lib/libc/gen/ualarm.c

   1 /*      $NetBSD: ualarm.c,v 1.11 2012/06/25 22:32:44 abs Exp $  */
   2
   3 /*
   4  * Copyright (c) 1985, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 #if 0
  35 static char sccsid[] = "@(#)ualarm.c    8.1 (Berkeley) 6/4/93";
  36 #else
  37 __RCSID("$NetBSD: ualarm.c,v 1.11 2012/06/25 22:32:44 abs Exp $");
  38 #endif
  39 #endif /* LIBC_SCCS and not lint */
  40
  41 #include "namespace.h"
  42 #include <sys/time.h>
  43 #include <unistd.h>
  44
  45 #ifdef __weak_alias
  46 __weak_alias(ualarm,_ualarm)
  47 #endif
  48
  49 #define USPS    1000000         /* # of microseconds in a second */
  50
  51 /*
  52  * Generate a SIGALRM signal in ``usecs'' microseconds.
  53  * If ``reload'' is non-zero, keep generating SIGALRM
  54  * every ``reload'' microseconds after the first signal.
  55  */
  56 useconds_t
  57 ualarm(useconds_t usecs, useconds_t reload)
  58 {
  59         struct itimerval new, old;
  60
  61         new.it_interval.tv_usec = reload % USPS;
  62         new.it_interval.tv_sec = reload / USPS;
  63
  64         new.it_value.tv_usec = usecs % USPS;
  65         new.it_value.tv_sec = usecs / USPS;
  66
  67         if (setitimer(ITIMER_REAL, &new, &old) == 0)
  68                 return (useconds_t)(old.it_value.tv_sec * USPS +
  69                     old.it_value.tv_usec);
  70
  71         return (useconds_t)-1;
  72 }