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76 lines
2.5 KiB
C
76 lines
2.5 KiB
C
/* Sleep for a given number of seconds. POSIX.1 version.
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Copyright (C) 1991-2012 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 <time.h>
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#include <unistd.h>
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#include <errno.h>
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#include <sys/param.h>
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/* Make the process sleep for SECONDS seconds, or until a signal arrives
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and is not ignored. The function returns the number of seconds less
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than SECONDS which it actually slept (zero if it slept the full time).
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If a signal handler does a `longjmp' or modifies the handling of the
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SIGALRM signal while inside `sleep' call, the handling of the SIGALRM
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signal afterwards is undefined. There is no return value to indicate
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error, but if `sleep' returns SECONDS, it probably didn't work. */
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unsigned int
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__sleep (unsigned int seconds)
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{
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/* This is not necessary but some buggy programs depend on it. */
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if (__builtin_expect (seconds == 0, 0))
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{
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#ifdef CANCELLATION_P
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CANCELLATION_P (THREAD_SELF);
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#endif
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return 0;
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}
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int save_errno = errno;
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const unsigned int max
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= (unsigned int) (((unsigned long int) (~((time_t) 0))) >> 1);
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struct timespec ts = { 0, 0 };
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do
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{
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if (sizeof (ts.tv_sec) <= sizeof (seconds))
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{
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/* Since SECONDS is unsigned assigning the value to .tv_sec can
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overflow it. In this case we have to wait in steps. */
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ts.tv_sec += MIN (seconds, max);
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seconds -= (unsigned int) ts.tv_sec;
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}
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else
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{
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ts.tv_sec = (time_t) seconds;
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seconds = 0;
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}
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if (__nanosleep (&ts, &ts) < 0)
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/* We were interrupted.
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Return the number of (whole) seconds we have not yet slept. */
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return seconds + ts.tv_sec;
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}
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while (seconds > 0);
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__set_errno (save_errno);
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return 0;
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}
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weak_alias (__sleep, sleep)
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