QNEXTE calls the SNOMAN routine QNEXT which implements the main event loop. It starts by calling MZWIPE to clear memory, thus ensuring that, if a store full occurs, it will recover properly, because these errors always force QNEXT to be called again. Next it calls EVMAIN which is the control routine that processes a single event. It then loops back to MZWIPE until some termination condition is achieved at which time ZEND is called.