Update Gnulib to v0.0-7509-g98a2286.

[bpt/guile.git] / lib / log.c

diff --git a/lib/log.c b/lib/log.c
new file mode 100644 (file)
index 0000000..9ec5eae
--- /dev/null
+++ b/lib/log.c
@@ -0,0 +1,38 @@
+/* Logarithm.
+   Copyright (C) 2012 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);
+}