Query the status of network adapter

Return Value:

• 0: Connected
• 1: Disconnected
• -1: Not available

 

Source Code:

int QueryNetworkAdapterStatus(string guidName)
{
    string str = "\\\\.\\";
    str += guidName;

    HANDLE m_hNetworkCardHandle = ::CreateFileA(
        str.c_str(),
        0,
        FILE_SHARE_READ,
        NULL,
        OPEN_EXISTING,
        0,
        INVALID_HANDLE_VALUE
    );

    if (m_hNetworkCardHandle == INVALID_HANDLE_VALUE)
        return -1;

    ULONG ConnectedState = 0;
    ULONG BytesWritten = 0;
    ULONG OidCode = OID_GEN_MEDIA_CONNECT_STATUS;

    if (0 != ::DeviceIoControl(m_hNetworkCardHandle,
        IOCTL_NDIS_QUERY_GLOBAL_STATS,
        &OidCode,
        sizeof(OidCode),
        &ConnectedState,
        sizeof(ConnectedState),
        &BytesWritten,
        NULL))
    {
        ::CloseHandle(m_hNetworkCardHandle);
        return ConnectedState;
    }
    else {
        ::CloseHandle(m_hNetworkCardHandle);
        return -1;
    }
}