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glibc  2.9
ualarm.c
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00001 /* Copyright (C) 1991, 1997, 1999, 2000 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.  */
00018 
00019 #include <sys/time.h>
00020 #include <unistd.h>
00021 
00022 /* Set an alarm to go off (generating a SIGALRM signal) in VALUE microseconds.
00023    If INTERVAL is nonzero, when the alarm goes off, the timer is reset to go
00024    off every INTERVAL microseconds thereafter.
00025 
00026    Returns the number of microseconds remaining before the alarm.  */
00027 useconds_t
00028 ualarm (value, interval)
00029      useconds_t value;
00030      useconds_t interval;
00031 {
00032   struct itimerval timer, otimer;
00033 
00034   timer.it_value.tv_sec = 0;
00035   timer.it_value.tv_usec = value;
00036   timer.it_interval.tv_sec = 0;
00037   timer.it_interval.tv_usec = interval;
00038 
00039   if (__setitimer (ITIMER_REAL, &timer, &otimer) < 0)
00040     return -1;
00041 
00042   return (otimer.it_value.tv_sec * 1000000) + otimer.it_value.tv_usec;
00043 }