Daniel You keep asking what I find "ugly"... I noticed in xrdfs we have the following pattern: namespace fs { class FileValidator { virtual void whatever() = 0; }; } // end of namespace class FileValidator : public fs::FileValidator { virtual void whatever() {} }; Why not simply: class FileValidatorBase { virtual void whatever() = 0; }; class FileValidator : public FileValidatorBase { virtual void whatever() {} }; Jacek ######################################################################## Use REPLY-ALL to reply to list To unsubscribe from the QSERV-L list, click the following link: https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=QSERV-L&A=1