CSerialPort串口类最新修正版(解决关闭死锁问题)2014-01-11

这是一份优秀的类文件，好多的地方值得我们学习，具体在多线程，事件，自定义消息，类的封装方面等等。
Remon提供的串口类网址为： http://codeguru.earthweb.com/network/serialport.shtml，
由于已经运行十几年了，原文的问答部分列出来这么多年来的问题，经过网友们的总结，补充和修改原来代码后，整理出一份相对比较完美的代码。

此外还附带一份小项目的源代码，它超越了串口助手，给人一种耳目一新的感觉。亮点如下：

1. 它解决了串口关闭时出现死锁不响应问题，可以直接用到开发的项目上。
2. 并且是扩展了的串口助手，具有通信协议编辑和使用功能，
3. 软件升级检测，值得做软件升级例子使用。
4. 最重要的是源代码很不错，很值得大家去研究。

   分享给需要的朋友们，有问题，可以在留言，以便做进一步修正。

VC串口修正类应用的小项目下载地址：http://download.csdn.net/detail/liquanhai/3763088

2014-01-11补充说明：

最新的CSerialPort类的下载地址在：https://github.com/liquanhai/CSerialPort

头文件CSerialPort.h如下：

/*
**  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
**
**
************************************************************************************
**  author: mrlong date:2007-12-25
**
**  改进
**    1) 增加ClosePort
**    2) 增加 writetoProt() 两个方法
**    3) 增加 SendData 与 RecvData 方法
**************************************************************************************
***************************************************************************************
**  author：liquanhai date:2011-11-04
**  改进
**    1）增加 ClosePort中交出控制权，防止死锁问题
**    2) 增加 ReceiveChar中防止线程死锁
 */

#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();

    // port initialisation
    BOOL        InitPort(CWnd* pPortOwner, UINT portnr = 1, UINT baud = 19200,
                char parity = 'N', UINT databits = 8, UINT stopsbits = 1,
                DWORD dwCommEvents = EV_RXCHAR | EV_CTS, UINT nBufferSize = 512,

                DWORD ReadIntervalTimeout = 1000,
                DWORD ReadTotalTimeoutMultiplier = 1000,
                DWORD ReadTotalTimeoutConstant = 1000,
                DWORD WriteTotalTimeoutMultiplier = 1000,
                DWORD WriteTotalTimeoutConstant = 1000);

    // start/stop comm watching
    BOOL        StartMonitoring();
    BOOL        RestartMonitoring();
    BOOL        StopMonitoring();

    DWORD       GetWriteBufferSize();
    DWORD       GetCommEvents();
    DCB         GetDCB();

    void        WriteToPort(char* string);
    void        WriteToPort(char* string,int n); // add by mrlong 2007-12-25
    void        WriteToPort(LPCTSTR string);     // add by mrlong 2007-12-25
    void        WriteToPort(BYTE* Buffer, int n);// add by mrlong
    void        ClosePort();                     // add by mrlong 2007-12-2

    void SendData(LPCTSTR lpszData, const int nLength);   //串口发送函数 by mrlong 2008-2-15
    BOOL RecvData(LPTSTR lpszData, const int nSize);      //串口接收函数 by mrlong 2008-2-15

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;  //stop发生的事件
    HANDLE              m_hComm;           // read
    HANDLE              m_hWriteEvent;     // write

    // 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;

    int                 m_nWriteSize; //add by mrlong 2007-12-25
};

#endif __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
**
**
************************************************************************************
**  author: mrlong date:2007-12-25
**
**  改进
**    1) 增加ClosePort
**    2) 增加 writetoProt() 两个方法
**    3) 增加 SendData 与 RecvData 方法
**************************************************************************************
***************************************************************************************
**  author：liquanhai date:2011-11-04
**  改进
**    1）增加 ClosePort中交出控制权，防止死锁问题
**    2) 增加 ReceiveChar中防止线程死锁
 */

#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();

	// port initialisation											
	BOOL		InitPort(CWnd* pPortOwner, UINT portnr = 1, UINT baud = 19200, 
				char parity = 'N', UINT databits = 8, UINT stopsbits = 1, 
				DWORD dwCommEvents = EV_RXCHAR | EV_CTS, UINT nBufferSize = 512,
			
				DWORD ReadIntervalTimeout = 1000,
				DWORD ReadTotalTimeoutMultiplier = 1000,
				DWORD ReadTotalTimeoutConstant = 1000,
				DWORD WriteTotalTimeoutMultiplier = 1000,
				DWORD WriteTotalTimeoutConstant = 1000);

	// start/stop comm watching
	BOOL		StartMonitoring();
	BOOL		RestartMonitoring();
	BOOL		StopMonitoring();

	DWORD		GetWriteBufferSize();
	DWORD		GetCommEvents();
	DCB			GetDCB();

	void		WriteToPort(char* string);
	void        WriteToPort(char* string,int n); // add by mrlong 2007-12-25
	void		WriteToPort(LPCTSTR string);     // add by mrlong 2007-12-25
	void        WriteToPort(BYTE* Buffer, int n);// add by mrlong
	void        ClosePort();                     // add by mrlong 2007-12-2  

	void SendData(LPCTSTR lpszData, const int nLength);   //串口发送函数 by mrlong 2008-2-15
	BOOL RecvData(LPTSTR lpszData, const int nSize);      //串口接收函数 by mrlong 2008-2-15

