creating task inside other task in freertos

Question

I am an RTOS newbie and I am creating a simple real time system for automotive

I am wondering if it possible to create a task inside another task. I tried to do this by the following method but it doesn't work.

 void vTask1 { *pvParameters){
unsigned portBASE_TYPE taskPriority;
taskPriority=uxTaskPriorityGet( NULL );
char x;
while (1){
 x= 5 ;
if (x==5)
xTaskCreate( vTask2 , "task2", 1000, "task2 is running", taskPriority+5 , NULL );
}

when I debug that code it hangs at xTaskCreate without executing the new task and I searched the manual and the internet for something about this but I didn't find any.

would anyone tell me is that possible to do in RTOS or I am doing it in a wrong way?

Try creating the task outside of the while loop. xTaskCreate(...); while(1); If you get to the while(1), then your scheduler isn't switching tasks or you haven't created the task properly. — Ross
What is the response code you're getting from the xTaskCreate() call? If it's not pdPASS the task is not being created. — Ross
@Ross XTaskCreate() is not giving me pdPASS unfortunately , what are the possible reasons in your opinion? — Jay Shenawy
I want to note that I am using xTaskCreate in a more complicated code. The code I wrote upwards was just a simple example for what I am doing — Jay Shenawy

Richard Richard · Accepted Answer · 2014-08-08T05:36:50

Tasks can be created before the scheduler has been started (from main), or after the scheduler has been started (from another task). The xTaskCreate() API documentation is here: http://www.freertos.org/a00125.html . You will also find a set of demo tasks that demonstrate creating and deleting tasks from another task in the main FreeRTOS .zip file download. Look in the FreeRTOS/Demo/Common/Minimal/death.c file (death for suicidal tasks as they delete themselves after creation).

If xTaskCreate() returns NULL then you will probably have run out of heap space. See http://www.freertos.org/a00111.html. I think most of the hundreds or pre-configured examples that come in the zip file download have comments to this effect.

creating task inside other task in freertos

2 Answers