How to discovery connected BLE device on MacOS

MrGuo

Hi,
qt 5.10.1, the program can not discovery BLE device which is already connected to macos, but can find the device when it's disconnected,
Don't know why, and code is very much like the lowenergyscanner example:

  QBluetoothDeviceDiscoveryAgent *m_deviceDiscoveryAgent;
  m_deviceDiscoveryAgent = new QBluetoothDeviceDiscoveryAgent(this);
  m_deviceDiscoveryAgent->setLowEnergyDiscoveryTimeout(5000);

....

  m_deviceDiscoveryAgent->start(QBluetoothDeviceDiscoveryAgent::LowEnergyMethod);

Any ideas on how to discovery the connected devices?