/**
* @file
*
* @brief POSIX Message Queues
*
* This file contains the definitions related to POSIX Message Queues.
*
* The structure of the routines is identical to that of POSIX
* Message_queues to leave the option of having unnamed message
* queues at a future date. They are currently not part of the
* POSIX standard but unnamed message_queues are. This is also
* the reason for the apparently unnecessary tracking of
* the process_shared attribute. [In addition to the fact that
* it would be trivial to add pshared to the mq_attr structure
* and have process private message queues.]
*
* This code ignores the O_RDONLY/O_WRONLY/O_RDWR flag at open
* time.
*/
/*
* COPYRIGHT (c) 1989-2011.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#ifndef _MQUEUE_H
#define _MQUEUE_H
#include <unistd.h>
#if defined(_POSIX_MESSAGE_PASSING)
#include <sys/types.h>
#include <rtems/system.h>
#include <rtems/score/object.h>
/**
* @defgroup POSIX_MQUEUE POSIX Message Queues
*
* @ingroup POSIXAPI
*
*/
/**@{**/
#ifdef __cplusplus
extern "C" {
#endif
/*
* 15.1.1 Data Structures, P1003.1b-1993, p. 271
*/
/**
* Message queue id type.
*
* NOTE: Use uint32_t since all POSIX Ids are 32-bit currently.
*/
typedef uint32_t mqd_t;
/**
* This is the message queue attributes structure.
*/
struct mq_attr {
/** This is the message queue flags */
long mq_flags;
/** This is the maximum number of messages */
long mq_maxmsg;
/** This is the maximum message size */
long mq_msgsize;
/** This is the mumber of messages currently queued */
long mq_curmsgs;
};
/**
* 15.2.2 Open a Message Queue, P1003.1b-1993, p. 272
*/
mqd_t mq_open(
const char *name,
int oflag,
...
);
/**
* 15.2.2 Close a Message Queue, P1003.1b-1993, p. 275
*/
int mq_close(
mqd_t mqdes
);
/**
* @brief Remove a message queue.
*
* 15.2.2 Remove a Message Queue, P1003.1b-1993, p. 276
*
* NOTE: The structure of the routines is identical to that of POSIX
* Message_queues to leave the option of having unnamed message
* queues at a future date. They are currently not part of the
* POSIX standard but unnamed message_queues are. This is also
* the reason for the apparently unnecessary tracking of
* the process_shared attribute. [In addition to the fact that
* it would be trivial to add pshared to the mq_attr structure
* and have process private message queues.]
*
* This code ignores the O_RDONLY/O_WRONLY/O_RDWR flag at open
* time.
*/
int mq_unlink(
const char *name
);
/**
* 15.2.4 Send a Message to a Message Queue, P1003.1b-1993, p. 277
*
* NOTE; P1003.4b/D8, p. 45 adds mq_timedsend().
*/
int mq_send(
mqd_t mqdes,
const char *msg_ptr,
size_t msg_len,
unsigned int msg_prio
);
#if defined(_POSIX_TIMEOUTS)
#include <time.h>
/**
* @brief Send a message to a message queue.
*
* @see mq_send()
*/
int mq_timedsend(
mqd_t mqdes,
const char *msg_ptr,
size_t msg_len,
unsigned int msg_prio,
const struct timespec *abstime
);
#endif /* _POSIX_TIMEOUTS */
/**
* @brief Receive a message from a message queue.
*
* 15.2.5 Receive a Message From a Message Queue, P1003.1b-1993, p. 279
*
* NOTE: P1003.4b/D8, p. 45 adds mq_timedreceive().
*/
ssize_t mq_receive(
mqd_t mqdes,
char *msg_ptr,
size_t msg_len,
unsigned int *msg_prio
);
#if defined(_POSIX_TIMEOUTS)
ssize_t mq_timedreceive(
mqd_t mqdes,
char *__restrict msg_ptr,
size_t msg_len,
unsigned int *__restrict msg_prio,
const struct timespec *__restrict abstime
);
#endif /* _POSIX_TIMEOUTS */
#if defined(_POSIX_REALTIME_SIGNALS)
/**
* @brief Notify process that a message is available on a queue.
*
* 15.2.6 Notify Process that a Message is Available on a Queue,
* P1003.1b-1993, p. 280
*/
int mq_notify(
mqd_t mqdes,
const struct sigevent *notification
);
#endif /* _POSIX_REALTIME_SIGNALS */
/**
* @brief Set message queue attributes.
*
* 15.2.7 Set Message Queue Attributes, P1003.1b-1993, p. 281
*/
int mq_setattr(
mqd_t mqdes,
const struct mq_attr *__restrict mqstat,
struct mq_attr *__restrict omqstat
);
/*
* 15.2.8 Get Message Queue Attributes, P1003.1b-1993, p. 283
*/
int mq_getattr(
mqd_t mqdes,
struct mq_attr *mqstat
);
/** @} */
#ifdef __cplusplus
}
#endif
#endif /* _POSIX_MESSAGE_PASSING */
#endif
/* end of include file */