Annotation of /trunk/xmms/gentoo-m4/size_max.m4
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Tue May 8 20:52:56 2007 UTC (17 years, 4 months ago) by niro
File size: 2106 byte(s)
Tue May 8 20:52:56 2007 UTC (17 years, 4 months ago) by niro
File size: 2106 byte(s)
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1 | niro | 153 | # size_max.m4 serial 2 |
2 | dnl Copyright (C) 2003 Free Software Foundation, Inc. | ||
3 | dnl This file is free software, distributed under the terms of the GNU | ||
4 | dnl General Public License. As a special exception to the GNU General | ||
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. | ||
8 | |||
9 | dnl From Bruno Haible. | ||
10 | |||
11 | AC_DEFUN([gl_SIZE_MAX], | ||
12 | [ | ||
13 | AC_CHECK_HEADERS(stdint.h) | ||
14 | dnl First test whether the system already has SIZE_MAX. | ||
15 | AC_MSG_CHECKING([for SIZE_MAX]) | ||
16 | result= | ||
17 | AC_EGREP_CPP([Found it], [ | ||
18 | #include <limits.h> | ||
19 | #if HAVE_STDINT_H | ||
20 | #include <stdint.h> | ||
21 | #endif | ||
22 | #ifdef SIZE_MAX | ||
23 | Found it | ||
24 | #endif | ||
25 | ], result=yes) | ||
26 | if test -z "$result"; then | ||
27 | dnl Define it ourselves. Here we assume that the type 'size_t' is not wider | ||
28 | dnl than the type 'unsigned long'. | ||
29 | dnl The _AC_COMPUTE_INT macro works up to LONG_MAX, since it uses 'expr', | ||
30 | dnl which is guaranteed to work from LONG_MIN to LONG_MAX. | ||
31 | _AC_COMPUTE_INT([~(size_t)0 / 10], res_hi, | ||
32 | [#include <stddef.h>], result=?) | ||
33 | _AC_COMPUTE_INT([~(size_t)0 % 10], res_lo, | ||
34 | [#include <stddef.h>], result=?) | ||
35 | _AC_COMPUTE_INT([sizeof (size_t) <= sizeof (unsigned int)], fits_in_uint, | ||
36 | [#include <stddef.h>], result=?) | ||
37 | if test "$fits_in_uint" = 1; then | ||
38 | dnl Even though SIZE_MAX fits in an unsigned int, it must be of type | ||
39 | dnl 'unsigned long' if the type 'size_t' is the same as 'unsigned long'. | ||
40 | AC_TRY_COMPILE([#include <stddef.h> | ||
41 | extern size_t foo; | ||
42 | extern unsigned long foo; | ||
43 | ], [], fits_in_uint=0) | ||
44 | fi | ||
45 | if test -z "$result"; then | ||
46 | if test "$fits_in_uint" = 1; then | ||
47 | result="$res_hi$res_lo"U | ||
48 | else | ||
49 | result="$res_hi$res_lo"UL | ||
50 | fi | ||
51 | else | ||
52 | dnl Shouldn't happen, but who knows... | ||
53 | result='~(size_t)0' | ||
54 | fi | ||
55 | fi | ||
56 | AC_MSG_RESULT([$result]) | ||
57 | if test "$result" != yes; then | ||
58 | AC_DEFINE_UNQUOTED([SIZE_MAX], [$result], | ||
59 | [Define as the maximum value of type 'size_t', if the system doesn't define it.]) | ||
60 | fi | ||
61 | ]) |