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undefined reference to '_xQueueCreateMutex'

Posted by ady001 on April 28, 2016

Dear Support, I've been evaluating the RTOS on the PIC24 platform and have been impressed. I've got tasks with priorities, messages queues, critical sections etc.

I wanted to have a play with a Mutex but the linker does not seem to like xSemaphoreCreateMutex() even though it is happy with my later use of xSemaphoreGive() and xSemaphoreTake() in the same file. Maybe I've missed a header file or a defintion somewhere but I'm stuck.

/* My includes */ include "FreeRTOS.h" include "task.h" include "semphr.h" include "queue.h"

/* My Mutex handle */ static SemaphoreHandlet MutexHandleAppTestLED = NULL;

/* My Mutex creation */ void vApplicationMutex(void) { MutexHandle_AppTestLED = xSemaphoreCreateMutex(); }

// Error thrown by the linker... : In function _vApplicationMutex': : undefined reference toxQueueCreateMutex' build/default/production/ext/1472/ApplicationTask.o(.text+0x12): In function _vApplicationMutex': : undefined reference to_xQueueCreateMutex'

The function xSemaphoreCreateMutex() is in blue in the project, showing it is recognize as a function and 'Navigate to defintion' opens the file semphr.h at the extract below ( where the section is active in the compilation ).

if( configSUPPORTDYNAMICALLOCATION == 1 ) define xSemaphoreCreateMutex() xQueueCreateMutex( queueQUEUETYPEMUTEX ) endif

Please can you help ?

Kind regards, Ady

undefined reference to '_xQueueCreateMutex'

Posted by davedoors on April 28, 2016

Is configUSE_MUTEXES set to 1 in FreeRTOSConfig.h?

undefined reference to '_xQueueCreateMutex'

Posted by ady001 on April 28, 2016

Many thanks that has solved it. In fact configUSE_MUTEXES was not in FreeRTOSConfig.h at all else I would have given it a try ! I'd expect all configurable options to be in this file ?

undefined reference to '_xQueueCreateMutex'

Posted by rtel on April 28, 2016

That is quite an old demo, perhaps even created before there were mutexes? http://www.freertos.org/a00110.html

undefined reference to '_xQueueCreateMutex'

Posted by ady001 on April 28, 2016

OK fair enough. I used the demo to get up and running, I'll look for the latest FreeRTOS source.

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