Just as binary semaphores can be thought of as queues of length one, counting semaphores can be thought of as queues of length greater than one. Again, users of the semaphore are not interested in the data that is stored in the queue - just whether or not the queue is empty or not.
Counting semaphores are typically used for two things:
See the Semaphores/Mutexes section of the user documentation for a list of semaphore related API functions. Searching the files in the FreeRTOS/Demo/Common/Minimal directory will reveal multiple examples of their usage. Note that interrupts must NOT use API functions that do not end in "FromISR".
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