incubator-nuttx/include/nuttx/mqueue.h

207 lines
7.1 KiB
C

/****************************************************************************
* include/nuttx/mqueue.h
*
* Copyright (C) 2007, 2009, 2011, 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
#ifndef ___INCLUDE_NUTTX_MQUEUE_H
#define ___INCLUDE_NUTTX_MQUEUE_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/compiler.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <mqueue.h>
#include <queue.h>
#include <signal.h>
#if CONFIG_MQ_MAXMSGSIZE > 0
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Global Type Declarations
****************************************************************************/
/* This structure defines a message queue */
struct mq_des; /* forward reference */
struct mqueue_inode_s
{
FAR struct inode *inode; /* Containing inode */
sq_queue_t msglist; /* Prioritized message list */
int16_t maxmsgs; /* Maximum number of messages in the queue */
int16_t nmsgs; /* Number of message in the queue */
int16_t nwaitnotfull; /* Number tasks waiting for not full */
int16_t nwaitnotempty; /* Number tasks waiting for not empty */
#if CONFIG_MQ_MAXMSGSIZE < 256
uint8_t maxmsgsize; /* Max size of message in message queue */
#else
uint16_t maxmsgsize; /* Max size of message in message queue */
#endif
#ifndef CONFIG_DISABLE_SIGNALS
FAR struct mq_des *ntmqdes; /* Notification: Owning mqdes (NULL if none) */
pid_t ntpid; /* Notification: Receiving Task's PID */
int ntsigno; /* Notification: Signal number */
union sigval ntvalue; /* Notification: Signal value */
#endif
};
/* This describes the message queue descriptor that is held in the
* task's TCB
*/
struct mq_des
{
FAR struct mq_des *flink; /* Forward link to next message descriptor */
FAR struct mqueue_inode_s *msgq; /* Pointer to associated message queue */
int oflags; /* Flags set when message queue was opened */
};
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Global Function Prototypes
****************************************************************************/
#ifdef __cplusplus
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif
/************************************************************************
* Name: mq_msgqfree
*
* Description:
* This function deallocates an initialized message queue structure.
* First, it deallocates all of the queued messages in the message
* queue. It is assumed that this message is fully unlinked and
* closed so that no thread will attempt access it while it is being
* deleted.
*
* Inputs:
* msgq - Named essage queue to be freed
*
* Return Value:
* None
*
************************************************************************/
void mq_msgqfree(FAR struct mqueue_inode_s *msgq);
/****************************************************************************
* Name: mq_msgqalloc
*
* Description:
* This function implements a part of the POSIX message queue open logic.
* It allocates and initializes a structu mqueue_inode_s structure.
*
* Parameters:
* mode - mode_t value is ignored
* attr - The mq_maxmsg attribute is used at the time that the message
* queue is created to determine the maximum number of
* messages that may be placed in the message queue.
*
* Return Value:
* The allocated and initalized message queue structure or NULL in the
* event of a failure.
*
****************************************************************************/
struct mq_attr;
FAR struct mqueue_inode_s *mq_msgqalloc(mode_t mode,
FAR struct mq_attr *attr);
/****************************************************************************
* Name: mq_descreate
*
* Description:
* Create a message queue descriptor for the specified TCB
*
* Inputs:
* TCB - task that needs the descriptor.
* msgq - Named message queue containing the message
* oflags - access rights for the descriptor
*
* Return Value:
* On success, the message queue descriptor is returned. NULL is returned
* on a failure to allocate.
*
****************************************************************************/
struct tcb_s;
mqd_t mq_descreate(FAR struct tcb_s* mtcb, FAR struct mqueue_inode_s* msgq,
int oflags);
/****************************************************************************
* Name: mq_desclose
*
* Description:
* This function performs the portion of the mq_close operation related
* to freeing resource used by the message queue descriptor itself.
*
* Parameters:
* mqdes - Message queue descriptor.
*
* Return Value:
* None
*
* Assumptions:
* - Called only from mq_close() with the scheduler locked.
*
****************************************************************************/
void mq_desclose(mqd_t mqdes);
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* CONFIG_MQ_MAXMSGSIZE > 0 */
#endif /* ___INCLUDE_NUTTX_MQUEUE_H */