Quality RTOS & Embedded Software

 Real time embedded FreeRTOS RSS feed 
Quick Start Supported MCUs PDF Books Trace Tools Ecosystem


Loading

how to empty the queue??

Posted by Nobody/Anonymous on February 15, 2007

Hi all,

I need to empty the queue at certain places in my code.

The only way I can find is reading from queue untill it is empty. But this is not an efficeint method as reading is implemented as a memory copy, and it is wasting time reading all queue data just to throw away.

Is there a function which will just adjust the pointers of queue as it is empty?

I need a very fast queue empty mechanism.

Thanks.

RE: how to empty the queue??

Posted by embeddedc on February 15, 2007
You can add the following function to queue.c

void vQueueEmpty( xQueueHandle pxQueue )
{
pxNewQueue->uxMessagesWaiting = 0;
pxNewQueue->pcWriteTo = pxNewQueue->pcHead;
pxNewQueue->pcReadFrom = pxNewQueue->pcHead + ( ( uxQueueLength - 1 ) * uxItemSize );
pxNewQueue->xRxLock = queueUNLOCKED;
pxNewQueue->xTxLock = queueUNLOCKED;
vListInitialise( &( pxNewQueue->xTasksWaitingToSend ) );
vListInitialise( &( pxNewQueue->xTasksWaitingToReceive ) );
}

Be vary careful not to call it when there are tasks blocked on the queue!

RE: how to empty the queue??

Posted by Nobody/Anonymous on February 16, 2007

Hi,

Thank you for your help.

My need involves the need to empty queue even when some tasks are waiting on the queue.

Is there any way to do that??

I will try to use the funtion you provided and modify it according to my need, But it will be good if I get a tested function.

Thanks


[ Back to the top ]    [ About FreeRTOS ]    [ Privacy ]    [ Sitemap ]    [ ]


Copyright (C) Amazon Web Services, Inc. or its affiliates. All rights reserved.

Latest News

NXP tweet showing LPC5500 (ARMv8-M Cortex-M33) running FreeRTOS.

Meet Richard Barry and learn about running FreeRTOS on RISC-V at FOSDEM 2019

Version 10.1.1 of the FreeRTOS kernel is available for immediate download. MIT licensed.

View a recording of the "OTA Update Security and Reliability" webinar, presented by TI and AWS.


Careers

FreeRTOS and other embedded software careers at AWS.



FreeRTOS Partners

ARM Connected RTOS partner for all ARM microcontroller cores

Espressif ESP32

IAR Partner

Microchip Premier RTOS Partner

RTOS partner of NXP for all NXP ARM microcontrollers

Renesas

STMicro RTOS partner supporting ARM7, ARM Cortex-M3, ARM Cortex-M4 and ARM Cortex-M0

Texas Instruments MCU Developer Network RTOS partner for ARM and MSP430 microcontrollers

OpenRTOS and SafeRTOS

Xilinx Microblaze and Zynq partner