1# longlong.m4 serial 17
2dnl Copyright (C) 1999-2007, 2009-2012 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7dnl From Paul Eggert.
8
9# Define HAVE_LONG_LONG_INT if 'long long int' works.
10# This fixes a bug in Autoconf 2.61, and can be faster
11# than what's in Autoconf 2.62 through 2.68.
12
13# Note: If the type 'long long int' exists but is only 32 bits large
14# (as on some very old compilers), HAVE_LONG_LONG_INT will not be
15# defined. In this case you can treat 'long long int' like 'long int'.
16
17AC_DEFUN([AC_TYPE_LONG_LONG_INT],
18[
19  AC_REQUIRE([AC_TYPE_UNSIGNED_LONG_LONG_INT])
20  AC_CACHE_CHECK([for long long int], [ac_cv_type_long_long_int],
21     [ac_cv_type_long_long_int=yes
22      if test "x${ac_cv_prog_cc_c99-no}" = xno; then
23        ac_cv_type_long_long_int=$ac_cv_type_unsigned_long_long_int
24        if test $ac_cv_type_long_long_int = yes; then
25          dnl Catch a bug in Tandem NonStop Kernel (OSS) cc -O circa 2004.
26          dnl If cross compiling, assume the bug is not important, since
27          dnl nobody cross compiles for this platform as far as we know.
28          AC_RUN_IFELSE(
29            [AC_LANG_PROGRAM(
30               [[@%:@include <limits.h>
31                 @%:@ifndef LLONG_MAX
32                 @%:@ define HALF \
33                          (1LL << (sizeof (long long int) * CHAR_BIT - 2))
34                 @%:@ define LLONG_MAX (HALF - 1 + HALF)
35                 @%:@endif]],
36               [[long long int n = 1;
37                 int i;
38                 for (i = 0; ; i++)
39                   {
40                     long long int m = n << i;
41                     if (m >> i != n)
42                       return 1;
43                     if (LLONG_MAX / 2 < m)
44                       break;
45                   }
46                 return 0;]])],
47            [],
48            [ac_cv_type_long_long_int=no],
49            [:])
50        fi
51      fi])
52  if test $ac_cv_type_long_long_int = yes; then
53    AC_DEFINE([HAVE_LONG_LONG_INT], [1],
54      [Define to 1 if the system has the type 'long long int'.])
55  fi
56])
57
58# Define HAVE_UNSIGNED_LONG_LONG_INT if 'unsigned long long int' works.
59# This fixes a bug in Autoconf 2.61, and can be faster
60# than what's in Autoconf 2.62 through 2.68.
61
62# Note: If the type 'unsigned long long int' exists but is only 32 bits
63# large (as on some very old compilers), AC_TYPE_UNSIGNED_LONG_LONG_INT
64# will not be defined. In this case you can treat 'unsigned long long int'
65# like 'unsigned long int'.
66
67AC_DEFUN([AC_TYPE_UNSIGNED_LONG_LONG_INT],
68[
69  AC_CACHE_CHECK([for unsigned long long int],
70    [ac_cv_type_unsigned_long_long_int],
71    [ac_cv_type_unsigned_long_long_int=yes
72     if test "x${ac_cv_prog_cc_c99-no}" = xno; then
73       AC_LINK_IFELSE(
74         [_AC_TYPE_LONG_LONG_SNIPPET],
75         [],
76         [ac_cv_type_unsigned_long_long_int=no])
77     fi])
78  if test $ac_cv_type_unsigned_long_long_int = yes; then
79    AC_DEFINE([HAVE_UNSIGNED_LONG_LONG_INT], [1],
80      [Define to 1 if the system has the type 'unsigned long long int'.])
81  fi
82])
83
84# Expands to a C program that can be used to test for simultaneous support
85# of 'long long' and 'unsigned long long'. We don't want to say that
86# 'long long' is available if 'unsigned long long' is not, or vice versa,
87# because too many programs rely on the symmetry between signed and unsigned
88# integer types (excluding 'bool').
89AC_DEFUN([_AC_TYPE_LONG_LONG_SNIPPET],
90[
91  AC_LANG_PROGRAM(
92    [[/* For now, do not test the preprocessor; as of 2007 there are too many
93         implementations with broken preprocessors.  Perhaps this can
94         be revisited in 2012.  In the meantime, code should not expect
95         #if to work with literals wider than 32 bits.  */
96      /* Test literals.  */
97      long long int ll = 9223372036854775807ll;
98      long long int nll = -9223372036854775807LL;
99      unsigned long long int ull = 18446744073709551615ULL;
100      /* Test constant expressions.   */
101      typedef int a[((-9223372036854775807LL < 0 && 0 < 9223372036854775807ll)
102                     ? 1 : -1)];
103      typedef int b[(18446744073709551615ULL <= (unsigned long long int) -1
104                     ? 1 : -1)];
105      int i = 63;]],
106    [[/* Test availability of runtime routines for shift and division.  */
107      long long int llmax = 9223372036854775807ll;
108      unsigned long long int ullmax = 18446744073709551615ull;
109      return ((ll << 63) | (ll >> 63) | (ll < i) | (ll > i)
110              | (llmax / ll) | (llmax % ll)
111              | (ull << 63) | (ull >> 63) | (ull << i) | (ull >> i)
112              | (ullmax / ull) | (ullmax % ull));]])
113])
114