2 dnl Copyright (C) 2007 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.
7 AC_DEFUN([gl_FUNC_LDEXPL],
9 AC_REQUIRE([gl_MATH_H_DEFAULTS])
11 AC_CACHE_CHECK([whether ldexpl() can be used without linking with libm],
12 [gl_cv_func_ldexpl_no_libm],
14 AC_TRY_LINK([#include <math.h>
16 [return ldexpl (x, -1) > 0;],
17 [gl_cv_func_ldexpl_no_libm=yes],
18 [gl_cv_func_ldexpl_no_libm=no])
20 if test $gl_cv_func_ldexpl_no_libm = no; then
21 AC_CACHE_CHECK([whether ldexpl() can be used with libm],
22 [gl_cv_func_ldexpl_in_libm],
26 AC_TRY_LINK([#include <math.h>
28 [return ldexpl (x, -1) > 0;],
29 [gl_cv_func_ldexpl_in_libm=yes],
30 [gl_cv_func_ldexpl_in_libm=no])
33 if test $gl_cv_func_ldexpl_in_libm = yes; then
37 if test $gl_cv_func_ldexpl_no_libm = yes \
38 || test $gl_cv_func_ldexpl_in_libm = yes; then
40 LIBS="$LIBS $LDEXPL_LIBM"
43 case "$gl_cv_func_ldexpl_works" in
44 *yes) gl_func_ldexpl=yes ;;
45 *) gl_func_ldexpl=no; REPLACE_LDEXPL=1; LDEXPL_LIBM= ;;
50 if test $gl_func_ldexpl = yes; then
51 AC_DEFINE([HAVE_LDEXPL], 1,
52 [Define if the ldexpl() function is available.])
53 dnl Also check whether it's declared.
54 dnl MacOS X 10.3 has ldexpl() in libc but doesn't declare it in <math.h>.
55 AC_CHECK_DECL([ldexpl], , [HAVE_DECL_LDEXPL=0], [#include <math.h>])
62 dnl Test whether ldexpl() works on finite numbers (this fails on AIX 5.1).
63 AC_DEFUN([gl_FUNC_LDEXPL_WORKS],
65 AC_REQUIRE([AC_PROG_CC])
66 AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
67 AC_CACHE_CHECK([whether ldexpl works], [gl_cv_func_ldexpl_works],
71 extern long double ldexpl (long double, int);
74 volatile long double x = 1.0;
75 volatile long double y = ldexpl (x, -1);
77 }], [gl_cv_func_ldexpl_works=yes], [gl_cv_func_ldexpl_works=no],
79 aix*) gl_cv_func_ldexpl_works="guessing no";;
80 *) gl_cv_func_ldexpl_works="guessing yes";;