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/* Base 10 logarithmic function.
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 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>
#if HAVE_SAME_LONG_DOUBLE_AS_DOUBLE
long double
log10l (long double x)
{
return log10 (x);
}
#elif HAVE_LOG10L
# include <float.h>
long double
log10l (long double x)
# undef log10l
{
/* Work around the OSF/1 5.1 bug. */
if (x == 0.0L)
/* Return -Infinity. */
return -1.0L / 0.0L;
{
long double y = log10l (x);
# ifdef __sgi
/* Normalize the +Infinity value. */
if (y > LDBL_MAX)
y = 1.0L / 0.0L;
# endif
return y;
}
}
#else
/* 1 / log(10) */
static const long double inv_log10 =
0.43429448190325182765112891891660508229439700580366656611445378316586464920887L;
long double
log10l (long double x)
{
return logl (x) * inv_log10;
}
#endif
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