| /**************************************************************************** |
| * libs/libc/time/lib_nanosleep.c |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. The |
| * ASF licenses this file to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance with the |
| * License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| * License for the specific language governing permissions and limitations |
| * under the License. |
| * |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Included Files |
| ****************************************************************************/ |
| |
| #include <nuttx/config.h> |
| |
| #include <errno.h> |
| #include <time.h> |
| |
| /**************************************************************************** |
| * Public Functions |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Name: nanosleep |
| * |
| * Description: |
| * The nanosleep() function causes the current thread to be suspended from |
| * execution until either the time interval specified by the rqtp argument |
| * has elapsed or a signal is delivered to the calling thread and its |
| * action is to invoke a signal-catching function or to terminate the |
| * process. The suspension time may be longer than requested because the |
| * argument value is rounded up to an integer multiple of the sleep |
| * resolution or because of the scheduling of other activity by the |
| * system. But, except for the case of being interrupted by a signal, the |
| * suspension time will not be less than the time specified by rqtp, as |
| * measured by the system clock, CLOCK_REALTIME. |
| * |
| * The use of the nanosleep() function has no effect on the action or |
| * blockage of any signal. |
| * |
| * Input Parameters: |
| * rqtp - The amount of time to be suspended from execution. |
| * rmtp - If the rmtp argument is non-NULL, the timespec structure |
| * referenced by it is updated to contain the amount of time |
| * remaining in the interval (the requested time minus the time |
| * actually slept) |
| * |
| * Returned Value: |
| * If the nanosleep() function returns because the requested time has |
| * elapsed, its return value is zero. |
| * |
| * If the nanosleep() function returns because it has been interrupted by |
| * a signal, the function returns a value of -1 and sets errno to indicate |
| * the interruption. If the rmtp argument is non-NULL, the timespec |
| * structure referenced by it is updated to contain the amount of time |
| * remaining in the interval (the requested time minus the time actually |
| * slept). If the rmtp argument is NULL, the remaining time is not |
| * returned. |
| * |
| * If nanosleep() fails, it returns a value of -1 and sets errno to |
| * indicate the error. The nanosleep() function will fail if: |
| * |
| * EINTR - The nanosleep() function was interrupted by a signal. |
| * EINVAL - The rqtp argument specified a nanosecond value less than |
| * zero or greater than or equal to 1000 million. |
| * ENOSYS - The nanosleep() function is not supported by this |
| * implementation. |
| * |
| ****************************************************************************/ |
| |
| int nanosleep(FAR const struct timespec *rqtp, FAR struct timespec *rmtp) |
| { |
| int ret; |
| |
| /* Calling clock_nanosleep() with the value TIMER_ABSTIME not set in the |
| * flags argument and with a clock_id of CLOCK_REALTIME is equivalent t |
| * calling nanosleep() with the same rqtp and rmtp arguments. |
| * As clock_nanosleep() method return errno on fail, which is not |
| * compatible with nanosleep(), the nanosleep() need to return -1 on fail, |
| * so we need to convert the return value. |
| */ |
| |
| ret = clock_nanosleep(CLOCK_REALTIME, 0, rqtp, rmtp); |
| if (ret != 0) |
| { |
| set_errno(ret); |
| ret = ERROR; |
| } |
| |
| return ret; |
| } |