I see that one of the definitions each of Perl_isfinite(), Perl_isinf(), and Perl_isfinitel() in perl.h, and the definition of SvPADMY() in sv.h, have a potential precedence problem. Their expansions take the form "!(...)", and so are vulnerable to being broken up by postfix operators. Each of these expansions should have a pair of enclosing parens added. -zeframThread Next