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/* $OpenBSD: hertz.c,v 1.4 2003/06/03 02:56:08 millert Exp $ */
/* $NetBSD: hertz.c,v 1.5 1995/04/19 07:16:03 cgd Exp $ */
/*
* Copyright (c) 1983, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
#if 0
static char sccsid[] = "@(#)hertz.c 8.1 (Berkeley) 6/6/93";
#else
static char rcsid[] = "$OpenBSD: hertz.c,v 1.4 2003/06/03 02:56:08 millert Exp $";
#endif
#endif /* not lint */
#include <sys/time.h>
/*
* discover the tick frequency of the machine
* if something goes wrong, we return 0, an impossible hertz.
*/
#define HZ_WRONG 0
int
hertz()
{
struct itimerval tim;
tim.it_interval.tv_sec = 0;
tim.it_interval.tv_usec = 1;
tim.it_value.tv_sec = 0;
tim.it_value.tv_usec = 0;
setitimer(ITIMER_REAL, &tim, 0);
setitimer(ITIMER_REAL, 0, &tim);
if (tim.it_interval.tv_usec < 2)
return(HZ_WRONG);
return (1000000 / tim.it_interval.tv_usec);
}
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