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;  //stop发生的事件
	HANDLE				m_hComm;           // read  
	HANDLE				m_hWriteEvent;     // write

	// 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;

	int                 m_nWriteSize; //add by mrlong 2007-12-25
};

#endif __SERIALPORT_H__

源文件cpp文件如下：

/*
**  FILENAME            CSerialPort.cpp
**
**  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
**
**
*/

#include "stdafx.h"
#include "SerialPort.h"

#include <assert.h>

//
// Constructor
//
CSerialPort::CSerialPort()
{
    m_hComm = NULL;

    // initialize overlapped structure members to zero
    m_ov.Offset = 0;
    m_ov.OffsetHigh = 0;

    // create events
    m_ov.hEvent = NULL;
    m_hWriteEvent = NULL;
    m_hShutdownEvent = NULL;

    m_szWriteBuffer = NULL;

    m_bThreadAlive = FALSE;
    m_nWriteSize = 1;
}

//
// Delete dynamic memory
//
CSerialPort::~CSerialPort()
{
    do
    {
        SetEvent(m_hShutdownEvent);
    } while (m_bThreadAlive);

    if (m_hComm != NULL)
    {
        CloseHandle(m_hComm);
        m_hComm = NULL;
    }
    // Close Handles
    if(m_hShutdownEvent!=NULL)
        CloseHandle( m_hShutdownEvent);
    if(m_ov.hEvent!=NULL)
        CloseHandle( m_ov.hEvent );
    if(m_hWriteEvent!=NULL)
        CloseHandle( m_hWriteEvent );

    TRACE("Thread ended
");

    delete [] m_szWriteBuffer;
}

//
// Initialize the port. This can be port 1 to 4.
//
//
//parity:
//  n=none
//  e=even
//  o=odd
//  m=mark
//  s=space
//data:
//  5,6,7,8
//stop:
//  1,1.5,2
//
BOOL CSerialPort::InitPort(CWnd* pPortOwner,    // the owner (CWnd) of the port (receives message)
                           UINT  portnr,        // portnumber (1..4)
                           UINT  baud,          // baudrate
                           char  parity,        // parity
                           UINT  databits,      // databits
                           UINT  stopbits,      // stopbits
                           DWORD dwCommEvents,  // EV_RXCHAR, EV_CTS etc
                           UINT  writebuffersize,// size to the writebuffer

                           DWORD   ReadIntervalTimeout,
                           DWORD   ReadTotalTimeoutMultiplier,
                           DWORD   ReadTotalTimeoutConstant,
                           DWORD   WriteTotalTimeoutMultiplier,
                           DWORD   WriteTotalTimeoutConstant )

{
    assert(portnr > 0 && portnr < 5);
    assert(pPortOwner != NULL);

    // if the thread is alive: Kill
    if (m_bThreadAlive)
    {
        do
        {
            SetEvent(m_hShutdownEvent);
        } while (m_bThreadAlive);
        TRACE("Thread ended
");
    }

    // create events
    if (m_ov.hEvent != NULL)
        ResetEvent(m_ov.hEvent);
    else
        m_ov.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

    if (m_hWriteEvent != NULL)
        ResetEvent(m_hWriteEvent);
    else
        m_hWriteEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

    if (m_hShutdownEvent != NULL)
        ResetEvent(m_hShutdownEvent);
    else
        m_hShutdownEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

    // initialize the event objects
    m_hEventArray[0] = m_hShutdownEvent;    // highest priority
    m_hEventArray[1] = m_ov.hEvent;
    m_hEventArray[2] = m_hWriteEvent;

    // initialize critical section
    InitializeCriticalSection(&m_csCommunicationSync);

    // set buffersize for writing and save the owner
    m_pOwner = pPortOwner;

    if (m_szWriteBuffer != NULL)
        delete [] m_szWriteBuffer;
    m_szWriteBuffer = new char[writebuffersize];

    m_nPortNr = portnr;

    m_nWriteBufferSize = writebuffersize;
    m_dwCommEvents = dwCommEvents;

    BOOL bResult = FALSE;
    char *szPort = new char[50];
    char *szBaud = new char[50];

    // now it critical!
    EnterCriticalSection(&m_csCommunicationSync);

    // if the port is already opened: close it
    if (m_hComm != NULL)
    {
        CloseHandle(m_hComm);
        m_hComm = NULL;
    }

    // prepare port strings
    sprintf(szPort, "COM%d", portnr);
    // stop is index 0 = 1 1=1.5 2=2
    int mystop;
    int myparity;
    switch(stopbits)
    {
        case 0:
            mystop = ONESTOPBIT;
            break;
        case 1:
            mystop = ONE5STOPBITS;
            break;
        case 2:
            mystop = TWOSTOPBITS;
            break;
    }
    myparity = 0;
    switch(parity)
    {
        case 'N':
            myparity = 0;
            break;
        case 'E':
            myparity = 1;
            break;
        case 'O':
            myparity = 2;
            break;
        case 'M':
            myparity = 3;
            break;
        case 'S':
            myparity = 4;
            break;
    }
    sprintf(szBaud, "baud=%d parity=%c data=%d stop=%d", baud, parity, databits, mystop);

