coreutils/m4/ullong_max.m4
2005-01-22 06:25:53 +00:00

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# ullong_max.m4 - define ULLONG_MAX if necessary
dnl Copyright (C) 2005 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
# Written by Paul Eggert.
AC_DEFUN([gl_ULLONG_MAX],
[
dnl Avoid _AC_COMPUTE_INT-related macros, as they may not work with
dnl types wider than long int, due to problems with expr.
AC_CACHE_CHECK([for ULLONG_MAX], gl_cv_ullong_max,
[gl_cv_ullong_max=no
AC_EGREP_CPP([ULLONG_MAX is defined],
[
#include <limits.h>
#ifdef ULLONG_MAX
"ULLONG_MAX is defined"
#endif
],
[gl_cv_ullong_max=yes])
case $gl_cv_ullong_max in
no)
for gl_expr in \
18446744073709551615ULL \
4722366482869645213695ULL \
340282366920938463463374607431768211455ULL
do
AC_TRY_COMPILE([],
[char test[$gl_expr == (unsigned long long int) -1 ? 1 : -1];
static unsigned long long int i = $gl_expr;
return i && test;],
[gl_cv_ullong_max=$gl_expr])
test $gl_cv_ullong_max != no && break
done
esac])
case $gl_cv_ullong_max in
yes | no) ;;
*)
AC_DEFINE_UNQUOTED([ULLONG_MAX], [$gl_cv_ullong_max],
[Define as the maximum value of the type 'unsigned long long int',
if the system doesn't define it, and if the system has that type.]);;
esac
])