log10.c 1.13 KB
Newer Older
1
/* Base 10 logarithmic function.
Paul Eggert's avatar
Paul Eggert committed
2
   Copyright (C) 2012-2016 Free Software Foundation, Inc.
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

   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>

double
log10 (double x)
#undef log10
{
26 27 28 29 30 31 32 33 34 35 36
  if (x <= 0.0)
    {
      /* Work around the OSF/1 5.1 bug.  */
      if (x == 0.0)
        /* Return -Infinity.  */
        return -1.0 / 0.0;
      /* Work around the NetBSD 5.1, Solaris 11 2011-11 bug.  */
      else /* x < 0.0 */
        /* Return NaN.  */
        return 0.0 / 0.0;
    }
37 38
  return log10 (x);
}