Thanks! This is an example (from IBM) I cut-and-paste into Emacs to better understand pthread_once(...). Didn't notice the two "%.8x" in printf(). Thanks again, Jan -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple