🚀 go-pugleaf

I have absolutely no clue why I can't get this simple test to
work. All it does is open a port, and write to it and read from
it.

The write seems to work because no errors are reported and the
number of bytes written are correct. The read, OTOH reports
nada - no errors and no data.

//--------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner) : TForm(Owner)
{
    hCom = ::CreateFile( TEXT("COM1"), GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL );
    if( hCom == INVALID_HANDLE_VALUE ) throw ComException( "Open Failed", ::GetLastError() );

    FDCB.DCBlength = sizeof( DCB );
    if( ! ::GetCommState(hCom, &FDCB) )
      {
          ::CloseHandle( hCom );
          hCom = INVALID_HANDLE_VALUE;
          throw ComException( "Get State Failed", ::GetLastError() );
      }

    FDCB.BaudRate  =        9600;
    FDCB.ByteSize  =           8;
    FDCB.Parity    =    NOPARITY;
    FDCB.StopBits  =  ONESTOPBIT;
    if( ! ::SetCommState(hCom, &FDCB) )
      {
          ::CloseHandle( hCom );
          hCom = INVALID_HANDLE_VALUE;
          throw ComException( "Set State Failed", ::GetLastError() );
      }

    if( ! ::SetupComm(hCom, 1024*32, 1024*9) )
      {
          ::CloseHandle( hCom );
          hCom = INVALID_HANDLE_VALUE;
          throw ComException( "Setup Failed", ::GetLastError() );
      }

    FTimeOuts.ReadIntervalTimeout         =  15;
    FTimeOuts.ReadTotalTimeoutMultiplier  =   1;
    FTimeOuts.ReadTotalTimeoutConstant    = 250;
    FTimeOuts.WriteTotalTimeoutMultiplier =   1;
    FTimeOuts.WriteTotalTimeoutConstant   = 250;
    if( ! ::SetCommTimeouts(hCom, &FTimeOuts) )
      {
          ::CloseHandle( hCom );
          hCom = INVALID_HANDLE_VALUE;
          throw ComException( "Set Timeouts Failed", ::GetLastError() );
      }
}
//--------------------------------------------------------------
__fastcall TForm1::~TForm1()
{
    if( hCom != INVALID_HANDLE_VALUE ) ::CloseHandle( hCom );
}
//--------------------------------------------------------------
void __fastcall TForm1::Button1Click(TObject *Sender)
{
    if( hCom != INVALID_HANDLE_VALUE )
      {
          DWORD nBytes;
          AnsiString c = "Test String";
          if( ! ::WriteFile( hCom, c.c_str(), c.Length(), &nBytes, NULL) )
	    {
                 throw ComException( "Write Failed " + SysErrorMessage(::GetLastError()), ::GetLastError() );
            }
          ShowMessage("Write " + IntToStr(nBytes) );
      }
}
//--------------------------------------------------------------
void __fastcall TForm1::Button2Click(TObject *Sender)
{
    if( hCom != INVALID_HANDLE_VALUE )
      {
          DWORD nBytes = 0;
          char Buffer[ 101 ] = { 0 };
          if( ! ::ReadFile(hCom, &Buffer, 100, &nBytes, NULL) )
            {
                throw ComException( "Read Failed " + SysErrorMessage(::GetLastError()), ::GetLastError() );
            }
          else ShowMessage( IntToStr(nBytes) + " " + Buffer );
      }
}
//--------------------------------------------------------------

~ JD