Allegro 5 api
#include <allegro5/allegro.h> void al_set_new_display_refresh_rate(int refresh_rate)
Sets the refresh rate to use when creating new displays on the calling thread. If the refresh rate is not available, al_create_display(3alleg5) will fail. A list of modes with refresh rates can be found with al_get_num_display_modes(3alleg5) and al_get_display_mode(3alleg5).
The default setting is zero (don\[aq]t care).
al_get_new_display_refresh_rate(3alleg5)