1 /* @(#)w_gamma.c 5.1 93/09/24 */ 2 /* 3 * ==================================================== 4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 5 * 6 * Developed at SunPro, a Sun Microsystems, Inc. business. 7 * Permission to use, copy, modify, and distribute this 8 * software is freely granted, provided that this notice 9 * is preserved. 10 * ==================================================== 11 */ 12 13 #if defined(LIBM_SCCS) && !defined(lint) 14 static char rcsid[] = "$NetBSD: w_gamma.c,v 1.7 1995/11/20 22:06:43 jtc Exp $"; 15 #endif 16 17 /* double gamma(double x) 18 * Return the logarithm of the Gamma function of x. 19 * 20 * Method: call gamma_r 21 */ 22 23 #include "math.h" 24 #include "math_private.h" 25 26 extern int signgam; 27 28 double 29 gamma(double x) 30 { 31 #ifdef _IEEE_LIBM 32 return __ieee754_lgamma_r(x,&signgam); 33 #else 34 double y; 35 y = __ieee754_lgamma_r(x,&signgam); 36 if(_LIB_VERSION == _IEEE_) return y; 37 if(!finite(y)&&finite(x)) { 38 if(floor(x)==x&&x<=0.0) 39 return __kernel_standard(x,x,41); /* gamma pole */ 40 else 41 return __kernel_standard(x,x,40); /* gamma overflow */ 42 } else 43 return y; 44 #endif 45 } 46