无法使用SerialCommHelper在C ++中打开/初始化串行端口

Question

We are using a usb-serial port converter to establish a serial port connection. We've tested it on a computer with no serial port and were able to initialize and send command through the converter to the device successfully. Once we release the .exe file to another PC with the same usb-serial converter, it fails to open com port.

The only thing we thought we need to change in the code is the port number, which we made sure were correct from device manager. COM6 on the working computer, and COM11 on the non-working one. We also tried to change COM11 to COM2 (an unused port number). The PC we try to make it work on does already have 3 real serial port (COM1, 3 and 4), but would they somehow be interfering this port?

We are using SerialCommHelper.cpp code to initialize the port.

HRESULT CSerialCommHelper:: Init(std::string szPortName, DWORD dwBaudRate,BYTE byParity,BYTE byStopBits,BYTE byByteSize) 
{
HRESULT hr = S_OK;
try
{


    m_hDataRx  = CreateEvent(0,0,0,0);

    //open the COM Port
    //LPCWSTR _portName =LPCWSTR( szPortName.c_str());

    wchar_t* wString=new wchar_t[4096];
   MultiByteToWideChar(CP_ACP, 0, szPortName.c_str(), -1, wString, 4096);

    m_hCommPort = ::CreateFile(wString,
                                GENERIC_READ|GENERIC_WRITE,//access ( read and write)
                                0,  //(share) 0:cannot share the COM port                       
                                0,  //security  (None)              
                                OPEN_EXISTING,// creation : open_existing
                                FILE_FLAG_OVERLAPPED,// we want overlapped operation
                                0// no templates file for COM port...
                                );
    if ( m_hCommPort == INVALID_HANDLE_VALUE )
    {
        TRACE ( "CSerialCommHelper : Failed to open COM Port Reason: %d",GetLastError());
        ASSERT ( 0 );
        std::cout << "This is where the error happens" << std::endl;
        return E_FAIL;
    }

And we call this using

if( m_serial.Init(comPort, 38400, 0, 1, 8) != S_OK )

which comPort is set correctly, but Init never returns S_OK.

Any help is appreciated! Thank you!

Answer 1

The COM port name syntax changes for COM10 and higher. You need: "\\\\.\\COM10"

as documented here... http://support.microsoft.com/kb/115831/en-us