xref: /titanic_41/usr/src/lib/libm/common/C/lgamma.c (revision dfa1896db444d8b104da7cb009f39f1a89a438aa)
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  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
23  */
24 /*
25  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
26  * Use is subject to license terms.
27  */
28 
29 #pragma weak __lgamma = lgamma
30 
31 #include "libm.h"
32 
33 extern int signgam;
34 
35 double
36 lgamma(double x) {
37 	double	g;
38 
39 	if (!finite(x))
40 		return (x * x);
41 
42 	g = rint(x);
43 	if (x == g && x <= 0.0) {
44 		signgam = 1;
45 		return (_SVID_libm_err(x, x, 15));
46 	}
47 
48 	g = __k_lgamma(x, &signgam);
49 	if (!finite(g))
50 	    g = _SVID_libm_err(x, x, 14);
51 	return (g);
52 }
53