hCom = INVALID HANDLE VALUE;

-------------------------------------------------------int fastcall TComPort::Open(int n)

bool ierr;

AnsiString ComName;

ComName = \\\\.\\COM +IntToStr(n);

if(hCom != INVALID HANDLE VALUE) Close();

hCom = CreateFile(ComName.c str(), GENERIC READGENERIC WRITE, 0, 0,

OPEN EXISTING, FILE ATTRIBUTE NORMALFILE FLAG OVERLAPPED,

if (hCom == INVALID HANDLE VALUE) throw Exception ( Невозможно открыть порт COM +IntToStr(n)); SetupComm(hCom, 2048, 2048);

GetCommTimeouts(hCom, &Timeouts);

Timeouts.ReadIntervalTimeout = MAXDWORD;

Timeouts.ReadTotalTimeoutMultiplier = 0; Timeouts.ReadTotalTimeoutConstant = 0; Timeouts.WriteTotalTimeoutMultiplier = 0; Timeouts.WriteTotalTimeoutConstant = 0; ierr = SetCommTimeouts(hCom, &Timeouts);

if(!ierr) throw Exception ( Ошибка инициализации порта COM +IntToStr(n));

GetCommState(hCom, &dcbBuf); dcbBuf.BaudRate = iBaudRate; dcbBuf.fBinary = true; dcbBuf.fParity = false;

dcbBuf.ByteSize = 8; dcbBuf.Parity = 0; dcbBuf.StopBits = 0; ierr = SetCommState(hCom, &dcbBuf);

if(!ierr) throw Exception ( Ошибка инициализации порта COM +IntToStr(n));

ierr = SetCommMask(hCom, EV RXCHAR);

if(!ierr) throw Exception ( Ошибка инициализации порта COM +IntToStr(n));

return iComNumber = n;

--------------------------------------------------int fastcall TComPort::Open(void)

return Open(iComNumber);

-------------------------------------------------void fastcall TComPort::Close(void)

CloseHandle(hCom);

hCom = INVALID HANDLE VALUE;

-------------------------------------------------void fastcall TComPort::FlushBuffers(void)

PurgeComm(hCom, PURGE TXABORTPURGE TXCLEARPURGE RXABORTPURGE RXCLEAR);

--------------------------------------------------DWORD fastcall TComPort::WriteBlock(void *buf, int count)

DWORD realCount;

WriteFile(hCom, buf, count, &realCount, &OverlappedStructure); return realCount;

---------------------------------------------------DWORD fastcall TComPort::ReadBlock(void *buf, int count)

DWORD realCount;

bool bResult = ReadFile(hCom, buf, count, &realCount, &OverlappedStructure);

if there was a problem, or the async. operations still pending ... if(!bResult) {

deal with the error code switch(GetLastError())

case ERROR HANDLE EOF:

were reached the end of the file during the call to ReadFile code to handle that throw Exception( 1 );

case ERROR IO PENDING:

asynchronous i/o is still in progress do something else for a while

Sleep(100);

check on the results of the asynchronous read bResult = GetOverlappedResult(hCom, &OverlappedStructure, &realCount, false);

if there was a problem ...

if(!bResult) {

deal with the error code switch(GetLastError())

case ERROR HANDLE EOF:

were reached the end of the file during asynchronous operation throw Exception( 2 );

deal with other error cases default:

throw Exception( 3 );