103 lines
4.3 KiB
C
103 lines
4.3 KiB
C
/****************************************************************************
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* libs/libc/time/lib_nanosleep.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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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 <errno.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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int ret;
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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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* As clock_nanosleep() method return errno on fail, which is not
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* compatible with nanosleep(), the nanosleep() need to return -1 on fail,
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* so we need to convert the return value.
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*/
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ret = clock_nanosleep(CLOCK_REALTIME, 0, rqtp, rmtp);
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if (ret != 0)
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{
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set_errno(ret);
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ret = ERROR;
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}
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return ret;
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}
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