al_get_event_source_data - Allegro 5 API

       Returns  the abstract user data associated with the event source.  If no data was previously set, returns
       NULL.

       al_get_event_source_data - Allegro 5 API

al_set_event_source_data(3alleg5)

Allegro reference manual                                                       al_get_event_source_data(3alleg5)

              #include <allegro5/allegro.h>

              intptr_t al_get_event_source_data(const ALLEGRO_EVENT_SOURCE *source)