58 lines
2.3 KiB
C
58 lines
2.3 KiB
C
/* $OpenBSD: ualarm.c,v 1.7 2005/08/08 08:05:34 espie Exp $ */
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/*
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* Copyright (c) 1985, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/types.h>
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#include <sys/time.h>
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#include <unistd.h>
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#define USPS 1000000 /* # of microseconds in a second */
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/*
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* Generate a SIGALRM signal in ``usecs'' microseconds.
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* If ``reload'' is non-zero, keep generating SIGALRM
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* every ``reload'' microseconds after the first signal.
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*/
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useconds_t
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ualarm(useconds_t usecs, useconds_t reload)
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{
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struct itimerval new, old;
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new.it_interval.tv_usec = reload % USPS;
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new.it_interval.tv_sec = reload / USPS;
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new.it_value.tv_usec = usecs % USPS;
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new.it_value.tv_sec = usecs / USPS;
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if (setitimer(ITIMER_REAL, &new, &old) == 0)
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return ((useconds_t)(old.it_value.tv_sec * USPS + old.it_value.tv_usec));
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/* else */
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return ((useconds_t)-1);
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}
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