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comparison m4/size_max.m4 @ 434:b8bf63962a99 3.0

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Added various generated files for release
author lost@l-w.ca
date Fri, 29 Oct 2010 19:20:39 -0600
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433:b142b473f0ee 434:b8bf63962a99
1 # size_max.m4 serial 9
2 dnl Copyright (C) 2003, 2005-2006, 2008-2010 Free Software Foundation, Inc.
3 dnl This file is free software; the Free Software Foundation
4 dnl gives unlimited permission to copy and/or distribute it,
5 dnl with or without modifications, as long as this notice is preserved.
6
7 dnl From Bruno Haible.
8
9 AC_DEFUN([gl_SIZE_MAX],
10 [
11 AC_CHECK_HEADERS([stdint.h])
12 dnl First test whether the system already has SIZE_MAX.
13 AC_CACHE_CHECK([for SIZE_MAX], [gl_cv_size_max], [
14 gl_cv_size_max=
15 AC_EGREP_CPP([Found it], [
16 #include <limits.h>
17 #if HAVE_STDINT_H
18 #include <stdint.h>
19 #endif
20 #ifdef SIZE_MAX
21 Found it
22 #endif
23 ], [gl_cv_size_max=yes])
24 if test -z "$gl_cv_size_max"; then
25 dnl Define it ourselves. Here we assume that the type 'size_t' is not wider
26 dnl than the type 'unsigned long'. Try hard to find a definition that can
27 dnl be used in a preprocessor #if, i.e. doesn't contain a cast.
28 AC_COMPUTE_INT([size_t_bits_minus_1], [sizeof (size_t) * CHAR_BIT - 1],
29 [#include <stddef.h>
30 #include <limits.h>], [size_t_bits_minus_1=])
31 AC_COMPUTE_INT([fits_in_uint], [sizeof (size_t) <= sizeof (unsigned int)],
32 [#include <stddef.h>], [fits_in_uint=])
33 if test -n "$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>
38 extern size_t foo;
39 extern unsigned long foo;
40 ], [], [fits_in_uint=0])
41 fi
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 gl_cv_size_max="(((1U << $size_t_bits_minus_1) - 1) * 2 + 1)"
47 else
48 gl_cv_size_max="(((1UL << $size_t_bits_minus_1) - 1) * 2 + 1)"
49 fi
50 else
51 dnl Shouldn't happen, but who knows...
52 gl_cv_size_max='((size_t)~(size_t)0)'
53 fi
54 fi
55 ])
56 if test "$gl_cv_size_max" != yes; then
57 AC_DEFINE_UNQUOTED([SIZE_MAX], [$gl_cv_size_max],
58 [Define as the maximum value of type 'size_t', if the system doesn't define it.])
59 fi
60 dnl Don't redefine SIZE_MAX in config.h if config.h is re-included after
61 dnl <stdint.h>. Remember that the #undef in AH_VERBATIM gets replaced with
62 dnl #define by AC_DEFINE_UNQUOTED.
63 AH_VERBATIM([SIZE_MAX],
64 [/* Define as the maximum value of type 'size_t', if the system doesn't define
65 it. */
66 #ifndef SIZE_MAX
67 # undef SIZE_MAX
68 #endif])
69 ])
70
71 dnl Autoconf >= 2.61 has AC_COMPUTE_INT built-in.
72 dnl Remove this when we can assume autoconf >= 2.61.
73 m4_ifdef([AC_COMPUTE_INT], [], [
74 AC_DEFUN([AC_COMPUTE_INT], [_AC_COMPUTE_INT([$2],[$1],[$3],[$4])])
75 ])