    // get a handle to the port
    m_hComm = CreateFile(szPort,                        // communication port string (COMX)
                         GENERIC_READ | GENERIC_WRITE,  // read/write types
                         0,                             // comm devices must be opened with exclusive access
                         NULL,                          // no security attributes
                         OPEN_EXISTING,                 // comm devices must use OPEN_EXISTING
                         FILE_FLAG_OVERLAPPED,          // Async I/O
                         0);                            // template must be 0 for comm devices

    if (m_hComm == INVALID_HANDLE_VALUE)
    {
        // port not found
        delete [] szPort;
        delete [] szBaud;

        return FALSE;
    }

    // set the timeout values
    m_CommTimeouts.ReadIntervalTimeout         = ReadIntervalTimeout * 1000;
    m_CommTimeouts.ReadTotalTimeoutMultiplier  = ReadTotalTimeoutMultiplier * 1000;
    m_CommTimeouts.ReadTotalTimeoutConstant    = ReadTotalTimeoutConstant * 1000;
    m_CommTimeouts.WriteTotalTimeoutMultiplier = WriteTotalTimeoutMultiplier * 1000;
    m_CommTimeouts.WriteTotalTimeoutConstant   = WriteTotalTimeoutConstant * 1000;

    // configure
    if (SetCommTimeouts(m_hComm, &m_CommTimeouts))
    {
        if (SetCommMask(m_hComm, dwCommEvents))
        {
            if (GetCommState(m_hComm, &m_dcb))
            {
                m_dcb.EvtChar = 'q';
                m_dcb.fRtsControl = RTS_CONTROL_ENABLE;     // set RTS bit high!
                m_dcb.BaudRate = baud;  // add by mrlong
                m_dcb.Parity   = myparity;
                m_dcb.ByteSize = databits;
                m_dcb.StopBits = mystop;

                //if (BuildCommDCB(szBaud, &m_dcb))
                //{
                    if (SetCommState(m_hComm, &m_dcb))
                        ; // normal operation... continue
                    else
                        ProcessErrorMessage("SetCommState()");
                //}
                //else
                //  ProcessErrorMessage("BuildCommDCB()");
            }
            else
                ProcessErrorMessage("GetCommState()");
        }
        else
            ProcessErrorMessage("SetCommMask()");
    }
    else
        ProcessErrorMessage("SetCommTimeouts()");

    delete [] szPort;
    delete [] szBaud;

    // flush the port
    PurgeComm(m_hComm, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT);

    // release critical section
    LeaveCriticalSection(&m_csCommunicationSync);

    TRACE("Initialisation for communicationport %d completed.
Use Startmonitor to communicate.
", portnr);

    return TRUE;
}

//
//  The CommThread Function.
//
UINT CSerialPort::CommThread(LPVOID pParam)
{
    // Cast the void pointer passed to the thread back to
    // a pointer of CSerialPort class
    CSerialPort *port = (CSerialPort*)pParam;

    // Set the status variable in the dialog class to
    // TRUE to indicate the thread is running.
    port->m_bThreadAlive = TRUE;

    // Misc. variables
    DWORD BytesTransfered = 0;
    DWORD Event = 0;
    DWORD CommEvent = 0;
    DWORD dwError = 0;
    COMSTAT comstat;
    BOOL  bResult = TRUE;

    // Clear comm buffers at startup
    if (port->m_hComm)       // check if the port is opened
        PurgeComm(port->m_hComm, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT);

    // begin forever loop.  This loop will run as long as the thread is alive.
    for (;;)
    {

        // Make a call to WaitCommEvent().  This call will return immediatly
        // because our port was created as an async port (FILE_FLAG_OVERLAPPED
        // and an m_OverlappedStructerlapped structure specified).  This call will cause the
        // m_OverlappedStructerlapped element m_OverlappedStruct.hEvent, which is part of the m_hEventArray to
        // be placed in a non-signeled state if there are no bytes available to be read,
        // or to a signeled state if there are bytes available.  If this event handle
        // is set to the non-signeled state, it will be set to signeled when a
        // character arrives at the port.

        // we do this for each port!

        bResult = WaitCommEvent(port->m_hComm, &Event, &port->m_ov);

