Does QWaitCondition::wait locks the mutex again?

[HenryGer]

Accroding to doc
the QWaitCondition::wait unlocks the mutex, but in the same doc there is example

forever {
    mutex.lock();
    keyPressed.wait(&mutex);
    do_something();
    mutex.unlock();
}

in the last line the mutex is unlocked again. Why?? Does QWaitCondition::wait locks it again?

[fmedlin]

Yes, it does. In the docs for QWaitCondition::wait()

The lockedMutex will be returned to the same locked state. This function is provided to allow the atomic transition from the locked state to the wait state.