Added a method to DatagramSocket to set whether multicast loopback should be enabled

modules/juce_core/network/juce_Socket.cpp

@@ -741,6 +741,14 @@ bool DatagramSocket::leaveMulticast (const String& multicastIPAddress)
     return SocketHelpers::multicast (handle, multicastIPAddress, lastBindAddress, false);
 }
 
+bool DatagramSocket::setMulticastLoopbackEnabled (bool enable)
+{
+    if (! isBound || handle < 0)
+        return false;
+
+    return SocketHelpers::setOption<bool> (handle, IPPROTO_IP, IP_MULTICAST_LOOP, enable);
+}
+
 bool DatagramSocket::setEnablePortReuse (bool enabled)
 {
    #if JUCE_ANDROID

modules/juce_core/network/juce_Socket.h

@@ -315,18 +315,24 @@ public:
     void shutdown();
 
     //==============================================================================
-    /** Join a multicast group
+    /** Join a multicast group.
 
         @returns true if it succeeds.
     */
     bool joinMulticast (const String& multicastIPAddress);
 
-    /** Leave a multicast group
+    /** Leave a multicast group.
 
         @returns true if it succeeds.
     */
     bool leaveMulticast (const String& multicastIPAddress);
 
+    /** Enables or disables multicast loopback.
+
+        @returns true if it succeeds.
+    */
+    bool setMulticastLoopbackEnabled (bool enableLoopback);
+
     //==============================================================================
     /** Allow other applications to re-use the port.