        if (!bResult)
        {
            // If WaitCommEvent() returns FALSE, process the last error to determin
            // the reason..
            switch (dwError = GetLastError())
            {
            case ERROR_IO_PENDING:
                {
                    // This is a normal return value if there are no bytes
                    // to read at the port.
                    // Do nothing and continue
                    break;
                }
            case 87:
                {
                    // Under Windows NT, this value is returned for some reason.
                    // I have not investigated why, but it is also a valid reply
                    // Also do nothing and continue.
                    break;
                }
            default:
                {
                    // All other error codes indicate a serious error has
                    // occured.  Process this error.
                    port->ProcessErrorMessage("WaitCommEvent()");
                    break;
                }
            }
        }
        else
        {
            // If WaitCommEvent() returns TRUE, check to be sure there are
            // actually bytes in the buffer to read.
            //
            // If you are reading more than one byte at a time from the buffer
            // (which this program does not do) you will have the situation occur
            // where the first byte to arrive will cause the WaitForMultipleObjects()
            // function to stop waiting.  The WaitForMultipleObjects() function
            // resets the event handle in m_OverlappedStruct.hEvent to the non-signelead state
            // as it returns.
            //
            // If in the time between the reset of this event and the call to
            // ReadFile() more bytes arrive, the m_OverlappedStruct.hEvent handle will be set again
            // to the signeled state. When the call to ReadFile() occurs, it will
            // read all of the bytes from the buffer, and the program will
            // loop back around to WaitCommEvent().
            //
            // At this point you will be in the situation where m_OverlappedStruct.hEvent is set,
            // but there are no bytes available to read.  If you proceed and call
            // ReadFile(), it will return immediatly due to the async port setup, but
            // GetOverlappedResults() will not return until the next character arrives.
            //
            // It is not desirable for the GetOverlappedResults() function to be in
            // this state.  The thread shutdown event (event 0) and the WriteFile()
            // event (Event2) will not work if the thread is blocked by GetOverlappedResults().
            //
            // The solution to this is to check the buffer with a call to ClearCommError().
            // This call will reset the event handle, and if there are no bytes to read
            // we can loop back through WaitCommEvent() again, then proceed.
            // If there are really bytes to read, do nothing and proceed.

            bResult = ClearCommError(port->m_hComm, &dwError, &comstat);

            if (comstat.cbInQue == 0)
                continue;
        }   // end if bResult

        // Main wait function.  This function will normally block the thread
        // until one of nine events occur that require action.
        Event = WaitForMultipleObjects(3, port->m_hEventArray, FALSE, INFINITE);

        switch (Event)
        {
        case 0:
            {
                // Shutdown event.  This is event zero so it will be
                // the higest priority and be serviced first.

                port->m_bThreadAlive = FALSE;

                // Kill this thread.  break is not needed, but makes me feel better.
                AfxEndThread(100);
                break;
            }
        case 1: // read event
            {
                GetCommMask(port->m_hComm, &CommEvent);
                if (CommEvent & EV_RXCHAR) //接收到字符，并置于输入缓冲区中
                    ReceiveChar(port, comstat);

                if (CommEvent & EV_CTS) //CTS信号状态发生变化
                    ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_CTS_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
                if (CommEvent & EV_RXFLAG) //接收到事件字符，并置于输入缓冲区中
                    ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_RXFLAG_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
                if (CommEvent & EV_BREAK)  //输入中发生中断
                    ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_BREAK_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
                if (CommEvent & EV_ERR) //发生线路状态错误，线路状态错误包括CE_FRAME,CE_OVERRUN和CE_RXPARITY
                    ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_ERR_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
                if (CommEvent & EV_RING) //检测到振铃指示
                    ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_RING_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);

                break;
            }
        case 2: // write event
            {
                // Write character event from port
                WriteChar(port);
                break;
            }

        } // end switch

    } // close forever loop

    return 0;
}

//
// start comm watching
//
BOOL CSerialPort::StartMonitoring()
{
    if (!(m_Thread = AfxBeginThread(CommThread, this)))
        return FALSE;
    TRACE("Thread started
");
    return TRUE;
}

//
// Restart the comm thread
//
BOOL CSerialPort::RestartMonitoring()
{
    TRACE("Thread resumed
");
    m_Thread->ResumeThread();
    return TRUE;
}


//
// Suspend the comm thread
//
BOOL CSerialPort::StopMonitoring()
{
    TRACE("Thread suspended
");
    m_Thread->SuspendThread();
    return TRUE;
}


//
// If there is a error, give the right message
//
void CSerialPort::ProcessErrorMessage(char* ErrorText)
{
    char *Temp = new char[200];

    LPVOID lpMsgBuf;

    FormatMessage(
        FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
        NULL,
        GetLastError(),
        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
        (LPTSTR) &lpMsgBuf,
        0,
        NULL
    );

    sprintf(Temp, "WARNING:  %s Failed with the following error: 
%s
Port: %d
", (char*)ErrorText, lpMsgBuf, m_nPortNr);
    MessageBox(NULL, Temp, "Application Error", MB_ICONSTOP);

    LocalFree(lpMsgBuf);
    delete[] Temp;
}

//
// Write a character.
//
void CSerialPort::WriteChar(CSerialPort* port)
{
    BOOL bWrite = TRUE;
    BOOL bResult = TRUE;

    DWORD BytesSent = 0;
    DWORD SendLen   = port->m_nWriteSize;
    ResetEvent(port->m_hWriteEvent);


    // Gain ownership of the critical section
    EnterCriticalSection(&port->m_csCommunicationSync);

    if (bWrite)
    {
        // Initailize variables
        port->m_ov.Offset = 0;
        port->m_ov.OffsetHigh = 0;

        // Clear buffer
        PurgeComm(port->m_hComm, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT);

        bResult = WriteFile(port->m_hComm,                           // Handle to COMM Port
                            port->m_szWriteBuffer,                   // Pointer to message buffer in calling finction
                            SendLen,    // add by mrlong
                            //strlen((char*)port->m_szWriteBuffer),  // Length of message to send
                            &BytesSent,                             // Where to store the number of bytes sent
                            &port->m_ov);                            // Overlapped structure

