_lo"UL |
53 | gl_cv_size_max='((size_t)~(size_t)0)' | ||
54 | fi | 50 | fi |
51 | else | ||
52 | dnl Shouldn't happen, but who knows... | ||
53 | result='~(size_t)0' | ||
55 | fi | 54 | fi |
56 | ]) | 55 | fi |
57 | AC_MSG_RESULT([$gl_cv_size_max]) | 56 | AC_MSG_RESULT([$result]) |
58 | if test "$gl_cv_size_max" != yes; then | 57 | if test "$result" != yes; then |
59 | AC_DEFINE_UNQUOTED([SIZE_MAX], [$gl_cv_size_max], | 58 | AC_DEFINE_UNQUOTED([SIZE_MAX], [$result], |
60 | [Define as the maximum value of type 'size_t', if the system doesn't define it.]) | 59 | [Define as the maximum value of type 'size_t', if the system doesn't define it.]) |
61 | fi | 60 | fi |
62 | ]) | 61 | ]) |