236 lines
8.2 KiB
C
236 lines
8.2 KiB
C
/****************************************************************************
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* sched/mqueue/mq_open.c
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*
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* Copyright (C) 2007-2009, 2011 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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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 <sys/types.h>
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#include <stdint.h>
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#include <stdarg.h>
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#include <mqueue.h>
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#include <fcntl.h>
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#include <string.h>
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#include <sched.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/kmalloc.h>
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#include "sched/sched.h"
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#include "mqueue/mqueue.h"
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/****************************************************************************
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* Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Type Declarations
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****************************************************************************/
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/****************************************************************************
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* Global Variables
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****************************************************************************/
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/****************************************************************************
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* Private Variables
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: mq_open
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*
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* Description:
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* This function establish a connection between a named message queue and
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* the calling task. After a successful call of mq_open(), the task can
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* reference the message queue using the address returned by the call. The
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* message queue remains usable until it is closed by a successful call to
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* mq_close().
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*
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* Parameters:
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* mq_name - Name of the queue to open
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* oflags - open flags
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* Optional parameters. When the O_CREAT flag is specified, two optional
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* parameters are expected:
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*
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* 1. mode_t mode (ignored), and
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* 2. struct mq_attr *attr. The mq_maxmsg attribute
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* is used at the time that the message queue is
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* created to determine the maximum number of
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* messages that may be placed in the message queue.
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*
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* Return Value:
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* A message queue descriptor or -1 (ERROR)
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*
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* Assumptions:
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*
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****************************************************************************/
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mqd_t mq_open(const char *mq_name, int oflags, ...)
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{
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FAR struct tcb_s *rtcb = (FAR struct tcb_s*)g_readytorun.head;
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FAR msgq_t *msgq;
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mqd_t mqdes = NULL;
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va_list arg; /* Points to each un-named argument */
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struct mq_attr *attr; /* MQ creation attributes */
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int namelen; /* Length of MQ name */
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/* Make sure that a non-NULL name is supplied */
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if (mq_name)
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{
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sched_lock();
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namelen = strlen(mq_name);
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if (namelen > 0)
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{
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/* See if the message queue already exists */
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msgq = mq_findnamed(mq_name);
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if (msgq)
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{
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/* It does. Check if the caller wanted to create a new
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* message queue with this name (i.e., O_CREAT|O_EXCL)
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*/
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if ((oflags & O_CREAT) == 0 || (oflags & O_EXCL) == 0)
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{
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/* Create a message queue descriptor for the TCB */
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mqdes = mq_descreate(rtcb, msgq, oflags);
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if (mqdes)
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{
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/* Allow a new connection to the message queue */
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msgq->nconnect++;
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}
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}
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}
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/* It doesn't exist. Should we create one? */
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else if ((oflags & O_CREAT) != 0)
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{
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/* Allocate memory for the new message queue. The size to
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* allocate is the size of the msgq_t header plus the size
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* of the message queue name+1.
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*/
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msgq = (FAR msgq_t*)kmm_zalloc(SIZEOF_MQ_HEADER + namelen + 1);
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if (msgq)
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{
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/* Create a message queue descriptor for the TCB */
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mqdes = mq_descreate(rtcb, msgq, oflags);
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if (mqdes)
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{
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/* Set up to get the optional arguments needed to create
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* a message queue.
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*/
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va_start(arg, oflags);
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(void)va_arg(arg, mode_t); /* MQ creation mode parameter (ignored) */
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attr = va_arg(arg, struct mq_attr*);
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/* Initialize the new named message queue */
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sq_init(&msgq->msglist);
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if (attr)
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{
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msgq->maxmsgs = (int16_t)attr->mq_maxmsg;
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if (attr->mq_msgsize <= MQ_MAX_BYTES)
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{
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msgq->maxmsgsize = (int16_t)attr->mq_msgsize;
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}
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else
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{
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msgq->maxmsgsize = MQ_MAX_BYTES;
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}
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}
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else
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{
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msgq->maxmsgs = MQ_MAX_MSGS;
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msgq->maxmsgsize = MQ_MAX_BYTES;
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}
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msgq->nconnect = 1;
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#ifndef CONFIG_DISABLE_SIGNALS
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msgq->ntpid = INVALID_PROCESS_ID;
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#endif
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strcpy(msgq->name, mq_name);
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/* Add the new message queue to the list of
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* message queues
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*/
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sq_addlast((FAR sq_entry_t*)msgq, &g_msgqueues);
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/* Clean-up variable argument stuff */
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va_end(arg);
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}
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else
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{
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/* Deallocate the msgq structure. Since it is
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* uninitialized, mq_deallocate() is not used.
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*/
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sched_kfree(msgq);
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}
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}
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}
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}
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sched_unlock();
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}
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if (mqdes == NULL)
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{
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return (mqd_t)ERROR;
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}
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else
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{
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return mqdes;
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}
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}
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