xref: /original-bsd/lib/libc/gen/clock.c (revision bac379f5)
1 /*
2  * Copyright (c) 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * %sccs.include.redist.c%
6  */
7 
8 #if defined(LIBC_SCCS) && !defined(lint)
9 static char sccsid[] = "@(#)clock.c	8.1 (Berkeley) 06/04/93";
10 #endif /* LIBC_SCCS and not lint */
11 
12 #include <sys/param.h>
13 #include <sys/time.h>
14 #include <sys/resource.h>
15 
16 /*
17  * Convert usec to clock ticks; could do (usec * CLK_TCK) / 1000000,
18  * but this would overflow if we switch to nanosec.
19  */
20 #define	CONVTCK(r)	(r.tv_sec * CLK_TCK + r.tv_usec / (1000000 / CLK_TCK))
21 
22 clock_t
clock()23 clock()
24 {
25 	struct rusage ru;
26 
27 	if (getrusage(RUSAGE_SELF, &ru))
28 		return ((clock_t) -1);
29 	return((clock_t)((CONVTCK(ru.ru_utime) + CONVTCK(ru.ru_stime))));
30 }
31