Does the application GetMessage even during MessageBox?

Question

While handling WM_TIMER, I called MessageBox. As a result, a message box popped up with the frequency of the timer. So I believe that the application was tr

Answer 1

A modal dialog runs its own message loop internally, using the calling thread's message queue. You are calling MessageBox() inside your WM_TIMER handler, so the message loop inside of MessageBox() is receiving and dispatching subsequent WM_TIMER messages while the message box is running.