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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.
* ====================================================
*/
/* double gamma(double x)
* Return the logarithm of the Gamma function of x or the Gamma function of x,
* depending on the library mode.
*/
#include <errno.h>
#include <math.h>
#include <math_private.h>
#include <math-svid-compat.h>
#include <libm-alias-double.h>
#if LIBM_SVID_COMPAT
double
__tgamma(double x)
{
int local_signgam;
double y = __ieee754_gamma_r(x,&local_signgam);
if(__glibc_unlikely (!isfinite (y) || y == 0)
&& (isfinite (x) || (isinf (x) && x < 0.0))
&& _LIB_VERSION != _IEEE_) {
if (x == 0.0)
return __kernel_standard(x,x,50); /* tgamma pole */
else if(__floor(x)==x&&x<0.0)
return __kernel_standard(x,x,41); /* tgamma domain */
else if (y == 0)
__set_errno (ERANGE); /* tgamma underflow */
else
return __kernel_standard(x,x,40); /* tgamma overflow */
}
return local_signgam < 0 ? -y : y;
}
libm_alias_double (__tgamma, tgamma)
#endif
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