// start forever loop. I use this type of loop because I // do not know at runtime how many loops this will have to // run. My solution is to start a forever loop and to // break out of it when I have processed all of the // data available. Be careful with this approach and // be sure your loop will exit. // My reasons for this are not as clear in this sample // as it is in my production code, but I have found this // solutiion to be the most efficient way to do this.
if (comstat.cbInQue == 0) { // break out when all bytes have been read break; }
if (bRead) { bResult = ReadFile(port->m_hComm, // Handle to COMM port &RXBuff, // RX Buffer Pointer 1, // Read one byte &BytesRead, // Stores number of bytes read &port->m_ov); // pointer to the m_ov structure // deal with the error code if (!bResult) { switch (dwError = GetLastError()) { case ERROR_IO_PENDING: { // asynchronous i/o is still in progress // Proceed on to GetOverlappedResults(); bRead = FALSE; break; } default: { // Another error has occured. Process this error. port->ProcessErrorMessage("ReadFile()"); break; } } } else { // ReadFile() returned complete. It is not necessary to call GetOverlappedResults() bRead = TRUE; } } // close if (bRead)
if (!bRead) { bRead = TRUE; bResult = GetOverlappedResult(port->m_hComm, // Handle to COMM port &port->m_ov, // Overlapped structure &BytesRead, // Stores number of bytes read TRUE); // Wait flag
// deal with the error code if (!bResult) { port->ProcessErrorMessage("GetOverlappedResults() in ReadFile()"); } } // close if (!bRead)
// notify parent that a byte was received ::SendMessage((port->m_pOwner)->m_hWnd, WM_COMM_RXCHAR, (WPARAM)RXBuff,(LPARAM)port->m_nPortNr); } // end forever loop
}
// // Write a string to the port // void CSerialPort::WriteToPort(char *string) { assert(m_hComm != 0);
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