        // deal with any error codes
        if (!bResult)
        {
            DWORD dwError = GetLastError();
            switch (dwError)
            {
                case ERROR_IO_PENDING:
                    {
                        // continue to GetOverlappedResults()
                        BytesSent = 0;
                        bWrite = FALSE;
                        break;
                    }
                default:
                    {
                        // all other error codes
                        port->ProcessErrorMessage("WriteFile()");
                    }
            }
        }
        else
        {
            LeaveCriticalSection(&port->m_csCommunicationSync);
        }
    } // end if(bWrite)

    if (!bWrite)
    {
        bWrite = TRUE;

        bResult = GetOverlappedResult(port->m_hComm, // Handle to COMM port
                                      &port->m_ov,       // Overlapped structure
                                      &BytesSent,       // Stores number of bytes sent
                                      TRUE);            // Wait flag

        LeaveCriticalSection(&port->m_csCommunicationSync);

        // deal with the error code
        if (!bResult)
        {
            port->ProcessErrorMessage("GetOverlappedResults() in WriteFile()");
        }
    } // end if (!bWrite)

    // Verify that the data size send equals what we tried to send
    if (BytesSent != SendLen /*strlen((char*)port->m_szWriteBuffer)*/)  // add by
    {
        TRACE("WARNING: WriteFile() error.. Bytes Sent: %d; Message Length: %d
", BytesSent, strlen((char*)port->m_szWriteBuffer));
    }
}

//
// Character received. Inform the owner
//
void CSerialPort::ReceiveChar(CSerialPort* port, COMSTAT comstat)
{
    BOOL  bRead = TRUE;
    BOOL  bResult = TRUE;
    DWORD dwError = 0;
    DWORD BytesRead = 0;
    unsigned char RXBuff;

    for (;;)
    {
             //add by liquanhai 2011-11-06  防止死锁
             if(WaitForSingleObject(port->m_hShutdownEvent,0)==WAIT_OBJECT_0)
                 return;

                // Gain ownership of the comm port critical section.
        // This process guarantees no other part of this program
        // is using the port object.

        EnterCriticalSection(&port->m_csCommunicationSync);

        // ClearCommError() will update the COMSTAT structure and
        // clear any other errors.

        bResult = ClearCommError(port->m_hComm, &dwError, &comstat);

        LeaveCriticalSection(&port->m_csCommunicationSync);

        // 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;
        }

        EnterCriticalSection(&port->m_csCommunicationSync);

        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)

        LeaveCriticalSection(&port->m_csCommunicationSync);

        // 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);

    memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
    strcpy(m_szWriteBuffer, string);
    m_nWriteSize=strlen(string); // add by mrlong
    // set event for write
    SetEvent(m_hWriteEvent);
}

//
// Return the device control block
//
DCB CSerialPort::GetDCB()
{
    return m_dcb;
}

//
// Return the communication event masks
//
DWORD CSerialPort::GetCommEvents()
{
    return m_dwCommEvents;
}

//
// Return the output buffer size
//
DWORD CSerialPort::GetWriteBufferSize()
{
    return m_nWriteBufferSize;
}

void CSerialPort::ClosePort()
{

/*
**	FILENAME			CSerialPort.cpp
**
**	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
**
**
*/

#include "stdafx.h"
#include "SerialPort.h"

#include <assert.h>
 
//
// Constructor
//
CSerialPort::CSerialPort()
{
	m_hComm = NULL;

	// initialize overlapped structure members to zero
	m_ov.Offset = 0;
	m_ov.OffsetHigh = 0;

	// create events
	m_ov.hEvent = NULL;
	m_hWriteEvent = NULL;
	m_hShutdownEvent = NULL;

	m_szWriteBuffer = NULL;

	m_bThreadAlive = FALSE;
	m_nWriteSize = 1;
}

//
// Delete dynamic memory
//
CSerialPort::~CSerialPort()
{
	do
	{
		SetEvent(m_hShutdownEvent);
	} while (m_bThreadAlive);

	if (m_hComm != NULL)
	{
		CloseHandle(m_hComm);
		m_hComm = NULL;
	}
	// Close Handles  
	if(m_hShutdownEvent!=NULL)
		CloseHandle( m_hShutdownEvent); 
	if(m_ov.hEvent!=NULL)
		CloseHandle( m_ov.hEvent ); 
	if(m_hWriteEvent!=NULL)
		CloseHandle( m_hWriteEvent ); 

	TRACE("Thread ended
");

	delete [] m_szWriteBuffer;
}

//
// Initialize the port. This can be port 1 to 4.
//
//
//parity:
//  n=none
//  e=even
//  o=odd
//  m=mark
//  s=space
//data:
//  5,6,7,8
//stop:
//  1,1.5,2 
//
BOOL CSerialPort::InitPort(CWnd* pPortOwner,	// the owner (CWnd) of the port (receives message)
						   UINT  portnr,		// portnumber (1..4)
						   UINT  baud,			// baudrate
						   char  parity,		// parity 
						   UINT  databits,		// databits 
						   UINT  stopbits,		// stopbits 
						   DWORD dwCommEvents,	// EV_RXCHAR, EV_CTS etc
						   UINT  writebuffersize,// size to the writebuffer
						   
