What are the functions of the pushbuttons on a chronograph?

The push buttons serve to start or stop the function and to reset the chronograph. Usually, the push button at 2 o'clock is to start and stop the chronograph function. The 4 o'clock button is to reset as well as to measure the split time. 

1. The 2 o'clock push-button to start the chronograph.
2. The 4 o'clock push-button to read the intermediary time.
3. Once again to continue (repeat the last two actions as many times as you wish to read the intermediary time while the chrono carries on).
4. The 2 o'clock push-button to stop finally.
5. The 4 o'clock push-button to reset.