Function rustler_sys::rustler_sys_api::enif_make_atom_len

pub unsafe extern "C" fn enif_make_atom_len(
    env: *mut ErlNifEnv, 
    name: *const c_uchar, 
    len: size_t
) -> ERL_NIF_TERM

See enif_make_atom_len in the Erlang docs.