xref: /titanic_51/usr/src/lib/libc/port/gen/clock.c (revision 88447a05f537aabe9a1bc3d5313f22581ec992a7)
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 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1988 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 #pragma ident	"%Z%%M%	%I%	%E% SMI"
31 
32 #include "lint.h"
33 #include <sys/types.h>
34 #include <sys/times.h>
35 #include <time.h>
36 #include <sys/param.h>	/* for HZ (clock frequency in Hz) */
37 
38 #define	TIMES(B)	(B.tms_utime+B.tms_stime+B.tms_cutime+B.tms_cstime)
39 
40 
41 clock_t
42 clock(void)
43 {
44 	struct tms buffer;
45 	static int Hz = 0;
46 	static clock_t first;
47 	extern int gethz(void);		/* XXX should be in a header file! */
48 
49 	if (times(&buffer) == (clock_t)-1)
50 		return ((clock_t)-1);
51 	if (Hz == 0) {
52 		if ((Hz = gethz()) == 0)
53 			Hz = HZ;
54 		first = TIMES(buffer);
55 	}
56 
57 	return ((TIMES(buffer) - first) * (CLOCKS_PER_SEC/Hz));
58 }
59