Waiting for the Condition

To use condition variables, follow these steps in the code path waiting for the condition:

1. Acquire the mutex guarding the condition.

2. Test the condition.

3. If the test results do not allow the thread to continue, use cv_wait(9F) to block the current thread on the condition. cv_wait(9F) releases the mutex before blocking. Upon return from cv_wait(9F) (which will reacquire the mutex before returning), repeat the test.

4. Once the test allows the thread to continue, set the condition to its new value. For example, set a device flag to busy.

5. Release the mutex.