PRBool okay = gExitRoutines.RemoveElement((void*)exitRoutine);
if (!gExitRoutines) return NS_ERROR_FAILURE;  PRBool okay = gExitRoutines->RemoveElement((void*)exitRoutine);
NS_UnregisterXPCOMExitRoutine(XPCOMExitRoutine exitRoutine){    PRBool okay = gExitRoutines.RemoveElement((void*)exitRoutine);    return okay ? NS_OK : NS_ERROR_FAILURE;}