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glibc  2.9
timer_gettime.c
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00001 /* Copyright (C) 2000, 2004 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003    Contributed by Kaz Kylheku <kaz@ashi.footprints.net>.
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public License as
00007    published by the Free Software Foundation; either version 2.1 of the
00008    License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; see the file COPYING.LIB.  If not,
00017    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
00018    Boston, MA 02111-1307, USA.  */
00019 
00020 #include <errno.h>
00021 #include <pthread.h>
00022 #include <time.h>
00023 
00024 #include "posix-timer.h"
00025 
00026 
00027 /* Get current value of timer TIMERID and store it in VLAUE.  */
00028 int
00029 timer_gettime (timerid, value)
00030      timer_t timerid;
00031      struct itimerspec *value;
00032 {
00033   struct timer_node *timer;
00034   struct timespec now, expiry;
00035   int retval = -1, armed = 0, valid;
00036   clock_t clock = 0;
00037 
00038   pthread_mutex_lock (&__timer_mutex);
00039 
00040   timer = timer_id2ptr (timerid);
00041   valid = timer_valid (timer);
00042 
00043   if (valid) {
00044     armed = timer->armed;
00045     expiry = timer->expirytime;
00046     clock = timer->clock;
00047     value->it_interval = timer->value.it_interval;
00048   }
00049 
00050   pthread_mutex_unlock (&__timer_mutex);
00051 
00052   if (valid)
00053     {
00054       if (armed)
00055        {
00056          clock_gettime (clock, &now);
00057          if (timespec_compare (&now, &expiry) < 0)
00058            timespec_sub (&value->it_value, &expiry, &now);
00059          else
00060            {
00061              value->it_value.tv_sec = 0;
00062              value->it_value.tv_nsec = 0;
00063            }
00064        }
00065       else
00066        {
00067          value->it_value.tv_sec = 0;
00068          value->it_value.tv_nsec = 0;
00069        }
00070 
00071       retval = 0;
00072     }
00073   else
00074     __set_errno (EINVAL);
00075 
00076   return retval;
00077 }