Returning lists

Hello,
how do i return list from external C++-Functions, especially empty lists?

I tried to follow the examples in the embedding and interfacing manual, 
but it didn't work
(unify did not return EC_succeed).

For example I tried:

// return the empty list:
return unify(EC_word(EC_arg(1), nil()));

or:

return unify(EC_arg(1), nil());

or:

return unify(EC_arg(1), EC_word(nil()));

they all didn't work.
I would be glad if someone could help me out.


   Andreas Strack