Dear Vitor, we now need to communicate bignums to and from the C interface. I didn't find provision for this in the current interface. What is needed is 1) a predicate to test whether a YAP integer would fit into a long int so that IntOfTerm() can be used; 2) a sort of NumberCharsOfTerm() to get a char* containing the number chars corresponding to a (possibly big) YAP integer; 3) a sort of MkIntFromNumberChars to create a YAP integer out of a char* containing number chars. It would be nice to have these or other equivalent facilities in YAP. What do you think? All the best, Roberto -- Prof. Roberto Bagnara Computer Science Group Department of Mathematics, University of Parma, Italy http://www.cs.unipr.it/~bagnara/ mailto:bagnara@cs.unipr.it