3 dnl Copyright (C) 2011-2024 Free Software Foundation, Inc.
4 dnl This file is free software; the Free Software Foundation
5 dnl gives unlimited permission to copy and/or distribute it,
6 dnl with or without modifications, as long as this notice is preserved.
8 AC_DEFUN([gl_FUNC_ATANF],
10 AC_REQUIRE([gl_MATH_H_DEFAULTS])
11 AC_REQUIRE([gl_FUNC_ATAN])
13 dnl Persuade glibc <math.h> to declare atanf().
14 AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
16 dnl Test whether atanf() exists. Assume that atanf(), if it exists, is
17 dnl defined in the same library as atan().
19 LIBS="$LIBS $ATAN_LIBM"
20 AC_CHECK_FUNCS([atanf])
22 if test $ac_cv_func_atanf = yes; then
23 ATANF_LIBM="$ATAN_LIBM"
26 dnl If the function is declared but does not appear to exist, it may be
27 dnl defined as an inline function. In order to avoid a conflict, we have
28 dnl to define rpl_atanf, not atanf.
29 AC_CHECK_DECLS([atanf], [REPLACE_ATANF=1], , [[#include <math.h>]])
30 ATANF_LIBM="$ATAN_LIBM"
32 AC_SUBST([ATANF_LIBM])