						   DWORD   ReadIntervalTimeout,
						   DWORD   ReadTotalTimeoutMultiplier,
						   DWORD   ReadTotalTimeoutConstant,
						   DWORD   WriteTotalTimeoutMultiplier,
						   DWORD   WriteTotalTimeoutConstant )	

{
	assert(portnr > 0 && portnr < 5);
	assert(pPortOwner != NULL);

	// if the thread is alive: Kill
	if (m_bThreadAlive)
	{
		do
		{
			SetEvent(m_hShutdownEvent);
		} while (m_bThreadAlive);
		TRACE("Thread ended
");
	}

	// create events
	if (m_ov.hEvent != NULL)
		ResetEvent(m_ov.hEvent);
	else
		m_ov.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

	if (m_hWriteEvent != NULL)
		ResetEvent(m_hWriteEvent);
	else
		m_hWriteEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
	
	if (m_hShutdownEvent != NULL)
		ResetEvent(m_hShutdownEvent);
	else
		m_hShutdownEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

	// initialize the event objects
	m_hEventArray[0] = m_hShutdownEvent;	// highest priority
	m_hEventArray[1] = m_ov.hEvent;
	m_hEventArray[2] = m_hWriteEvent;

	// initialize critical section
	InitializeCriticalSection(&m_csCommunicationSync);
	
	// set buffersize for writing and save the owner
	m_pOwner = pPortOwner;

	if (m_szWriteBuffer != NULL)
		delete [] m_szWriteBuffer;
	m_szWriteBuffer = new char[writebuffersize];

	m_nPortNr = portnr;

	m_nWriteBufferSize = writebuffersize;
	m_dwCommEvents = dwCommEvents;

	BOOL bResult = FALSE;
	char *szPort = new char[50];
	char *szBaud = new char[50];

	// now it critical!
	EnterCriticalSection(&m_csCommunicationSync);

	// if the port is already opened: close it
	if (m_hComm != NULL)
	{
		CloseHandle(m_hComm);
		m_hComm = NULL;
	}

	// prepare port strings
	sprintf(szPort, "COM%d", portnr);
	// stop is index 0 = 1 1=1.5 2=2
	int mystop;
	int myparity;
	switch(stopbits)
	{
		case 0:
			mystop = ONESTOPBIT;
			break;
		case 1:
			mystop = ONE5STOPBITS;
			break;
		case 2:
			mystop = TWOSTOPBITS;
			break;
	}
	myparity = 0;
	switch(parity)
	{
		case 'N':
			myparity = 0;
			break;
		case 'E':
			myparity = 1;
			break;
		case 'O':
			myparity = 2;
			break;
		case 'M':
			myparity = 3;
			break;
		case 'S':
			myparity = 4;
			break;
	}
	sprintf(szBaud, "baud=%d parity=%c data=%d stop=%d", baud, parity, databits, mystop);

	// get a handle to the port
	m_hComm = CreateFile(szPort,						// communication port string (COMX)
					     GENERIC_READ | GENERIC_WRITE,	// read/write types
					     0,								// comm devices must be opened with exclusive access
					     NULL,							// no security attributes
					     OPEN_EXISTING,					// comm devices must use OPEN_EXISTING
					     FILE_FLAG_OVERLAPPED,			// Async I/O
					     0);							// template must be 0 for comm devices

	if (m_hComm == INVALID_HANDLE_VALUE)
	{
		// port not found
		delete [] szPort;
		delete [] szBaud;

		return FALSE;
	}

	// set the timeout values
	m_CommTimeouts.ReadIntervalTimeout         = ReadIntervalTimeout * 1000;
	m_CommTimeouts.ReadTotalTimeoutMultiplier  = ReadTotalTimeoutMultiplier * 1000;
	m_CommTimeouts.ReadTotalTimeoutConstant    = ReadTotalTimeoutConstant * 1000;
	m_CommTimeouts.WriteTotalTimeoutMultiplier = WriteTotalTimeoutMultiplier * 1000;
	m_CommTimeouts.WriteTotalTimeoutConstant   = WriteTotalTimeoutConstant * 1000;

	// configure
	if (SetCommTimeouts(m_hComm, &m_CommTimeouts))
	{						   
		if (SetCommMask(m_hComm, dwCommEvents))
		{
			if (GetCommState(m_hComm, &m_dcb))
			{
				m_dcb.EvtChar = 'q';
				m_dcb.fRtsControl = RTS_CONTROL_ENABLE;		// set RTS bit high!
				m_dcb.BaudRate = baud;  // add by mrlong
				m_dcb.Parity   = myparity;
				m_dcb.ByteSize = databits;
				m_dcb.StopBits = mystop;
						
				//if (BuildCommDCB(szBaud, &m_dcb))
				//{
					if (SetCommState(m_hComm, &m_dcb))
						; // normal operation... continue
					else
						ProcessErrorMessage("SetCommState()");
				//}
				//else
				//	ProcessErrorMessage("BuildCommDCB()");
			}
			else
				ProcessErrorMessage("GetCommState()");
		}
		else
			ProcessErrorMessage("SetCommMask()");
	}
	else
		ProcessErrorMessage("SetCommTimeouts()");

	delete [] szPort;
	delete [] szBaud;

	// flush the port
	PurgeComm(m_hComm, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT);

