2 dnl Copyright (C) 2011-2012 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_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 $REPLACE_LOG10F = 0; then
36 AC_CACHE_CHECK([whether log10f works according to ISO C 99 with IEC 60559],
37 [gl_cv_func_log10f_ieee],
40 LIBS="$LIBS $LOGF_LIBM"
43 #ifndef __NO_MATH_INLINES
44 # define __NO_MATH_INLINES 1 /* for glibc */
47 /* Compare two numbers with ==.
48 This is a separate function because IRIX 6.5 "cc -O" miscompiles an
51 numeric_equal (float x, float y)
55 static float dummy (float x) { return 0; }
56 int main (int argc, char *argv[])
58 float (*my_log10f) (float) = argc ? log10f : dummy;
59 /* Test log10f(negative).
60 This test fails on NetBSD 5.1. */
61 float y = my_log10f (-1.0f);
62 if (numeric_equal (y, y))
67 [gl_cv_func_log10f_ieee=yes],
68 [gl_cv_func_log10f_ieee=no],
69 [gl_cv_func_log10f_ieee="guessing no"])
72 case "$gl_cv_func_log10f_ieee" in
74 *) REPLACE_LOG10F=1 ;;
81 if test $HAVE_LOG10F = 0 || test $REPLACE_LOG10F = 1; then
82 dnl Find libraries needed to link lib/log10f.c.
83 if test $HAVE_LOG10F = 0; then
84 LOG10F_LIBM="$LOG10_LIBM"
87 AC_SUBST([LOG10F_LIBM])
90 dnl Test whether log10f() works.
91 dnl On OSF/1 5.1, log10f(-0.0f) is NaN.
92 AC_DEFUN([gl_FUNC_LOG10F_WORKS],
94 AC_REQUIRE([AC_PROG_CC])
95 AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
96 AC_CACHE_CHECK([whether log10f works], [gl_cv_func_log10f_works],
112 [gl_cv_func_log10f_works=yes],
113 [gl_cv_func_log10f_works=no],
115 osf*) gl_cv_func_log10f_works="guessing no";;
116 *) gl_cv_func_log10f_works="guessing yes";;