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/**
* @file
*
* @brief Constants and Structures Associated with the Message Queue Handler.
*
* This include file contains all the constants and structures associated
* with the Message queue Handler.
*/
/*
* COPYRIGHT (c) 1989-2009.
* 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 _RTEMS_SCORE_COREMSG_H
#define _RTEMS_SCORE_COREMSG_H
#include <rtems/score/chain.h>
#include <rtems/score/isrlock.h>
#include <rtems/score/threadq.h>
#include <rtems/score/watchdog.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* @defgroup RTEMSScoreMessageQueue Message Queue Handler
*
* @ingroup RTEMSScore
*
* This handler encapsulates functionality which provides the foundation
* Message Queue services used in all of the APIs supported by RTEMS.
*/
/**@{*/
/**
* This macro is defined when an API is enabled that requires that the
* Message Queue Handler include support for priority based enqueuing
* of messages.
*/
#define RTEMS_SCORE_COREMSG_ENABLE_MESSAGE_PRIORITY
#if defined(RTEMS_POSIX_API)
/**
* This macro is defined when an API is enabled that requires that the
* Message Queue Handler include support for notification of enqueuing
* a message.
*/
#define RTEMS_SCORE_COREMSG_ENABLE_NOTIFICATION
#endif
/**
* This macro is defined when an API is enabled that requires the
* Message Queue Handler include support for blocking send operations.
*/
#define RTEMS_SCORE_COREMSG_ENABLE_BLOCKING_SEND
typedef struct CORE_message_queue_Control CORE_message_queue_Control;
/**
* @brief Data types needed to manipulate the contents of message buffers.
*
* The following defines the data types needed to manipulate
* the contents of message buffers.
*
* @note The buffer field is normally longer than a single uint32_t
* but since messages are variable length we just make a ptr to 1.
*/
typedef struct {
/** This field is the size of this message. */
size_t size;
/** This field contains the actual message. */
uint32_t buffer[1];
} CORE_message_queue_Buffer;
/**
* @brief The organization of a message buffer.
*
* The following records define the organization of a message
* buffer.
*/
typedef struct {
/** This element allows this structure to be placed on chains. */
Chain_Node Node;
#if defined(RTEMS_SCORE_COREMSG_ENABLE_MESSAGE_PRIORITY)
/** This field is the priority of this message. */
int priority;
#endif
/** This field points to the contents of the message. */
CORE_message_queue_Buffer Contents;
} CORE_message_queue_Buffer_control;
/**
* @brief The possible blocking disciplines for a message queue.
*
* This enumerated types defines the possible blocking disciplines
* for a message queue.
*/
typedef enum {
/** This value indicates that blocking tasks are in FIFO order. */
CORE_MESSAGE_QUEUE_DISCIPLINES_FIFO,
/** This value indicates that blocking tasks are in priority order. */
CORE_MESSAGE_QUEUE_DISCIPLINES_PRIORITY
} CORE_message_queue_Disciplines;
#if defined(RTEMS_SCORE_COREMSG_ENABLE_NOTIFICATION)
/**
* @brief Type for a notification handler.
*
* The following defines the type for a Notification handler. A
* notification handler is invoked when the message queue makes a
* 0->1 transition on pending messages.
*/
typedef void (*CORE_message_queue_Notify_Handler)(
CORE_message_queue_Control *,
Thread_queue_Context *
);
#endif
/**
* @brief Control block used to manage each message queue.
*
* The following defines the control block used to manage each
* Message Queue.
*/
struct CORE_message_queue_Control {
/** This field is the Waiting Queue used to manage the set of tasks
* which are blocked waiting to receive a message from this queue.
*/
Thread_queue_Control Wait_queue;
/**
* @brief The thread queue operations according to the blocking discipline.
*/
const Thread_queue_Operations *operations;
/** This element is maximum number of messages which may be pending
* at any given time.
*/
uint32_t maximum_pending_messages;
/** This element is the number of messages which are currently pending.
*/
uint32_t number_of_pending_messages;
/** This is the size in bytes of the largest message which may be
* sent via this queue.
*/
size_t maximum_message_size;
/** This chain is the set of pending messages. It may be ordered by
* message priority or in FIFO order.
*/
Chain_Control Pending_messages;
/** This is the address of the memory allocated for message buffers.
* It is allocated are part of message queue initialization and freed
* as part of destroying it.
*/
CORE_message_queue_Buffer *message_buffers;
#if defined(RTEMS_SCORE_COREMSG_ENABLE_NOTIFICATION)
/** This is the routine invoked when the message queue transitions
* from zero (0) messages pending to one (1) message pending.
*/
CORE_message_queue_Notify_Handler notify_handler;
#endif
/** This chain is the set of inactive messages. A message is inactive
* when it does not contain a pending message.
*/
Chain_Control Inactive_messages;
};
/**@}*/
#ifdef __cplusplus
}
#endif
#endif
/* end of include file */
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