xref: /netbsd-src/lib/libc/gen/clock.c (revision 17bda641e50b32c020a8f3cf38e47ff50ff426d4)
1 /*
2  * Copyright (c) 1989 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 /*static char sccsid[] = "from: @(#)clock.c	5.4 (Berkeley) 8/27/90";*/
36 static char rcsid[] = "$Id: clock.c,v 1.3 1993/08/17 20:37:59 jtc Exp $";
37 #endif /* LIBC_SCCS and not lint */
38 
39 #include <sys/param.h>
40 #include <sys/time.h>
41 #include <sys/resource.h>
42 
43 /*
44  * Convert usec to clock ticks; could do (usec * CLOCKS_PER_SEC) / 1000000,
45  * but this would overflow if we switch to nanosec.
46  */
47 #define	CONVTCK(r)	(r.tv_sec * CLOCKS_PER_SEC + \
48 			 r.tv_usec / (1000000 / CLOCKS_PER_SEC))
49 
50 clock_t
51 clock()
52 {
53 	struct rusage ru;
54 
55 	if (getrusage(RUSAGE_SELF, &ru))
56 		return ((clock_t) -1);
57 	return((clock_t)((CONVTCK(ru.ru_utime) + CONVTCK(ru.ru_stime))));
58 }
59