usr/src/lib/libc/port/gen/ualarm.c

   1 /*
   2  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
   3  * Use is subject to license terms.
   4  */
   5
   6 /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
   7 /*        All Rights Reserved   */
   8
   9 /*
  10  * Copyright (c) 1985 Regents of the University of California.
  11  * All rights reserved.  The Berkeley software License Agreement
  12  * specifies the terms and conditions for redistribution.
  13  */
  14
  15 #pragma ident   "%Z%%M% %I%     %E% SMI"
  16
  17 #include "lint.h"
  18 #include <sys/types.h>
  19 #include <sys/time.h>
  20 #include <unistd.h>
  21
  22 #define USPS    1000000         /* # of microseconds in a second */
  23
  24 /*
  25  * Generate a SIGALRM signal in ``usecs'' microseconds.
  26  * If ``reload'' is non-zero, keep generating SIGALRM
  27  * every ``reload'' microseconds after the first signal.
  28  */
  29 useconds_t
  30 ualarm(useconds_t usecs, useconds_t reload)
  31 {
  32         struct itimerval new, old;
  33
  34         new.it_interval.tv_usec = reload % USPS;
  35         new.it_interval.tv_sec = reload / USPS;
  36
  37         new.it_value.tv_usec = usecs % USPS;
  38         new.it_value.tv_sec = usecs / USPS;
  39
  40         if (setitimer(ITIMER_REAL, &new, &old) != 0)
  41                 return (0);     /* no errors are defined */
  42         return (old.it_value.tv_sec * USPS + old.it_value.tv_usec);
  43 }