2 dnl Copyright (C) 2010-2011 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_ATANL],
9 AC_REQUIRE([gl_MATH_H_DEFAULTS])
10 AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
12 dnl Persuade glibc <math.h> to declare atanl().
13 AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
16 AC_CACHE_CHECK([whether atanl() can be used without linking with libm],
17 [gl_cv_func_atanl_no_libm],
21 [[#ifndef __NO_MATH_INLINES
22 # define __NO_MATH_INLINES 1 /* for glibc */
26 [[return atanl (x) > 1;]])],
27 [gl_cv_func_atanl_no_libm=yes],
28 [gl_cv_func_atanl_no_libm=no])
30 if test $gl_cv_func_atanl_no_libm = no; then
31 AC_CACHE_CHECK([whether atanl() can be used with libm],
32 [gl_cv_func_atanl_in_libm],
38 [[#ifndef __NO_MATH_INLINES
39 # define __NO_MATH_INLINES 1 /* for glibc */
43 [[return atanl (x) > 1;]])],
44 [gl_cv_func_atanl_in_libm=yes],
45 [gl_cv_func_atanl_in_libm=no])
48 if test $gl_cv_func_atanl_in_libm = yes; then
52 if test $gl_cv_func_atanl_no_libm = yes \
53 || test $gl_cv_func_atanl_in_libm = yes; then
54 dnl Also check whether it's declared.
55 dnl MacOS X 10.3 has atanl() in libc but doesn't declare it in <math.h>.
56 AC_CHECK_DECL([atanl], , [HAVE_DECL_ATANL=0], [[#include <math.h>]])
60 dnl Find libraries needed to link lib/atanl.c.
61 if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
62 AC_REQUIRE([gl_FUNC_ATAN])
63 ATANL_LIBM="$ATAN_LIBM"
65 AC_REQUIRE([gl_FUNC_ISNANL])
66 dnl Append $ISNANL_LIBM to ATANL_LIBM, avoiding gratuitous duplicates.
67 case " $ATANL_LIBM " in
68 *" $ISNANL_LIBM "*) ;;
69 *) ATANL_LIBM="$ATANL_LIBM $ISNANL_LIBM" ;;
73 AC_SUBST([ATANL_LIBM])