al_set_render_state - Allegro 5 API

       Set one of several render attributes; see ALLEGRO_RENDER_STATE(3alleg5) for details.

       This function does nothing if the target bitmap is a memory bitmap.

       al_set_render_state - Allegro 5 API

al_get_render_state(3alleg5),       ALLEGRO_RENDER_STATE(3alleg5),      ALLEGRO_RENDER_FUNCTION(3alleg5),
       ALLEGRO_WRITE_MASK_FLAGS(3alleg5)

Allegro reference manual                                                            al_set_render_state(3alleg5)

       5.1.2

              #include <allegro5/allegro.h>

              void al_set_render_state(ALLEGRO_RENDER_STATE state, int value)