If a D11 program terminates, its associated APP is terminated cleanly. If the APP is currently executing when its associated D11 program terminates, the protected procedure call executes to completion before the APP terminates. If the APP terminates unexpectedly (because of a memory fault or termination by a signal), the acppcall returns with an error indicating the active context has become unattached (the window system has crashed). When the APP terminates (because of D11 program death or a software fault), the active context creator is notified it should reap the APP. If the APP died cleanly (because its associated process terminated), the housekeeping thread will clean up the data structures associated with the APP's D11 connection. If the APP died of a software fault, the reaper will generate a fatal window system error.