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[FreeRTOS Home] [Live FreeRTOS Forum] [FAQ] [Archive Top] [February 2007 Threads] Problems with passing parameters to taskPosted by dennis on February 7, 2007 Hi,
I'm experiencing a strange problem in passing parameters to a simple task of toggling an led. Below is my code:
//================================================================================= const unsigned long SLEEP_TIME[] = {1000000, 3000000}; //sleep for 1 and 3 sec.
void tskFlashLED( void * ptr ) { unsigned int index = *((unsigned int*)ptr); //index of led for(;;){ if(index < 2){ vTaskDelay( (unsigned long)SLEEP_TIME[index]/(1000*portTICK_RATE_MS) ); //Delay for 1 or 3 sec if(led_status(index) == 0){ led_on(index);//Turn on led } else{ led_off(index);//Turn off led } } } }
void vUserMain(){ unsigned int arg1 = 0;//Index xTaskCreate(tskFlashLED, NULL, configMINIMAL_STACK_SIZE, &arg1, tskIDLE_PRIORITY, NULL); } //=================================================================================
After debugging, I've found that the value of index not equals to arg1 (i.e. 0). Can anyone suggest what might be the problem? My port is dsPic30f5011
Many thanks!
Dennis
RE: Problems with passing parameters to taskPosted by Richard on February 7, 2007 You are passing the address of a variable that is allocated on the stack of a function - and therefore is only temporary.
Regards.
RE: Problems with passing parameters to taskPosted by dennis on February 8, 2007 Hi Richand,
Thank you very much for your prompt reply.
What can I do to work round the problem? In fact, I've already taken reference to the example code on BlockQ.c, and I've already saved a copy of the value when I enter the function as follow:
void tskFlashLED( void * ptr ) { unsigned int index = *((unsigned int*)ptr); //index of led ... }
Thank you in advance.
Dennis
RE: Problems with passing parameters to taskPosted by dennis on February 8, 2007 Hi!
I've just figured out how to solve the problem.
Since $arg1 is reside in the function vUserMain(), on exit of the function, the local variable $arg1 will not be valid anymore. So $arg1 should either be global of declared static (as in dynamic.c).
Many thanks for your attention.
Dennis
RE: Problems with passing parameters to taskPosted by raedbenz on November 30, 2009 hi, is this allowed?
(hash)define LED1 0x0020
xTaskCreate(tskFlashLED, NULL, configMINIMAL_STACK_SIZE, (void*)LED1 , tskIDLE_PRIORITY, NULL);
i get this " invalid lvalue in unary '&' " Plz how can I get around this? use an defined value as an argument?
RE: Problems with passing parameters to taskPosted by raedbenz on December 1, 2009 sorry, last post sorted..thanks
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