module Blit:sig..end
type('a, 'b)t =src:'a -> src_pos:int -> dst:'b -> dst_pos:int -> len:int -> unit
val string_string : (String.t, String.t) tval string_bigstring : (string, Make_substring.bigstring) tval bigstring_bigstring : (Make_substring.bigstring, Make_substring.bigstring) tval bigstring_string : (Make_substring.bigstring, string) t