set_mouse_range - Man Page

#include <allegro.h>

void set_mouse_range(int x1, int y1, int x2, int y2);

Sets the area of the screen within which the mouse can move. Pass the top  left corner and the bottom right corner (inclusive). If you don't call  this function the range defaults to (0, 0, SCREEN_W-1, SCREEN_H-1).

install_mouse(3), set_mouse_speed(3), position_mouse(3)

install_mouse(3), position_mouse(3), set_mouse_speed(3).