Message Queues API Changes

Owned by Former user (Deleted)
Last updated: Mar 23, 2021 by WES Admin
3 min read

This table shows the difference in API for message-queue management.

Message Queues API
µC/OS-II (os_q.c)µC/OS-III (os_q.c)Note
void * 
 OSQAccept( 
     OS_EVENT  *pevent, 
     INT8U     *perr);

(1)
OS_EVENT * 
 OSQCreate( 
     void     **start, 
     INT16U     size);
void 
 OSQCreate( 
     OS_Q         *p_q, 
     CPU_CHAR     *p_name, 
     OS_MSG_QTY    max_qty, 
     OS_ERR       *p_err);
(2)
OS_EVENT * 
 OSQDel( 
     OS_EVENT  *pevent, 
     INT8U      opt, 
     INT8U     *perr);
OS_OBJ_QTY, 
 OSQDel( 
     OS_Q         *p_q, 
     OS_OPT        opt, 
     OS_ERR       *p_err);

INT8U 
 OSQFlush( 
     OS_EVENT  *pevent);
OS_MSG_QTY 
 OSQFlush( 
     OS_Q         *p_q, 
     OS_ERR       *p_err);

void * 
 OSQPend( 
     OS_EVENT  *pevent, 
     INT32U     timeout, 
     INT8U     *perr);
void * 
 OSQPend( 
     OS_Q         *p_q, 
     OS_MSG_SIZE  *p_msg_size, 
     OS_TICK       timeout, 
     OS_OPT        opt,  
     CPU_TS       *p_ts, 
     OS_ERR       *p_err);
(3)
INT8U 
 OSQPendAbort( 
     OS_EVENT  *pevent, 
     INT8U      opt, 
     INT8U     *perr);
OS_OBJ_QTY 
 OSQPendAbort( 
     OS_Q         *p_q, 
     OS_OPT        opt, 
     OS_ERR       *p_err);

INT8U 
 OSQPost( 
     OS_EVENT  *pevent, 
     void      *pmsg);
void 
 OSQPost( 
     OS_Q         *p_q, 
     void         *p_void, 
     OS_MSG_SIZE   msg_size, 
     OS_OPT        opt, 
     OS_ERR       *p_err);
(4)
INT8U 
 OSQPostFront( 
     OS_EVENT  *pevent, 
     void      *pmsg);


INT8U 
 OSQPostOpt( 
     OS_EVENT  *pevent, 
     void      *pmsg, 
     INT8U      opt);

(4)
INT8U 
 OSQQuery( 
     OS_EVENT  *pevent, 
     OS_Q_DATA *p_q_data);

(5)

(1) In µC/OS-III, there is no “accept” API as this feature is built into the OSQPend() by specifying the OS_OPT_PEND_NON_BLOCKING option.

(2) In µC/OS-II, OSQCreate() returns the address of an OS_EVENT, which is used as the “handle” to the message queue. In µC/OS-III, the application must allocate storage for an OS_Q object, which serves the same purpose as the OS_EVENT. The benefit in µC/OS-III is that it is not necessary to predetermine at compile time, the number of message queues.

(3) µC/OS-III returns additional information when a message queue is posted. Specifically, the sender includes the size of the message and takes a snapshot of the current timestamp and stores it in the message. The receiver of the message therefore knows when the message was posted.

(4) In µC/OS-III, OSQPost() offers a number of options that replaces the three post functions provided in µC/OS-II.

(5) µC/OS-III does not provide query services as they were rarely used.