one signal need to be sampled and analyzed after. What I want is creating a queue then put all samples into it. During sampling, no data processing task can read the queue. On the other hand, when data processing is on going, no task can write to the queue. How can I create a guarded queue for this purpose? other suggestions? Thanks.

Sounds like you don't need a queue at all and would be better off just placing the data in an array.

Thank you, you light my way.