I am trying to connect to the StateChanged D-Bus signal, with the following code :-

const QString s_NMService( "org.freedesktop.NetworkManager" );
const QString s_NMObjectPath( "/org/freedesktop/NetworkManager" );
const QString s_NMInterface( "org.freedesktop.NetworkManager" );

CNetworkManager::CNetworkManager(QObject *parent)
		: QObject(parent),
//QDBusInterface's constructor makes a non-obvious blocking call to introspect the D-Bus service
		m_NM( s_NMService, s_NMObjectPath, s_NMInterface, QDBusConnection::systemBus() )
{
	const QVariant VarState( m_NM.property( "State" )  );
	m_NMState = static_cast<ENMState>( VarState.toUInt() );

	m_bWasConnected = QDBusConnection::systemBus().connect(
						s_NMService, s_NMObjectPath, s_NMInterface,
						"StateChanged", "(u)",
						this, SLOT(SetNMState(uint)) );
	m_Connect = connect( &m_NM, SIGNAL(StateChanged(uint)), this, SLOT(SetNMState(uint)) );

However, my debugger tells me that, although the State is correctly fetched initially, the slot function is not called (it should be called twice, of course, since I tried to connect in 2 different ways).

I have noticed this so in some sense I am in a better situation ;-)

Clearly networkmanager is not the problem :-

~$ nmcli monitor 
NetworkManager is running
enp0s3: deactivating
enp0s3: disconnected
There's no primary connection
Networkmanager is now in the 'connected (local only)' state
Connectivity is now 'limited'
enp0s3: using connection 'netplan-enp0s3'
enp0s3: connecting (prepare)
Networkmanager is now in the 'connecting' state
enp0s3: connecting (configuring)
enp0s3: connecting (getting IP configuration)
'netplan-enp0s3' is now the primary connection
enp0s3: connecting (checking IP connectivity)
enp0s3: connecting (starting secondary connections)
enp0s3: connected
Networkmanager is now in the 'connected (site only)' state
Networkmanager is now in the 'connected' state
Connectivity is now 'full'

I've checked the names and variable types using D-Feet.

I also tried running with sudo privileges.

Now I've run out of ideas.

Qt v6.8.3

If anyone with experience can spot my mistake, it would be appreciated, otherwise I will have to revert to the ugly polling option.

TIA

Tim