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/* @(#)w_log10.c 5.1 93/09/24 */
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
/*
FUNCTION
<<log10>>, <<log10f>>---base 10 logarithms
INDEX
log10
INDEX
log10f
SYNOPSIS
#include <math.h>
double log10(double <[x]>);
float log10f(float <[x]>);
DESCRIPTION
<<log10>> returns the base 10 logarithm of <[x]>.
It is implemented as <<log(<[x]>) / log(10)>>.
<<log10f>> is identical, save that it takes and returns <<float>> values.
RETURNS
<<log10>> and <<log10f>> return the calculated value.
See the description of <<log>> for information on errors.
PORTABILITY
<<log10>> is ANSI C. <<log10f>> is an extension.
*/
/*
* wrapper log10(X)
*/
#include "fdlibm.h"
#include <errno.h>
#ifndef _DOUBLE_IS_32BITS
#ifdef __STDC__
double log10(double x) /* wrapper log10 */
#else
double log10(x) /* wrapper log10 */
double x;
#endif
{
#ifdef _IEEE_LIBM
return __ieee754_log10(x);
#else
double z;
struct exception exc;
z = __ieee754_log10(x);
if(_LIB_VERSION == _IEEE_ || isnan(x)) return z;
if(x<=0.0) {
#ifndef HUGE_VAL
#define HUGE_VAL inf
double inf = 0.0;
SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */
#endif
exc.name = "log10";
exc.err = 0;
exc.arg1 = x;
exc.arg2 = x;
if (_LIB_VERSION == _SVID_)
exc.retval = -HUGE;
else
exc.retval = -HUGE_VAL;
if(x==0.0) {
/* log10(0) */
exc.type = SING;
if (_LIB_VERSION == _POSIX_)
errno = ERANGE;
else if (!matherr(&exc)) {
errno = ERANGE;
}
} else {
/* log10(x<0) */
exc.type = DOMAIN;
if (_LIB_VERSION == _POSIX_)
errno = EDOM;
else if (!matherr(&exc)) {
errno = EDOM;
}
exc.retval = nan("");
}
if (exc.err != 0)
errno = exc.err;
return exc.retval;
} else
return z;
#endif
}
#endif /* defined(_DOUBLE_IS_32BITS) */
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