Fixed the accidental removal of UDP listening of startup

src/QGCCore.cc

@@ -171,6 +171,28 @@ QGCCore::QGCCore(int &argc, char* argv[]) : QApplication(argc, argv)
     if (upgraded) mainWindow->showInfoMessage(tr("Default Settings Loaded"),
                                               tr("APM Planner has been upgraded from version %1 to version %2. Some of your user preferences have been reset to defaults for safety reasons. Please adjust them where needed.").arg(lastApplicationVersion).arg(QGC_APPLICATION_VERSION));
 
+    // Check if link could be connected
+    if (!udpLink->connect())
+    {
+        QMessageBox msgBox;
+        msgBox.setIcon(QMessageBox::Critical);
+        msgBox.setText("Could not connect UDP port. Is an instance of " + qAppName() + "already running?");
+        msgBox.setInformativeText("You will not be able to receive data via UDP. Please check that you're running the right executable and then re-start " + qAppName() + ". Do you want to close the application?");
+        msgBox.setStandardButtons(QMessageBox::Yes | QMessageBox::No);
+        msgBox.setDefaultButton(QMessageBox::No);
+        int ret = msgBox.exec();
+
+        // Close the message box shortly after the click to prevent accidental clicks
+        QTimer::singleShot(15000, &msgBox, SLOT(reject()));
+
+        // Exit application
+        if (ret == QMessageBox::Yes)
+        {
+            //mainWindow->close();
+            QTimer::singleShot(200, mainWindow, SLOT(close()));
+        }
+    }
+
 }
 
 /**

src/comm/UDPLink.cc

@@ -50,6 +50,7 @@ UDPLink::UDPLink(QHostAddress host, quint16 port)
 	this->name = tr("UDP Link (port:%1)").arg(this->port);
 	emit nameChanged(this->name);
     // LinkManager::instance()->add(this);
+    qDebug() << "UDP Created " << name;
 }
 
 UDPLink::~UDPLink()
@@ -104,7 +105,7 @@ void UDPLink::setPort(int port)
  */
 void UDPLink::addHost(const QString& host)
 {
-    //qDebug() << "UDP:" << "ADDING HOST:" << host;
+    qDebug() << "UDP:" << "ADDING HOST:" << host;
     if (host.contains(":"))
     {
         //qDebug() << "HOST: " << host.split(":").first();