1 /* 2 * Copyright (c) 1985, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)ualarm.c 8.1 (Berkeley) 6/4/93 30 */ 31 32 #include <sys/time.h> 33 #include <unistd.h> 34 35 #define USPS 1000000 /* # of microseconds in a second */ 36 37 /* 38 * Generate a SIGALRM signal in ``usecs'' microseconds. 39 * If ``reload'' is non-zero, keep generating SIGALRM 40 * every ``reload'' microseconds after the first signal. 41 */ 42 useconds_t 43 ualarm(useconds_t usecs, useconds_t reload) 44 { 45 struct itimerval new, old; 46 47 new.it_interval.tv_usec = reload % USPS; 48 new.it_interval.tv_sec = reload / USPS; 49 50 new.it_value.tv_usec = usecs % USPS; 51 new.it_value.tv_sec = usecs / USPS; 52 53 if (setitimer(ITIMER_REAL, &new, &old) == 0) 54 return (old.it_value.tv_sec * USPS + old.it_value.tv_usec); 55 56 return (-1); 57 } 58