Описание тега qtimer
QTimer is a timer class provided by the cross-platform Qt framework.
The QTimer class provides repetitive and single-shot timers.
The QTimer class provides a high-level programming interface for timers. To use it, create a QTimer, connect its timeout() signal to the appropriate slots, and call start(). From then on it will emit the timeout() signal at constant intervals.
The official Qt documentation can be found here for Qt 4.8 and here for Qt 5.