2 dnl Copyright (C) 2010-2012 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_EXPL],
9 AC_REQUIRE([gl_MATH_H_DEFAULTS])
10 AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
12 dnl Persuade glibc <math.h> to declare expl().
13 AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
16 AC_CACHE_CHECK([whether expl() can be used without linking with libm],
17 [gl_cv_func_expl_no_libm],
21 [[#ifndef __NO_MATH_INLINES
22 # define __NO_MATH_INLINES 1 /* for glibc */
26 [[return expl (x) > 1.5;]])],
27 [gl_cv_func_expl_no_libm=yes],
28 [gl_cv_func_expl_no_libm=no])
30 if test $gl_cv_func_expl_no_libm = no; then
31 AC_CACHE_CHECK([whether expl() can be used with libm],
32 [gl_cv_func_expl_in_libm],
38 [[#ifndef __NO_MATH_INLINES
39 # define __NO_MATH_INLINES 1 /* for glibc */
43 [[return expl (x) > 1.5;]])],
44 [gl_cv_func_expl_in_libm=yes],
45 [gl_cv_func_expl_in_libm=no])
48 if test $gl_cv_func_expl_in_libm = yes; then
52 if test $gl_cv_func_expl_no_libm = yes \
53 || test $gl_cv_func_expl_in_libm = yes; then
54 dnl Also check whether it's declared.
55 dnl MacOS X 10.3 has expl() in libc but doesn't declare it in <math.h>.
56 AC_CHECK_DECL([expl], , [HAVE_DECL_EXPL=0], [[#include <math.h>]])
60 dnl Find libraries needed to link lib/expl.c.
61 if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
62 AC_REQUIRE([gl_FUNC_EXP])
65 AC_REQUIRE([gl_FUNC_FLOORL])
66 EXPL_LIBM="$FLOORL_LIBM"