math/w_lgamma.c

   1 /* @(#)w_lgamma.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_lgamma.c,v 1.6 1995/05/10 20:49:24 jtc Exp $";
  15 #endif
  16
  17 /* double lgamma(double x)
  18  * Return the logarithm of the Gamma function of x.
  19  *
  20  * Method: call __ieee754_lgamma_r
  21  */
  22
  23 #include <math.h>
  24 #include "math_private.h"
  25
  26 #ifdef __STDC__
  27         double __lgamma(double x)
  28 #else
  29         double __lgamma(x)
  30         double x;
  31 #endif
  32 {
  33 #ifdef _IEEE_LIBM
  34         return __ieee754_lgamma_r(x,&signgam);
  35 #else
  36         double y;
  37         int local_signgam = 0;
  38         y = __ieee754_lgamma_r(x,&local_signgam);
  39         if (_LIB_VERSION != _ISOC_)
  40           /* ISO C99 does not define the global variable.  */
  41           signgam = local_signgam;
  42         if(_LIB_VERSION == _IEEE_) return y;
  43         if(!__finite(y)&&__finite(x)) {
  44             if(__floor(x)==x&&x<=0.0)
  45                 return __kernel_standard(x,x,15); /* lgamma pole */
  46             else
  47                 return __kernel_standard(x,x,14); /* lgamma overflow */
  48         } else
  49             return y;
  50 #endif
  51 }
  52 weak_alias (__lgamma, lgamma)
  53 strong_alias (__lgamma, __gamma)
  54 weak_alias (__gamma, gamma)
  55 #ifdef NO_LONG_DOUBLE
  56 strong_alias (__lgamma, __lgammal)
  57 weak_alias (__lgamma, lgammal)
  58 strong_alias (__gamma, __gammal)
  59 weak_alias (__gamma, gammal)
  60 #endif