105 lines
4.8 KiB
C
105 lines
4.8 KiB
C
/****************************************************************************
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* libs/libc/time/nanosleep.c
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*
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* Copyright (C) 2017 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <time.h>
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nanosleep
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*
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* Description:
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* The nanosleep() function causes the current thread to be suspended from
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* execution until either the time interval specified by the rqtp argument
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* has elapsed or a signal is delivered to the calling thread and its
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* action is to invoke a signal-catching function or to terminate the
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* process. The suspension time may be longer than requested because the
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* argument value is rounded up to an integer multiple of the sleep
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* resolution or because of the scheduling of other activity by the
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* system. But, except for the case of being interrupted by a signal, the
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* suspension time will not be less than the time specified by rqtp, as
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* measured by the system clock, CLOCK_REALTIME.
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*
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* The use of the nanosleep() function has no effect on the action or
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* blockage of any signal.
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*
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* Input Parameters:
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* rqtp - The amount of time to be suspended from execution.
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* rmtp - If the rmtp argument is non-NULL, the timespec structure
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* referenced by it is updated to contain the amount of time
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* remaining in the interval (the requested time minus the time
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* actually slept)
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*
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* Returned Value:
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* If the nanosleep() function returns because the requested time has
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* elapsed, its return value is zero.
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*
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* If the nanosleep() function returns because it has been interrupted by
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* a signal, the function returns a value of -1 and sets errno to indicate
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* the interruption. If the rmtp argument is non-NULL, the timespec
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* structure referenced by it is updated to contain the amount of time
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* remaining in the interval (the requested time minus the time actually
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* slept). If the rmtp argument is NULL, the remaining time is not
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* returned.
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*
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* If nanosleep() fails, it returns a value of -1 and sets errno to
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* indicate the error. The nanosleep() function will fail if:
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*
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* EINTR - The nanosleep() function was interrupted by a signal.
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* EINVAL - The rqtp argument specified a nanosecond value less than
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* zero or greater than or equal to 1000 million.
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* ENOSYS - The nanosleep() function is not supported by this
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* implementation.
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*
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****************************************************************************/
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int nanosleep(FAR const struct timespec *rqtp, FAR struct timespec *rmtp)
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{
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/* Calling clock_nanosleep() with the value TIMER_ABSTIME not set in the
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* flags argument and with a clock_id of CLOCK_REALTIME is equivalent t
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* calling nanosleep() with the same rqtp and rmtp arguments.
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*/
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return clock_nanosleep(CLOCK_REALTIME, 0, rqtp, rmtp);
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}
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