Quality RTOS & Embedded Software

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



Posted by burry94 on May 25, 2017

Hi! We would like to modify the value of the system variable pxMutexHolder defined in the file task.c, how can we access its value through a function? We tried to change its value from our main() but it didn't work since pxMutexHoder cannot be accessed by our application.


Posted by rtel on May 25, 2017

I don't think pxMutexHolder is a system variable defined inside tasks.c. The function xTaskPriorityInherit() has a parameter called pxMutexHolder - is that what you mean? That parameter is local to the function xTaskPriorityInherit() so can't be changed. The mutex holder value is actually stored inside a queue structure, which is defined in queue.c, not a task control block. You could potentially change the value stored in the queue itself, that could be done using the traceBLOCKINGONQUEUE_RECEIVE() macro which gets executed (if defined) immediately before xTaskPriorityInherit() is called.

This is very detailed and messy though, and don't expect anything to work after you have modified it.

[ 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.

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.


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


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