Store events in queue

savindra wrote on Friday, November 04, 2016:

Hello ,

I have created a queue to store 10 events and i want to display those events on LCD.

I do not want to remove the event from queue once i receive event from queue .
Event will be removed only when queue is full and a new event comes.

I am facing a problem while looping over the events from queue. Only front event is displaying on LCD.
Please tell me how can i give pointer to next event in Queue.
and Is there any function in FreeRTOS if queue is full then remove the front event in queue and make space or next event?

Below is my code :

    Type_ErrorEvent ErrEvent;
     uint8_t ucNoOfMsg;
     uint8_t ucCount;
	  ucNoOfMsg = uxQueueMessagesWaiting( xQueue );
	  for( ucCount = 0; ucCount < ucNoOfMsg ;ucCount++)
		  if( xQueuePeek( xQueue , &ErrEvent, ( TickType_t ) 2  ) )
			  SCR_SetTextAtXY(ErrEvent.sTimeStamp, 1, ucCount + 2);
			  SCR_SetTextAtXY(ErrEvent.sComment, 21, ucCount + 2);	

richard_damon wrote on Friday, November 04, 2016:

QueuePeek only returns the event at the front of the queue, so that won’t work for your application.

It sounds like you don’t really want a queue, but just an array in memory, guarded by a mutex or the like for updates, with a list of the last 10 events. The big thing the queue provides is blocking when queue is full/empty which sounds like you do not want.