mac screensaver start event

Question

Is there an event fired when screensaver starts? Like for keychain locking:

OSStatus keychain_locked(SecKeychainEvent keychainEvent, SecKeychainCallbackInfo          


        

Answer 1

This isn't exactly an answer to the question, but I spent a lot of time looking in vain for a list of the notifications posted by macOS, so I wanted to post some code I wrote for notification discovery.

The code simply signs up to listen to all notifications, and prints some info for each as it comes in.

import Foundation

let distCenter = CFNotificationCenterGetDistributedCenter()
if distCenter == nil {
    exit(1)
}

CFNotificationCenterAddObserver(distCenter, nil, { (center, observer, name, object, userInfo) -> Void in
        print("Event occurred: \(name)  User info: \(userInfo)")
    }, nil, nil, .DeliverImmediately)

CFRunLoopRun()