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_COPYSIGNF],
10 AC_REQUIRE([gl_MATH_H_DEFAULTS])
11 AC_REQUIRE([AC_CANONICAL_HOST])
13 dnl Persuade glibc <math.h> to declare copysignf().
14 AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
16 dnl Determine COPYSIGNF_LIBM.
17 gl_MATHFUNC([copysignf], [float], [(float, float)],
22 float copysignf (float, float);
24 if test $gl_cv_func_copysignf_no_libm = yes \
25 || test $gl_cv_func_copysignf_in_libm = yes; then
27 dnl Also check whether it's declared.
28 dnl IRIX 6.5 has copysignf() in libm but doesn't declare it in <math.h>.
29 AC_CHECK_DECL([copysignf], , [HAVE_DECL_COPYSIGNF=0], [[#include <math.h>]])
33 dnl On HP-UX 11.31/ia64, cc has a built-in for copysignf that redirects
34 dnl to the symbol '_copysignf', defined in libm, not libc.
36 hpux*) COPYSIGNF_LIBM='-lm' ;;
40 AC_SUBST([COPYSIGNF_LIBM])