After IORegisterForSystemPower failing to call IODeregisterForSystemPower - objective-c

Question

I have an application, written in Objective-C for MacOS 10.10+ which registers for sleep/wake notifications (code sample below, but the code isn't the question). What I am wondering is, if I call IORegisterForSystemPower at App initialisation, but during debugging I kill the app before it has a chance to call IODeregisterForSystemPower, what are the implications? Does the app get de-registered automatically when it dies in any case? Is there a system dictionary I need to clear out (a plist somewhere, etc.)? Thanks in advance for any help.
io_object_t root_notifier = MACH_PORT_NULL;
IONotificationPortRef notify = NULL;
DebugLog(#"App: Logging IORegisterForSystemPower sleep/wake notifications %#", [NSDate date]);
/* Log sleep/wake messages */
powerCallbackPort = IORegisterForSystemPower ((__bridge void *)self, &notify, sleepWakeCallback, &root_notifier);
if ( powerCallbackPort == IO_OBJECT_NULL ) {
DebugLog(#"IORegisterForSystemPower failed");
return;
}
self.rootNotifierPtr = &(root_notifier); // MARK: deregister with this pointer
if ( notify && powerCallbackPort )
{
CFRunLoopAddSource(CFRunLoopGetCurrent(),IONotificationPortGetRunLoopSource(notify), kCFRunLoopDefaultMode);
}

Answer 1

To be honest, I don't know the exact answer. But it may help you.
First of, if you call IORegisterForSystemPower, you need to make two calls in this order: - Call IODeregisterForSystemPower with the 'notifier' argument returned here. - Then call IONotificationPortDestroy passing the 'thePortRef' argument returned here (Please visit apple's document for more detail).
In case of port binding, if I use CFSocketSetAddress, before releasing this socket no other can use this port for binding. But in case of app terminate/closed without releasing this socket this port is available. That means after terminated the app system automatically releasing this.
Does the app get de-registered automatically when it dies in any case?
I think it will automatically de-registered by system.
I also used similar code as you in one of my project. But recently replaced with below codes:
[[[NSWorkspace sharedWorkspace] notificationCenter] addObserver: self selector: #selector(receiveWakeNotification:) name: NSWorkspaceDidWakeNotification object: nil];
[[[NSWorkspace sharedWorkspace] notificationCenter] addObserver: self selector: #selector(receiveSleepNotification:) name: NSWorkspaceWillSleepNotification object: nil];