基本訊號

訊號僅適用於 GObject 類。它們只能是公共的，這意味著程式碼的任何部分都可以連線處理程式並觸發它們。

public class Emitter : Object {
    // A signal is declared like a method,
    // but with the signal keyword.
    public signal void my_signal ();

    public void send_signal () {
        this.my_signal (); // Send a signal by calling it like a method.
    }
}

void main () {
    var emitter = new Emitter ();
    // Use the connect method of the signal to add an handler.
    emitter.my_signal.connect (() => {
        print ("Received the signal.\n");
    });
    emitter.send_signal ();
    emitter.my_signal (); // You can send a signal from anywhere.
}

如果它們與訊號具有相同的簽名，你還可以使用普通函式作為處理程式。

void main () {
    var emitter = new Emitter ();
    emitter.connect (my_handler);
    emitter.my_signal ();
}

void my_handler () {
    print ("Received the signal.\n");
}