diff options
Diffstat (limited to 'm4/log10.m4')
| -rw-r--r-- | m4/log10.m4 | 48 |
1 files changed, 47 insertions, 1 deletions
diff --git a/m4/log10.m4 b/m4/log10.m4 index ab066cc071..08122ca80f 100644 --- a/m4/log10.m4 +++ b/m4/log10.m4 @@ -1,4 +1,4 @@ -# log10.m4 serial 2 +# log10.m4 serial 3 dnl Copyright (C) 2011-2012 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, @@ -6,6 +6,7 @@ dnl with or without modifications, as long as this notice is preserved. AC_DEFUN([gl_FUNC_LOG10], [ + m4_divert_text([DEFAULTS], [gl_log10_required=plain]) AC_REQUIRE([gl_MATH_H_DEFAULTS]) dnl Determine LOG10_LIBM. @@ -19,6 +20,51 @@ AC_DEFUN([gl_FUNC_LOG10], *yes) ;; *) REPLACE_LOG10=1 ;; esac + + m4_ifdef([gl_FUNC_LOG10_IEEE], [ + if test $gl_log10_required = ieee && test $REPLACE_LOG10 = 0; then + AC_CACHE_CHECK([whether log10 works according to ISO C 99 with IEC 60559], + [gl_cv_func_log10_ieee], + [ + save_LIBS="$LIBS" + LIBS="$LIBS $LOG10_LIBM" + AC_RUN_IFELSE( + [AC_LANG_SOURCE([[ +#ifndef __NO_MATH_INLINES +# define __NO_MATH_INLINES 1 /* for glibc */ +#endif +#include <math.h> +/* Compare two numbers with ==. + This is a separate function because IRIX 6.5 "cc -O" miscompiles an + 'x == x' test. */ +static int +numeric_equal (double x, double y) +{ + return x == y; +} +static double dummy (double x) { return 0; } +int main (int argc, char *argv[]) +{ + double (*my_log10) (double) = argc ? log10 : dummy; + /* Test log10(negative). + This test fails on NetBSD 5.1, Solaris 11 2011-11. */ + double y = my_log10 (-1.0); + if (numeric_equal (y, y)) + return 1; + return 0; +} + ]])], + [gl_cv_func_log10_ieee=yes], + [gl_cv_func_log10_ieee=no], + [gl_cv_func_log10_ieee="guessing no"]) + LIBS="$save_LIBS" + ]) + case "$gl_cv_func_log10_ieee" in + *yes) ;; + *) REPLACE_LOG10=1 ;; + esac + fi + ]) ]) dnl Test whether log10() works. |