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51 lines
1.9 KiB
C
51 lines
1.9 KiB
C
/* Copyright (C) 1991-2013 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <unistd.h>
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#include <sys/time.h>
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/* Schedule an alarm. In SECONDS seconds, the process will get a SIGALRM.
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If SECONDS is zero, any currently scheduled alarm will be cancelled.
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The function returns the number of seconds remaining until the last
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alarm scheduled would have signaled, or zero if there wasn't one.
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There is no return value to indicate an error, but you can set `errno'
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to 0 and check its value after calling `alarm', and this might tell you.
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The signal may come late due to processor scheduling. */
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unsigned int
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alarm (seconds)
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unsigned int seconds;
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{
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struct itimerval old, new;
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unsigned int retval;
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new.it_interval.tv_usec = 0;
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new.it_interval.tv_sec = 0;
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new.it_value.tv_usec = 0;
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new.it_value.tv_sec = (long int) seconds;
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if (__setitimer (ITIMER_REAL, &new, &old) < 0)
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return 0;
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retval = old.it_value.tv_sec;
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/* Round to the nearest second, but never report zero seconds when
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the alarm is still set. */
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if (old.it_value.tv_usec >= 500000
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|| (retval == 0 && old.it_value.tv_usec > 0))
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++retval;
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return retval;
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}
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libc_hidden_def (alarm)
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