view lib/log10f.c @ 16747:676471a1cb33

log10f-ieee: Work around test failure on NetBSD 5.1. * m4/log10f-ieee.m4: New file. * m4/log10f.m4 (gl_FUNC_LOG10F): If gl_FUNC_LOG10F_IEEE is present, test whether log10f works with a negative argument. Replace it if not. * lib/log10f.c (log10f): For negative arguments, return NaN. * modules/log10f-ieee (Files): Add m4/log10f-ieee.m4. (configure.ac): Invoke gl_FUNC_LOG10F_IEEE. * doc/posix-functions/log10f.texi: Mention the log10f-ieee module.
author Bruno Haible <bruno@clisp.org>
date Sun, 01 Apr 2012 17:56:33 +0200
parents 6828b991e3b9
children e542fd46ad6f
line wrap: on
line source

/* Base 10 logarithmic function.
   Copyright (C) 2011-2012 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include <config.h>

/* Specification.  */
#include <math.h>

float
log10f (float x)
#undef log10f
{
#if HAVE_LOG10F
  if (x <= 0.0f)
    {
      /* Work around the OSF/1 5.1 bug.  */
      if (x == 0.0f)
        /* Return -Infinity.  */
        return -1.0f / 0.0f;
      /* Work around the NetBSD 5.1 bug.  */
      else /* x < 0.0 */
        /* Return NaN.  */
        return 0.0f / 0.0f;
    }
  return log10f (x);
#else
  return (float) log10 ((double) x);
#endif
}