In article <1991Apr5.161945.889 at vixvax.mgi.com> cepek at vixvax.mgi.com writes: >Does ANSI really state that > #if ABC == DEF >evaluates to FALSE if symbol DEF is not defined!? No -- undefined identifiers are replaced by 0 in #if expressions. That was existing behavior in e.g. the Reiser CPP.