Function harfbuzz_ft_sys::hb_ft_face_create

pub unsafe extern "C" fn hb_ft_face_create(
    ft_face: FT_Face, 
    destroy: hb_destroy_func_t
) -> *mut hb_face_t

Official harfbuzz documentation:

This one creates a new hb-face for given ft-face. When the returned hb-face is destroyed, the destroy callback is called (if not NULL), with the ft-face passed to it.

The client is responsible to make sure that ft-face is destroyed after hb-face is destroyed.

Most often you don't want this function. You should use either hb_ft_face_create_cached(), or hb_ft_face_create_referenced(). In particular, if you are going to pass NULL as destroy, you probably should use (the more recent) hb_ft_face_create_referenced() instead.