Hi there, I understand from the documentation that the install() function returns an object of type install_t. However, install_t seems to be defined as void in SWI-Prolog.h. In other words, code like install_t install() { ppl_initialize(); PL_register_extensions(predicates); } would seem to miss a return statement, but adding a return statement would be an error. So, what is the purpose of install_t? And why there is not something similar for uninstall()? Thanks in advance 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