Hi Andreas I had a brief look at getting cufflinks to work with the new liblemon but did not make any progress.
For now, I suggest making the following change (similar to Gianfranco's above). @@ -67,9 +67,9 @@ namespace lemon { } ExceptionMember& operator=(const ExceptionMember& copy) { - if (ptr.get() == 0) return; + if (ptr.get() == 0) return NULL; try { - if (!copy.valid()) return; + if (!copy.valid()) return NULL; *ptr = copy.get(); } catch (...) {} } With this in place, cufflinks builds with GCC 6, and I don't believe it makes the situation any worse than it was with GCC 5; if those code paths were followed, the return values would have been undefined anyway. Regards Graham