_task_create() returns null

[VinceTF]

Device: mcf52258

MQX version: 3.8.1

Compilier: CW Eclipse 10.2

My application has 15 tasks.  For about a year all the tasks have been getting created without any issues that I can observe.

For no reason that I can see, the last task to be created is returning 0 when _task_create() is called.  I verified thread priorities, and there are no duplicates.

What can I do to determine why the last task is not getting created?

-Vince

[BielikM]

Hi Vincent,

Maybe you doesn't have enough stack for creating tasks. Try to check TAD (task aware debugging) in cw10.2 IDE or try to made stacks of your tasks smaller.

Regards,

Martin

[VinceTF]

_task_get_error() returned code 4 which is MQX_OUT_OF_MEMORY.  I reduced the size of the stack for the task that was returning the error and everything works now.

Thanks to both of you for your quick response and your help.  I feel both of your responses are correct, but the forum only allows one to be selected as correct.

[c0170]

Hello Vincent Gagliardo,

please look at the code in mqx/source/kernel/task.c where it's _task_create_internal function. This one is invoked inside _task_create.

You'll see all possible returns with MQX_NULL_TASK_ID.

Snippet from MQX reference manual:

Traits

• If the child is on another processor, blocks the creator until the child is created

• On failure, calls _task_set_error() to set the task error code (see task error codes)

• For _task_create():

— If the child is on the same processor, preempts the creator if the child is a higher priority

Have you checked task error code ? Once you solve your problem, share it with the community. ThX.

Regards,

c0170