Quality RTOS & Embedded Software

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


When xSemphoareGive() pdFAIL

Posted by biosjimmy on January 23, 2018

I am a little confused on calling xSemaphoreGive returns pdFAIL.

In the FreeRTOS Reference Manual,

xSemaphoreGive( SemaphoreHandle_t xSemaphore );

Return Values:

pdFAIL: The semaphore ‘give’ operation was not successful because the task calling xSemaphoreGive() is not the semaphore holder.

Does this mean,

if the task calling xSemaphoreGive() is not the same task calling xSemaphoreTake(), xSemaphoreGive() returns pdFAIL?

When xSemphoareGive() pdFAIL

Posted by rtel on January 23, 2018

That is probably only right in the case of a mutex. Where is the text you are quoting found? pdf reference manual, online or in the book? I will check it, it might be wrong.

When xSemphoareGive() pdFAIL

Posted by biosjimmy on January 24, 2018

Thanks for the reply. This is what I thought too, mutex only.

The quoting is from the PDF version of The FreeRTOS™ Reference Manual.

[ 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.


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