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/* Natural logarithmic function.
Copyright (C) 2011-2021 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 <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include <math.h>
float
logf (float x)
#undef logf
{
#if HAVE_LOGF
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 logf (x);
#else
return (float) log ((double) x);
#endif
}
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