老外写的很经典的 serialport.h

 /*
** FILENAME CSerialPort.h
**
** PURPOSE This class can read, write and watch one serial port.
** It sends messages to its owner when something happends on the port
** The class creates a thread for reading and writing so the main
** program is not blocked.
**
** CREATION DATE 15-09-1997
** LAST MODIFICATION 12-11-1997
**
** AUTHOR Remon Spekreijse
**
**
*/
#ifndef __SERIALPORT_H__
#define __SERIALPORT_H__
#define WM_COMM_BREAK_DETECTED WM_USER+1 // A break was detected on input.
#define WM_COMM_CTS_DETECTED WM_USER+2 // The CTS (clear-to-send) signal changed state.
#define WM_COMM_DSR_DETECTED WM_USER+3 // The DSR (data-set-ready) signal changed state.
#define WM_COMM_ERR_DETECTED WM_USER+4 // A line-status error occurred. Line-status errors are CE_FRAME, CE_OVERRUN, and CE_RXPARITY.
#define WM_COMM_RING_DETECTED WM_USER+5 // A ring indicator was detected.
#define WM_COMM_RLSD_DETECTED WM_USER+6 // The RLSD (receive-line-signal-detect) signal changed state.
#define WM_COMM_RXCHAR WM_USER+7 // A character was received and placed in the input buffer.
#define WM_COMM_RXFLAG_DETECTED WM_USER+8 // The event character was received and placed in the input buffer.
#define WM_COMM_TXEMPTY_DETECTED WM_USER+9 // The last character in the output buffer was sent.
class CSerialPort
{
public:
 // contruction and destruction
 CSerialPort();
 virtual ~CSerialPort();
 int m_mode;
 int m_sendlen;
 // port initialisation
 BOOL InitPort(CWnd* pPortOwner, UINT portnr = 1, UINT baud = 9600, char parity = 'N', UINT databits = 8, UINT stopsbits = 1, DWORD dwCommEvents = EV_RXCHAR | EV_CTS, UINT nBufferSize = 512);
 // start/stop comm watching
 BOOL StartMonitoring();
 BOOL RestartMonitoring();
 BOOL StopMonitoring();
 DWORD GetWriteBufferSize();
 DWORD GetCommEvents();
 DCB GetDCB();
 void WriteToPort(char* string);
protected:
 // protected memberfunctions
 void ProcessErrorMessage(char* ErrorText);
 static UINT CommThread(LPVOID pParam);
 static void ReceiveChar(CSerialPort* port, COMSTAT comstat);
 static void WriteChar(CSerialPort* port);
 // thread
 CWinThread* m_Thread;
 // synchronisation objects
 CRITICAL_SECTION m_csCommunicationSync;
 BOOL m_bThreadAlive;
 // handles
 HANDLE m_hShutdownEvent;
public:
 HANDLE m_hComm;
protected:
 HANDLE m_hWriteEvent;
 // Event array.
 // One element is used for each event. There are two event handles for each port.
 // A Write event and a receive character event which is located in the overlapped structure (m_ov.hEvent).
 // There is a general shutdown when the port is closed.
 HANDLE m_hEventArray[3];
 // structures
 OVERLAPPED m_ov;
 COMMTIMEOUTS m_CommTimeouts;
 DCB m_dcb;
 // owner window
 CWnd* m_pOwner;
 // misc
 UINT m_nPortNr;
 char* m_szWriteBuffer;
 DWORD m_dwCommEvents;
 DWORD m_nWriteBufferSize;
};
#endif __SERIALPORT_H__