newlib-cygwin/newlib/libm/math/w_tgamma.c

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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 "fdlibm.h"
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#include <errno.h>
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#ifndef _DOUBLE_IS_32BITS
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#ifdef __STDC__
double tgamma(double x)
#else
double tgamma(x)
double x;
#endif
{
double y;
y = __ieee754_tgamma(x);
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#ifdef _IEEE_LIBM
return y;
#else
if(_LIB_VERSION == _IEEE_) return y;
if(!finite(y)) {
if(x < 0.0 && floor(x)==x)
errno = EDOM;
else if (finite(x))
errno = ERANGE;
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}
return y;
#endif
}
#endif /* defined(_DOUBLE_IS_32BITS) */