	// release critical section
	LeaveCriticalSection(&m_csCommunicationSync);

	TRACE("Initialisation for communicationport %d completed.
Use Startmonitor to communicate.
", portnr);

	return TRUE;
}

//
//  The CommThread Function.
//
UINT CSerialPort::CommThread(LPVOID pParam)
{
	// Cast the void pointer passed to the thread back to
	// a pointer of CSerialPort class
	CSerialPort *port = (CSerialPort*)pParam;
	
	// Set the status variable in the dialog class to
	// TRUE to indicate the thread is running.
	port->m_bThreadAlive = TRUE;	
		
	// Misc. variables
	DWORD BytesTransfered = 0; 
	DWORD Event = 0;
	DWORD CommEvent = 0;
	DWORD dwError = 0;
	COMSTAT comstat;
	BOOL  bResult = TRUE;
		
	// Clear comm buffers at startup
	if (port->m_hComm)		// check if the port is opened
		PurgeComm(port->m_hComm, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT);

	// begin forever loop.  This loop will run as long as the thread is alive.
	for (;;) 
	{ 

		// Make a call to WaitCommEvent().  This call will return immediatly
		// because our port was created as an async port (FILE_FLAG_OVERLAPPED
		// and an m_OverlappedStructerlapped structure specified).  This call will cause the 
		// m_OverlappedStructerlapped element m_OverlappedStruct.hEvent, which is part of the m_hEventArray to 
		// be placed in a non-signeled state if there are no bytes available to be read,
		// or to a signeled state if there are bytes available.  If this event handle 
		// is set to the non-signeled state, it will be set to signeled when a 
		// character arrives at the port.

		// we do this for each port!

		bResult = WaitCommEvent(port->m_hComm, &Event, &port->m_ov);

		if (!bResult)  
		{ 
			// If WaitCommEvent() returns FALSE, process the last error to determin
			// the reason..
			switch (dwError = GetLastError()) 
			{ 
			case ERROR_IO_PENDING: 	
				{ 
					// This is a normal return value if there are no bytes
					// to read at the port.
					// Do nothing and continue
					break;
				}
			case 87:
				{
					// Under Windows NT, this value is returned for some reason.
					// I have not investigated why, but it is also a valid reply
					// Also do nothing and continue.
					break;
				}
			default:
				{
					// All other error codes indicate a serious error has
					// occured.  Process this error.
					port->ProcessErrorMessage("WaitCommEvent()");
					break;
				}
			}
		}
		else
		{
			// If WaitCommEvent() returns TRUE, check to be sure there are
			// actually bytes in the buffer to read.  
			//
			// If you are reading more than one byte at a time from the buffer 
			// (which this program does not do) you will have the situation occur 
			// where the first byte to arrive will cause the WaitForMultipleObjects() 
			// function to stop waiting.  The WaitForMultipleObjects() function 
			// resets the event handle in m_OverlappedStruct.hEvent to the non-signelead state
			// as it returns.  
			//
			// If in the time between the reset of this event and the call to 
			// ReadFile() more bytes arrive, the m_OverlappedStruct.hEvent handle will be set again
			// to the signeled state. When the call to ReadFile() occurs, it will 
			// read all of the bytes from the buffer, and the program will
			// loop back around to WaitCommEvent().
			// 
			// At this point you will be in the situation where m_OverlappedStruct.hEvent is set,
			// but there are no bytes available to read.  If you proceed and call
			// ReadFile(), it will return immediatly due to the async port setup, but
			// GetOverlappedResults() will not return until the next character arrives.
			//
			// It is not desirable for the GetOverlappedResults() function to be in 
			// this state.  The thread shutdown event (event 0) and the WriteFile()
			// event (Event2) will not work if the thread is blocked by GetOverlappedResults().
			//
			// The solution to this is to check the buffer with a call to ClearCommError().
			// This call will reset the event handle, and if there are no bytes to read
			// we can loop back through WaitCommEvent() again, then proceed.
			// If there are really bytes to read, do nothing and proceed.
		
			bResult = ClearCommError(port->m_hComm, &dwError, &comstat);

			if (comstat.cbInQue == 0)
				continue;
		}	// end if bResult

		// Main wait function.  This function will normally block the thread
		// until one of nine events occur that require action.
		Event = WaitForMultipleObjects(3, port->m_hEventArray, FALSE, INFINITE);

		switch (Event)
		{
		case 0:
			{
				// Shutdown event.  This is event zero so it will be
				// the higest priority and be serviced first.

			 	port->m_bThreadAlive = FALSE;
				
				// Kill this thread.  break is not needed, but makes me feel better.
				AfxEndThread(100);
				break;
			}
		case 1:	// read event
			{
				GetCommMask(port->m_hComm, &CommEvent);
				if (CommEvent & EV_RXCHAR) //接收到字符，并置于输入缓冲区中 
					ReceiveChar(port, comstat);
				
				if (CommEvent & EV_CTS) //CTS信号状态发生变化
					::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_CTS_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
				if (CommEvent & EV_RXFLAG) //接收到事件字符，并置于输入缓冲区中 
					::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_RXFLAG_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
				if (CommEvent & EV_BREAK)  //输入中发生中断
					::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_BREAK_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
				if (CommEvent & EV_ERR) //发生线路状态错误，线路状态错误包括CE_FRAME,CE_OVERRUN和CE_RXPARITY 
					::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_ERR_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
				if (CommEvent & EV_RING) //检测到振铃指示
					::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_RING_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
					
				break;
			}  
		case 2: // write event
			{
				// Write character event from port
				WriteChar(port);
				break;
			}

