nuttx/libs/libc/signal/sig_wait.c
Alin Jerpelea b5d4a01821 libs: Author Gregory Nutt: update licenses to Apache
Gregory Nutt has submitted the SGA and we can migrate the licenses
 to Apache.

Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
2021-03-03 18:52:53 -08:00

96 lines
3.9 KiB
C

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