1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 
  22 /*
  23  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  24  */
  25 
  26 /*
  27  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
  28  * Use is subject to license terms.
  29  */
  30 
  31 #pragma weak __gamma = gamma
  32 
  33 #include "libm.h"
  34 
  35 extern int signgam;
  36 
  37 double
  38 gamma(double x)
  39 {
  40         double g;
  41 
  42         if (!finite(x))
  43                 return (x * x);
  44 
  45         g = rint(x);
  46 
  47         if (x == g && x <= 0.0) {
  48                 signgam = 1;
  49                 return (_SVID_libm_err(x, x, 41));
  50         }
  51 
  52         g = __k_lgamma(x, &signgam);
  53 
  54         if (!finite(g))
  55                 g = _SVID_libm_err(x, x, 40);
  56 
  57         return (g);
  58 }