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/* $OpenBSD: ualarm.c,v 1.7 2005/08/08 08:05:34 espie Exp $ */
/*
* Copyright (c) 1985, 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.
*/
#include <sys/types.h>
#include <sys/time.h>
#include <unistd.h>
#define USPS 1000000 /* # of microseconds in a second */
/*
* Generate a SIGALRM signal in ``usecs'' microseconds.
* If ``reload'' is non-zero, keep generating SIGALRM
* every ``reload'' microseconds after the first signal.
*/
useconds_t
ualarm(useconds_t usecs, useconds_t reload)
{
struct itimerval new, old;
new.it_interval.tv_usec = reload % USPS;
new.it_interval.tv_sec = reload / USPS;
new.it_value.tv_usec = usecs % USPS;
new.it_value.tv_sec = usecs / USPS;
if (setitimer(ITIMER_REAL, &new, &old) == 0)
return ((useconds_t)(old.it_value.tv_sec * USPS + old.it_value.tv_usec));
/* else */
return ((useconds_t)-1);
}
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