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Cannot xQueueSend then crQUEUE_RECEIVE

Posted by Michael Carr on September 8, 2007
I just posted a bug that I couldn't add to a queue in a Task using xQueueSend and then retrieve from the queue in a coroutine using crQUEUE_RECEIVE. The reply to the bug was "This is not a bug. Unfortunately, tasks and co-routines cannot share a
queue or semaphore." If this is the case, I think the documentation should be modified to reflect this restriction, perhaps referring to "Task Queue" and "Coroutine Queue". Currently the documentation doesn't differentiate between Queue types.

RE: Cannot xQueueSend then crQUEUE_RECEIVE

Posted by Richard on September 8, 2007
I have to agree that the documentation was not as clear on this matter as it could be. I have added:

"Note that co-routines can only send data to other co-routines. A co-routine cannot use a queue to send data to a task or visa versa"

to the crSEND and crRECEIVE pages, and:

" Note that an application can be designed using just tasks, just co-routines, or a mixture of both - however tasks and co-routines use different API functions and therefore a queue (or semaphore) cannot be used to pass data from a task to a co-routine or visa versa."

to the page describing the differences between tasks and co-routines.


RE: Cannot xQueueSend then crQUEUE_RECEIVE

Posted by Michael Carr on September 8, 2007
Thank you, that clarifies the issue and will be helpful to others.

RE: Cannot xQueueSend then crQUEUE_RECEIVE

Posted by sashiono on September 12, 2007
I feel that it greatly reduces the functionality of co-routines that you cannot passed data between queues from a co-routine to a task. What causes it limitation and it there a way to connect the queues between the two?

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