MetaTrader’s built-in alert mechanisms. In MQL4/5, calling
Alert() pops up a message window on the desktop terminal. Calling
Print() writes to the Journal/Experts log. For external alerts,
SendMail() queues an email to the configured address and
SendNotification() pushes a text alert to the MetaTrader mobile app. Thus an EA can notify the trader via on-screen dialogs, emails, or smartphone notifications. For example, an EA might
Alert("Order executed") for beginners, or use
SendNotification("Buy EURUSD now") to send a mobile push to an advanced user.
