Hi Dan, > Maybe I'm missing something, but the locking mechanism already exists: at some point, your server program has to bind to an IP port to listen for incoming request, and any respectable OS won't let two programs bind to the same port at the same time. So if binding to the input port works, then there *can't* be another instance of the program running (multiple configuration files notwithstanding, but then you'd need a second process anyway).
We actually have a suite of server products which use ports in a flexible way so your idea - although accurate - won't work in our specific case. MRAB and Diez posted some excellent, cross platform approaches to locking a resource. Thanks for your feedback. Regards, Malcolm -- http://mail.python.org/mailman/listinfo/python-list