mouse_callback - User specified mouse callback. Allegro game programming library.

       Called  by  the  interrupt  handler  whenever  the  mouse moves or one of the buttons changes state. This
       function must be in locked memory, and must execute _very_ quickly! It is passed  the  event  flags  that
       triggered   the   call,   which   is   a   bitmask   containing   any   of  the  values  MOUSE_FLAG_MOVE,
       MOUSE_FLAG_LEFT_DOWN,       MOUSE_FLAG_LEFT_UP,        MOUSE_FLAG_RIGHT_DOWN,        MOUSE_FLAG_RIGHT_UP,
       MOUSE_FLAG_MIDDLE_DOWN, MOUSE_FLAG_MIDDLE_UP, and MOUSE_FLAG_MOVE_Z. Note that even if the mouse has more
       than three buttons, only the first three can be trapped using a callback.

       mouse_callback - User specified mouse callback. Allegro game programming library.

install_mouse(3alleg4)

Allegro                                           version 4.4.3                          mouse_callback(3alleg4)

#include<allegro.h>externvoid(*mouse_callback)(intflags);