glibc/math/w_lgamma.c

61 lines
1.6 KiB
C

/* @(#)w_lgamma.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.
* ====================================================
*/
#if defined(LIBM_SCCS) && !defined(lint)
static char rcsid[] = "$NetBSD: w_lgamma.c,v 1.6 1995/05/10 20:49:24 jtc Exp $";
#endif
/* double lgamma(double x)
* Return the logarithm of the Gamma function of x.
*
* Method: call __ieee754_lgamma_r
*/
#include "math.h"
#include "math_private.h"
#ifdef __STDC__
double __lgamma(double x)
#else
double __lgamma(x)
double x;
#endif
{
#ifdef _IEEE_LIBM
return __ieee754_lgamma_r(x,&signgam);
#else
double y;
int local_signgam;
y = __ieee754_lgamma_r(x,&local_signgam);
if (_LIB_VERSION != _ISOC_)
/* ISO C99 does not define the global variable. */
signgam = local_signgam;
if(_LIB_VERSION == _IEEE_) return y;
if(!__finite(y)&&__finite(x)) {
if(__floor(x)==x&&x<=0.0)
return __kernel_standard(x,x,15); /* lgamma pole */
else
return __kernel_standard(x,x,14); /* lgamma overflow */
} else
return y;
#endif
}
weak_alias (__lgamma, lgamma)
strong_alias (__lgamma, __gamma)
weak_alias (__gamma, gamma)
#ifdef NO_LONG_DOUBLE
strong_alias (__lgamma, __lgammal)
weak_alias (__lgamma, lgammal)
strong_alias (__gamma, __gammal)
weak_alias (__gamma, gammal)
#endif