Contents 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 | # 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 | ]) |