2 dnl Copyright (C) 2011-2013 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_LOG10F],
9 m4_divert_text([DEFAULTS], [gl_log10f_required=plain])
10 AC_REQUIRE([gl_MATH_H_DEFAULTS])
11 AC_REQUIRE([gl_FUNC_LOG10])
13 dnl Persuade glibc <math.h> to declare log10f().
14 AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
16 dnl Test whether log10f() exists. Assume that log10f(), if it exists, is
17 dnl defined in the same library as log10().
19 LIBS="$LIBS $LOG10_LIBM"
20 AC_CHECK_FUNCS([log10f])
22 if test $ac_cv_func_log10f = yes; then
23 LOG10F_LIBM="$LOG10_LIBM"
26 LIBS="$LIBS $LOG10F_LIBM"
29 case "$gl_cv_func_log10f_works" in
31 *) REPLACE_LOG10F=1 ;;
34 m4_ifdef([gl_FUNC_LOG10F_IEEE], [
35 if test $gl_log10f_required = ieee && test $REPLACE_LOG10F = 0; then
36 AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
37 AC_CACHE_CHECK([whether log10f works according to ISO C 99 with IEC 60559],
38 [gl_cv_func_log10f_ieee],
41 LIBS="$LIBS $LOG10F_LIBM"
44 #ifndef __NO_MATH_INLINES
45 # define __NO_MATH_INLINES 1 /* for glibc */
48 /* Compare two numbers with ==.
49 This is a separate function because IRIX 6.5 "cc -O" miscompiles an
52 numeric_equal (float x, float y)
56 static float dummy (float x) { return 0; }
57 int main (int argc, char *argv[])
59 float (*my_log10f) (float) = argc ? log10f : dummy;
60 /* Test log10f(negative).
61 This test fails on NetBSD 5.1. */
62 float y = my_log10f (-1.0f);
63 if (numeric_equal (y, y))
68 [gl_cv_func_log10f_ieee=yes],
69 [gl_cv_func_log10f_ieee=no],
71 # Guess yes on glibc systems.
72 *-gnu*) gl_cv_func_log10f_ieee="guessing yes" ;;
73 # If we don't know, assume the worst.
74 *) gl_cv_func_log10f_ieee="guessing no" ;;
79 case "$gl_cv_func_log10f_ieee" in
81 *) REPLACE_LOG10F=1 ;;
88 if test $HAVE_LOG10F = 0 || test $REPLACE_LOG10F = 1; then
89 dnl Find libraries needed to link lib/log10f.c.
90 if test $HAVE_LOG10F = 0; then
91 LOG10F_LIBM="$LOG10_LIBM"
94 AC_SUBST([LOG10F_LIBM])
97 dnl Test whether log10f() works.
98 dnl On OSF/1 5.1, log10f(-0.0f) is NaN.
99 AC_DEFUN([gl_FUNC_LOG10F_WORKS],
101 AC_REQUIRE([AC_PROG_CC])
102 AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
103 AC_CACHE_CHECK([whether log10f works], [gl_cv_func_log10f_works],
119 [gl_cv_func_log10f_works=yes],
120 [gl_cv_func_log10f_works=no],
122 osf*) gl_cv_func_log10f_works="guessing no";;
123 *) gl_cv_func_log10f_works="guessing yes";;