al_win_remove_window_callback - Man Page

#include <allegro5/allegro_windows.h>

bool al_win_remove_window_callback(ALLEGRO_DISPLAY *display,
   bool (*callback)(ALLEGRO_DISPLAY *display, UINT message, WPARAM wparam,
   LPARAM lparam, LRESULT *result, void *userdata), void *userdata)

Removes the callback that was previously registered with al_win_add_window_callback(3). The userdata pointer must be the same as what was used during the registration of the callback.

Returns true if the callback was removed.

5.1.2