al_set_window_constraints - Allegro 5 API

       Constrains  a non-fullscreen resizable display.  The constraints are a hint only, and are not necessarily
       respected by the window environment.  A value of 0 for any of the parameters indicates no constraint  for
       that parameter.

       The constraints will be applied to a display only after the al_apply_window_constraints(3alleg5) function
       call.

       al_set_window_constraints - Allegro 5 API

al_apply_window_constraints(3alleg5), al_get_window_constraints(3alleg5)

Allegro reference manual                                                      al_set_window_constraints(3alleg5)

       5.1.0

              #include <allegro5/allegro.h>

              bool al_set_window_constraints(ALLEGRO_DISPLAY *display,
                 int min_w, int min_h, int max_w, int max_h)