98 lines
4.0 KiB
C
98 lines
4.0 KiB
C
/****************************************************************************
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* libs/libc/signal/sig_wait.c
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*
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* SPDX-License-Identifier: Apache-2.0
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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 <signal.h>
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#include <assert.h>
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#include <errno.h>
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: sigwait
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*
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* Description:
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* The sigwait() function selects a pending signal from set, atomically
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* clears it from the system's set of pending signals, and returns that
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* signal number in the location referenced by sig. If prior to the call
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* to sigwait() there are multiple pending instances of a single signal
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* number, it is implementation-dependent whether upon successful return
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* there are any remaining pending signals for that signal number. If the
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* implementation supports queued signals and there are multiple signals
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* queued for the signal number selected, the first such queued signal
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* causes a return from sigwait() and the remainder remain queued. If no
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* signal in set is pending at the time of the call, the thread is
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* suspended until one or more becomes pending. The signals defined by set
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* will been blocked at the time of the call to sigwait(); otherwise the
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* behavior is undefined. The effect of sigwait() on the signal actions
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* for the signals in set is unspecified.
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*
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* If more than one thread is using sigwait() to wait for the same
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* signal, no more than one of these threads will return from sigwait()
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* with the signal number. Which thread returns from sigwait() if more
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* than a single thread is waiting is unspecified.
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*
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* Should any of the multiple pending signals in the range SIGRTMIN to
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* SIGRTMAX be selected, it shall be the lowest numbered one. The selection
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* order between realtime and non-realtime signals, or between multiple
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* pending non-realtime signals, is unspecified.
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*
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* Input Parameters:
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* set - The set of pending signals to wait for
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* sig - The location in which to store the pending signal number.
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*
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* Returned Value:
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* Upon successful completion, sigwait() stores the signal number of the
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* received signal at the location referenced by sig and returns zero.
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* Otherwise, an error number is returned to indicate the error.
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*
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****************************************************************************/
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int sigwait(FAR const sigset_t *set, FAR int *sig)
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{
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int signo;
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DEBUGASSERT(set != NULL && sig != NULL);
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/* The standard sigwait() function behaves that same as sigwaitinfo() with
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* the info argument set to NULL.
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*/
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signo = sigwaitinfo(set, NULL);
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if (signo < 0)
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{
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/* If sigwaitinfo() fails, return the error number */
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return get_errno();
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}
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/* Return the signal number in the user provided location */
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*sig = signo;
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return OK;
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}
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