UCOSII消息队列

主结构体

typedef struct os_q {              /* QUEUE CONTROL BLOCK */
    struct os_q   *OSQPtr;         /* Link to next queue control block in list of free blocks */
    void         **OSQStart;       /* Ptr to start of queue data */
    void         **OSQEnd;         /* Ptr to end of queue data */
    void         **OSQIn;          /* Ptr to where next message will be inserted in the Q */
    void         **OSQOut;         /* Ptr to where next message will be extracted from the Q */
    INT16U         OSQSize;        /* Size of queue (maximum number of entries) */
    INT16U         OSQEntries;     /* Current number of entries in the queue */
} OS_Q;

typedef struct os_q_data {
    void          *OSMsg;          /* Pointer to next message to be extracted from queue */
    INT16U         OSNMsgs;        /* Number of messages in message queue */
    INT16U         OSQSize;        /* Size of message queue */
    OS_PRIO        OSEventTbl[OS_EVENT_TBL_SIZE];  /* List of tasks waiting for event to occur */
    OS_PRIO        OSEventGrp;     /* Group corresponding to tasks waiting for event to occur */
} OS_Q_DATA;

typedef struct os_event {
    INT8U    OSEventType;          /* Type of event control block (see OS_EVENT_TYPE_xxxx) */
    void    *OSEventPtr;           /* Pointer to message or queue structure */
    INT16U   OSEventCnt;           /* Semaphore Count (not used if other EVENT type) */
    OS_PRIO  OSEventGrp;           /* Group corresponding to tasks waiting for event to occur */
    OS_PRIO  OSEventTbl[OS_EVENT_TBL_SIZE]; /* List of tasks waiting for event to occur */

#if OS_EVENT_NAME_EN > 0u
    INT8U   *OSEventName;
#endif
} OS_EVENT;

API函数

//无等待地从消息队列中得到一个消息
void *OSQAccept (OS_EVENT *pevent,
                 INT8U *perr);

//创建
OS_EVENT *OSQCreate (void **start,
                     INT16U size);

//删除
OS_EVENT *OSQDel (OS_EVENT *pevent,
                  INT8U opt,
                  INT8U *perr);

//清空
INT8U OSQFlush (OS_EVENT *pevent);

//等待-1，接收消息
void *OSQPend (OS_EVENT *pevent,
               INT32U timeout,
               INT8U *perr);

//取消等待
INT8U OSQPendAbort (OS_EVENT *pevent,
                    INT8U opt,
                    INT8U *perr);

//释放+1，发送消息（队列式）
INT8U OSQPost (OS_EVENT *pevent,
               void *pmsg);

//发送消息（堆栈式）
INT8U OSQPostFront (OS_EVENT *pevent,
                    void *pmsg);

//单选项的消息发送
INT8U OSQPostOpt (OS_EVENT *pevent,
                  void *pmsg,
                  INT8U opt);

//查询
INT8U OSQQuery (OS_EVENT *pevent,
                OS_Q_DATA *p_q_data);

应用举例

#define OSQ_MSG_NUM 1       //消息队列消息数量
OS_EVENT *DATA_Msg;
void *MsgGrp[OSQ_MSG_NUM];

void start_task(void *pdata)
{
    OS_CRITICAL_ENTER();    //进入临界区

    DATA_Msg = OSQCreate ((void**   )&MsgGrp[0],    
                         (INT16U )OSQ_MSG_NUM);

    OS_EXIT_CRITICAL();
}

void msgpost_task(void *p_arg)
{
    static u8 msg_num;
    OS_Q_DATA p_q_data;

    OSQQuery(DATA_Msg, &p_q_data);
    if(p_q_data.OSNMsgs >= OSQ_MSG_NUM)
    {
        printf("OSQQuery OSNMsgs: %d
", p_q_data.OSNMsgs);
        return;
    }

    msg_num++;
    OSQPost((OS_EVENT*  )DATA_Msg,      
            (void*      )&msg_num);
}

void msgpend_task(void *p_arg)
{
    void *p;
    INT8U err;
    u8 msg_num;

    p = OSQPend((OS_EVENT*  )DATA_Msg,   
                (INT32U     )0,
                (INT8U*     )&err);

    msg_num = *p;
}