diff options
Diffstat (limited to 'lib/log.c')
-rw-r--r-- | lib/log.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/lib/log.c b/lib/log.c new file mode 100644 index 000000000..2ec8cb9d5 --- /dev/null +++ b/lib/log.c @@ -0,0 +1,38 @@ +/* Logarithm. + Copyright (C) 2012-2017 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU Lesser 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 Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + +#include <config.h> + +/* Specification. */ +#include <math.h> + +double +log (double x) +#undef log +{ + 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; + } + return log (x); +} |