incubator-nuttx/sched/signal/sig_pause.c

94 lines
3.0 KiB
C

/****************************************************************************
* sched/signal/sig_pause.c
*
* SPDX-License-Identifier: Apache-2.0
*
* 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 <unistd.h>
#include <signal.h>
#include <errno.h>
#include <nuttx/signal.h>
#include <nuttx/cancelpt.h>
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: pause
*
* Description:
* The pause() function will suspend the calling thread until delivery of a
* non-blocked signal.
*
* Input Parameters:
* None
*
* Returned Value:
* Since pause() suspends thread execution indefinitely unless interrupted
* a signal, there is no successful completion return value. A value of -1
* will always be returned and errno set to indicate the error (EINTR).
*
* POSIX compatibility:
* In the POSIX description of this function is the pause() function will
* suspend the calling thread until delivery of a signal whose action is
* either to execute a signal-catching function or to terminate the
* process. This implementation only waits for any non-blocked signal
* to be received.
*
****************************************************************************/
int pause(void)
{
sigset_t set;
int ret;
/* pause() is a cancellation point */
enter_cancellation_point();
/* Set up for the sleep. Using the empty set means that we are not
* waiting for any particular signal. However, any unmasked signal
* can still awaken sigtimedwait().
*/
sigemptyset(&set);
/* sigtwaitinfo() cannot succeed. It should always return error EINTR
* meaning that some unblocked signal was caught.
*/
ret = nxsig_waitinfo(&set, NULL);
if (ret < 0)
{
set_errno(-ret);
ret = ERROR;
}
leave_cancellation_point();
return ret;
}