How to tell if NSWorkspaceWillPowerOffNotification is caused by a restart or a shutdown?

Question

I'm developing a Cocoa app and I need to perform different actions before the app get closed. I need to know when the app is closed due to a restart and when due to a shutdown.

Through NSWorkspaceWillPowerOffNotification the app recieves a notification regardless of the fact that it's a restart or a shutdown.

Is there a way to identify the cause of poweroff?

Answer 1

you probably don't need to use NSWorkspaceWillPowerOffNotification and you can just use the applicationShouldTerminate: delegate with the code below. your app is getting terminated anyway if the system is getting restarted/shutdown or the user is logging out.

from Apple Developer Forum : How to determine if an application "quit" is because of a logout or restart/shutdown?

https://developer.apple.com/forums/thread/94126

//#import <Foundation/Foundation.h>
//#import <Carbon/Carbon.h> // for kEventParamReason

- (NSApplicationTerminateReply)applicationShouldTerminate:(NSApplication *)sender
{
    NSAppleEventDescriptor* appleEventDesc = [[NSAppleEventManager sharedAppleEventManager] currentAppleEvent];
    NSAppleEventDescriptor* whyDesc = [appleEventDesc attributeDescriptorForKeyword:kEventParamReason];
    OSType why = [whyDesc typeCodeValue];
    switch (why) {
        case kAEShutDown: {
            NSLog(@"kAEShutDown");
            break;
        }
        case kAERestart: {
            NSLog(@"kAERestart");
            break;
        }
        case kAEReallyLogOut: {
            NSLog(@"kAEReallyLogOut");
            break;
        }
    }
    ...
    return NSTerminateNow;
}