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From: jon@hitachi.uucp (Jon Ryshpan)
Newsgroups: comp.unix.sysv386
Subject: Timing short intervals
Message-ID: <695@hitachi.uucp>
Date: 10 Jun 91 23:25:29 GMT
Reply-To: jon@hitachi.UUCP (Jon Ryshpan)
Distribution: na
Organization: Hitachi America - Semiconductor & IC Div.
Lines: 40

Does anyone know how to time an interval of less than one second under
ISC Unix (Version 2.2)?  I tried setitimer(), which is in the library
/usr/lib/libinet.a; but it doesn't seem to work as described in the
BSD 4.2 documentation; and it isn't described at all in the Interactive
documentation.

	/* This is from /usr/include/time.h */

struct timeval {
	long	tv_sec;		/* seconds */
	long	tv_usec;	/* and microseconds */
};

#define	ITIMER_REAL	0
#define	ITIMER_VIRTUAL	1
#define	ITIMER_PROF	2

struct	itimerval {
	struct	timeval it_interval;	/* timer interval */
	struct	timeval it_value;	/* current value */
};

	/* This is from my program. */

struct itimerval Value;
setitimer( ITIMER_REAL, &Value, 0 );

	/* Program ends */

My program ignores Value.it_value.tv_usec completely.  It pays attention 
to Value.it_value.tv_sec; but this gives a resolution of only one second.

Ideas anyone?

Please reply BY MAIL.  I don't have time to follow this group.
	     ^^ ^^^^

Many Thanks:	

Jonathan Ryshpan		<...!uunet!hitachi!jon>