Game Programming using Qt 5 Beginner's Guide - Second Edition

Time for action – Functionality of a tic-tac-toe board

We need to implement a function that will be called upon by clicking on any of the nine buttons on the board. It has to change the text of the button that was clicked on—either "X" or "O"—based on which player made the move. It then has to check whether the move resulted in the game being won by the player (or a draw if no more moves are possible), and if the game ended, it should emit an appropriate signal, informing the environment about the event.

When the user clicks on a button, the clicked() signal is emitted. Connecting this signal to a custom slot lets us implement the mentioned functionality, but since the signal doesn't carry any parameters, how do we tell which button caused ...