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/* @(#)w_gamma.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_gamma.c,v 1.7 1995/11/20 22:06:43 jtc Exp $";

#endif

/* double gamma(double x)

 * Return the logarithm of the Gamma function of x.

 *

 * Method: call gamma_r

 */

#include "math.h"

#include "math_private.h"

extern int signgam;

#ifdef __STDC__

        double gamma(double x)

#else

        double gamma(x)

        double x;

#endif

{

#ifdef _IEEE_LIBM

        return __ieee754_lgamma_r(x,&signgam);

#else

        double y;

        y = __ieee754_lgamma_r(x,&signgam);

        if(_LIB_VERSION == _IEEE_) return y;

        if(!finite(y)&&finite(x)) {

            if(floor(x)==x&&x<=0.0)

                return __kernel_standard(x,x,41); /* gamma pole */

            else

                return __kernel_standard(x,x,40); /* gamma overflow */

        } else

            return y;

#endif

}