Служба DisplayWrangler отправляет уведомления о том, когда дисплей выключится:
// Doesn't include error checking - just a quick example
io_service_t displayWrangler;
IONotificationPortRef notificationPort;
io_object_t notification;
displayWrangler = IOServiceGetMatchingService(kIOMasterPortDefault, IOServiceNameMatching("IODisplayWrangler");
notificationPort = IONotificationPortCreate(kIOMasterPortDefault);
IOServiceAddInterestNotification(notificationPort, displayWrangler, kIOGeneralInterest, displayPowerNotificationsCallback, NULL, ¬ification);
CFRunLoopAddSource (CFRunLoopGetCurrent(), IONotificationPortGetRunLoopSource(notificationPort), kCFRunLoopDefaultMode);
IOObjectRelease (displayWrangler);
Тогда обратный вызов выглядит примерно так:
void displayPowerNotificationsCallback(void *refcon, io_service_t service, natural_t messageType, void *messageArgument)
{
switch (messageType) {
case kIOMessageDeviceWillPowerOff :
// This is called twice - once for display dim event, then once
// for display power off
break;
case kIOMessageDeviceHasPoweredOn :
// Display powering back on
break;
}
}