1# longlong.m4 serial 14
2dnl Copyright (C) 1999-2007, 2009 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, but can be removed once we
11# assume 2.62 everywhere.
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_CACHE_CHECK([for long long int], [ac_cv_type_long_long_int],
20    [AC_LINK_IFELSE(
21       [_AC_TYPE_LONG_LONG_SNIPPET],
22       [dnl This catches a bug in Tandem NonStop Kernel (OSS) cc -O circa 2004.
23	dnl If cross compiling, assume the bug isn't important, since
24	dnl nobody cross compiles for this platform as far as we know.
25	AC_RUN_IFELSE(
26	  [AC_LANG_PROGRAM(
27	     [[@%:@include <limits.h>
28	       @%:@ifndef LLONG_MAX
29	       @%:@ define HALF \
30			(1LL << (sizeof (long long int) * CHAR_BIT - 2))
31	       @%:@ define LLONG_MAX (HALF - 1 + HALF)
32	       @%:@endif]],
33	     [[long long int n = 1;
34	       int i;
35	       for (i = 0; ; i++)
36		 {
37		   long long int m = n << i;
38		   if (m >> i != n)
39		     return 1;
40		   if (LLONG_MAX / 2 < m)
41		     break;
42		 }
43	       return 0;]])],
44	  [ac_cv_type_long_long_int=yes],
45	  [ac_cv_type_long_long_int=no],
46	  [ac_cv_type_long_long_int=yes])],
47       [ac_cv_type_long_long_int=no])])
48  if test $ac_cv_type_long_long_int = yes; then
49    AC_DEFINE([HAVE_LONG_LONG_INT], [1],
50      [Define to 1 if the system has the type `long long int'.])
51  fi
52])
53
54# Define HAVE_UNSIGNED_LONG_LONG_INT if 'unsigned long long int' works.
55# This fixes a bug in Autoconf 2.61, but can be removed once we
56# assume 2.62 everywhere.
57
58# Note: If the type 'unsigned long long int' exists but is only 32 bits
59# large (as on some very old compilers), AC_TYPE_UNSIGNED_LONG_LONG_INT
60# will not be defined. In this case you can treat 'unsigned long long int'
61# like 'unsigned long int'.
62
63AC_DEFUN([AC_TYPE_UNSIGNED_LONG_LONG_INT],
64[
65  AC_CACHE_CHECK([for unsigned long long int],
66    [ac_cv_type_unsigned_long_long_int],
67    [AC_LINK_IFELSE(
68       [_AC_TYPE_LONG_LONG_SNIPPET],
69       [ac_cv_type_unsigned_long_long_int=yes],
70       [ac_cv_type_unsigned_long_long_int=no])])
71  if test $ac_cv_type_unsigned_long_long_int = yes; then
72    AC_DEFINE([HAVE_UNSIGNED_LONG_LONG_INT], [1],
73      [Define to 1 if the system has the type `unsigned long long int'.])
74  fi
75])
76
77# Expands to a C program that can be used to test for simultaneous support
78# of 'long long' and 'unsigned long long'. We don't want to say that
79# 'long long' is available if 'unsigned long long' is not, or vice versa,
80# because too many programs rely on the symmetry between signed and unsigned
81# integer types (excluding 'bool').
82AC_DEFUN([_AC_TYPE_LONG_LONG_SNIPPET],
83[
84  AC_LANG_PROGRAM(
85    [[/* For now, do not test the preprocessor; as of 2007 there are too many
86	 implementations with broken preprocessors.  Perhaps this can
87	 be revisited in 2012.  In the meantime, code should not expect
88	 #if to work with literals wider than 32 bits.  */
89      /* Test literals.  */
90      long long int ll = 9223372036854775807ll;
91      long long int nll = -9223372036854775807LL;
92      unsigned long long int ull = 18446744073709551615ULL;
93      /* Test constant expressions.   */
94      typedef int a[((-9223372036854775807LL < 0 && 0 < 9223372036854775807ll)
95		     ? 1 : -1)];
96      typedef int b[(18446744073709551615ULL <= (unsigned long long int) -1
97		     ? 1 : -1)];
98      int i = 63;]],
99    [[/* Test availability of runtime routines for shift and division.  */
100      long long int llmax = 9223372036854775807ll;
101      unsigned long long int ullmax = 18446744073709551615ull;
102      return ((ll << 63) | (ll >> 63) | (ll < i) | (ll > i)
103	      | (llmax / ll) | (llmax % ll)
104	      | (ull << 63) | (ull >> 63) | (ull << i) | (ull >> i)
105	      | (ullmax / ull) | (ullmax % ull));]])
106])
107