gen/FreeBSD/ualarm.c

   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. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #if defined(LIBC_SCCS) && !defined(lint)
  35 static char sccsid[] = "@(#)ualarm.c    8.1 (Berkeley) 6/4/93";
  36 #endif /* LIBC_SCCS and not lint */
  37 #include <sys/cdefs.h>
  38 __FBSDID("$FreeBSD: src/lib/libc/gen/ualarm.c,v 1.4 2002/12/29 00:59:09 mike Exp $");
  39
  40 #include <sys/time.h>
  41 #include <unistd.h>
  42
  43 #define USPS    1000000         /* # of microseconds in a second */
  44
  45 /*
  46  * Generate a SIGALRM signal in ``usecs'' microseconds.
  47  * If ``reload'' is non-zero, keep generating SIGALRM
  48  * every ``reload'' microseconds after the first signal.
  49  */
  50 useconds_t
  51 ualarm(usecs, reload)
  52         useconds_t usecs;
  53         useconds_t reload;
  54 {
  55         struct itimerval new, old;
  56
  57         new.it_interval.tv_usec = reload % USPS;
  58         new.it_interval.tv_sec = reload / USPS;
  59
  60         new.it_value.tv_usec = usecs % USPS;
  61         new.it_value.tv_sec = usecs / USPS;
  62
  63         if (setitimer(ITIMER_REAL, &new, &old) == 0)
  64                 return (old.it_value.tv_sec * USPS + old.it_value.tv_usec);
  65         /* else */
  66                 return (-1);
  67 }