Flying over Qt multithreading technologies

Built upon QThread, several threading technologies are available in Qt. First, to synchronize threads, the usual approach is to use a mutual exclusion (mutex) that will apply for a given resource. Qt provides it by means of the QMutex class. Its usage is straightforward:

QMutex mutex; 
int number = 1; 
 
mutex.lock(); 
number *= 2; 
mutex.unlock(); 

From the mutex.lock() instruction, any other thread trying to lock mutex will wait until mutex.unlock() has been called.

The locking/unlocking mechanism is error-prone in complex code. You can easily forget to unlock a mutex in a specific exit condition, causing a deadlock. To simplify this situation, Qt provides QMutexLocker, which should be used where QMutex ...

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