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# ldexpl.m4 serial 4
dnl Copyright (C) 2007-2010 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.
AC_DEFUN([gl_FUNC_LDEXPL],
[
AC_REQUIRE([gl_MATH_H_DEFAULTS])
LDEXPL_LIBM=
AC_CACHE_CHECK([whether ldexpl() can be used without linking with libm],
[gl_cv_func_ldexpl_no_libm],
[
AC_TRY_LINK([#include <math.h>
long double x;],
[return ldexpl (x, -1) > 0;],
[gl_cv_func_ldexpl_no_libm=yes],
[gl_cv_func_ldexpl_no_libm=no])
])
if test $gl_cv_func_ldexpl_no_libm = no; then
AC_CACHE_CHECK([whether ldexpl() can be used with libm],
[gl_cv_func_ldexpl_in_libm],
[
save_LIBS="$LIBS"
LIBS="$LIBS -lm"
AC_TRY_LINK([#include <math.h>
long double x;],
[return ldexpl (x, -1) > 0;],
[gl_cv_func_ldexpl_in_libm=yes],
[gl_cv_func_ldexpl_in_libm=no])
LIBS="$save_LIBS"
])
if test $gl_cv_func_ldexpl_in_libm = yes; then
LDEXPL_LIBM=-lm
fi
fi
if test $gl_cv_func_ldexpl_no_libm = yes \
|| test $gl_cv_func_ldexpl_in_libm = yes; then
save_LIBS="$LIBS"
LIBS="$LIBS $LDEXPL_LIBM"
gl_FUNC_LDEXPL_WORKS
LIBS="$save_LIBS"
case "$gl_cv_func_ldexpl_works" in
*yes) gl_func_ldexpl=yes ;;
*) gl_func_ldexpl=no; REPLACE_LDEXPL=1; LDEXPL_LIBM= ;;
esac
else
gl_func_ldexpl=no
fi
if test $gl_func_ldexpl = yes; then
AC_DEFINE([HAVE_LDEXPL], [1],
[Define if the ldexpl() function is available.])
dnl Also check whether it's declared.
dnl MacOS X 10.3 has ldexpl() in libc but doesn't declare it in <math.h>.
AC_CHECK_DECL([ldexpl], , [HAVE_DECL_LDEXPL=0], [#include <math.h>])
else
HAVE_DECL_LDEXPL=0
AC_LIBOBJ([ldexpl])
fi
AC_SUBST([LDEXPL_LIBM])
])
dnl Test whether ldexpl() works on finite numbers (this fails on AIX 5.1
dnl and MacOS X 10.4/PowerPC).
AC_DEFUN([gl_FUNC_LDEXPL_WORKS],
[
AC_REQUIRE([AC_PROG_CC])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CACHE_CHECK([whether ldexpl works], [gl_cv_func_ldexpl_works],
[
AC_TRY_RUN([
#include <math.h>
extern long double ldexpl (long double, int);
int main()
{
volatile long double x1 = 1.0;
volatile long double y1 = ldexpl (x1, -1);
volatile long double x2 = 1.73205L;
volatile long double y2 = ldexpl (x2, 0);
return (y1 != 0.5L) || (y2 != x2);
}], [gl_cv_func_ldexpl_works=yes], [gl_cv_func_ldexpl_works=no],
[case "$host_os" in
aix*) gl_cv_func_ldexpl_works="guessing no";;
*) gl_cv_func_ldexpl_works="guessing yes";;
esac
])
])
])
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