		} // end switch

	} // close forever loop

	return 0;
}

//
// start comm watching
//
BOOL CSerialPort::StartMonitoring()
{
	if (!(m_Thread = AfxBeginThread(CommThread, this)))
		return FALSE;
	TRACE("Thread started
");
	return TRUE;	
}

//
// Restart the comm thread
//
BOOL CSerialPort::RestartMonitoring()
{
	TRACE("Thread resumed
");
	m_Thread->ResumeThread();
	return TRUE;	
}


//
// Suspend the comm thread
//
BOOL CSerialPort::StopMonitoring()
{
	TRACE("Thread suspended
");
	m_Thread->SuspendThread(); 
	return TRUE;	
}


//
// If there is a error, give the right message
//
void CSerialPort::ProcessErrorMessage(char* ErrorText)
{
	char *Temp = new char[200];
	
	LPVOID lpMsgBuf;

	FormatMessage( 
		FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
		NULL,
		GetLastError(),
		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
		(LPTSTR) &lpMsgBuf,
		0,
		NULL 
	);

	sprintf(Temp, "WARNING:  %s Failed with the following error: 
%s
Port: %d
", (char*)ErrorText, lpMsgBuf, m_nPortNr); 
	MessageBox(NULL, Temp, "Application Error", MB_ICONSTOP);

	LocalFree(lpMsgBuf);
	delete[] Temp;
}

//
// Write a character.
//
void CSerialPort::WriteChar(CSerialPort* port)
{
	BOOL bWrite = TRUE;
	BOOL bResult = TRUE;

	DWORD BytesSent = 0;
	DWORD SendLen   = port->m_nWriteSize;
	ResetEvent(port->m_hWriteEvent);


	// Gain ownership of the critical section
	EnterCriticalSection(&port->m_csCommunicationSync);

	if (bWrite)
	{
		// Initailize variables
		port->m_ov.Offset = 0;
		port->m_ov.OffsetHigh = 0;
     
		// Clear buffer
		PurgeComm(port->m_hComm, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT);

		bResult = WriteFile(port->m_hComm,							// Handle to COMM Port
							port->m_szWriteBuffer,					// Pointer to message buffer in calling finction
							SendLen,    // add by mrlong
							//strlen((char*)port->m_szWriteBuffer),	// Length of message to send
							&BytesSent,								// Where to store the number of bytes sent
							&port->m_ov);							// Overlapped structure

		// deal with any error codes
		if (!bResult)  
		{
			DWORD dwError = GetLastError();
			switch (dwError)
			{
				case ERROR_IO_PENDING:
					{
						// continue to GetOverlappedResults()
						BytesSent = 0;
						bWrite = FALSE;
						break;
					}
				default:
					{
						// all other error codes
						port->ProcessErrorMessage("WriteFile()");
					}
			}
		} 
		else
		{
			LeaveCriticalSection(&port->m_csCommunicationSync);
		}
	} // end if(bWrite)

	if (!bWrite)
	{
		bWrite = TRUE;
	
		bResult = GetOverlappedResult(port->m_hComm,	// Handle to COMM port 
									  &port->m_ov,		// Overlapped structure
									  &BytesSent,		// Stores number of bytes sent
									  TRUE); 			// Wait flag

		LeaveCriticalSection(&port->m_csCommunicationSync);

		// deal with the error code 
		if (!bResult)  
		{
			port->ProcessErrorMessage("GetOverlappedResults() in WriteFile()");
		}	
	} // end if (!bWrite)

	// Verify that the data size send equals what we tried to send
	if (BytesSent != SendLen /*strlen((char*)port->m_szWriteBuffer)*/)  // add by 
	{
		TRACE("WARNING: WriteFile() error.. Bytes Sent: %d; Message Length: %d
", BytesSent, strlen((char*)port->m_szWriteBuffer));
	}
}

//
// Character received. Inform the owner
//
void CSerialPort::ReceiveChar(CSerialPort* port, COMSTAT comstat)
{
	BOOL  bRead = TRUE; 
	BOOL  bResult = TRUE;
	DWORD dwError = 0;
	DWORD BytesRead = 0;
	unsigned char RXBuff;

	for (;;) 
	{ 
             //add by liquanhai 2011-11-06  防止死锁
             if(WaitForSingleObject(port->m_hShutdownEvent,0)==WAIT_OBJECT_0)
                 return;

                // Gain ownership of the comm port critical section.
		// This process guarantees no other part of this program 
		// is using the port object. 
		
		EnterCriticalSection(&port->m_csCommunicationSync);

		// ClearCommError() will update the COMSTAT structure and
		// clear any other errors.
		
		bResult = ClearCommError(port->m_hComm, &dwError, &comstat);

		LeaveCriticalSection(&port->m_csCommunicationSync);

		// 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;
		}
						
		EnterCriticalSection(&port->m_csCommunicationSync);

		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)
				
		LeaveCriticalSection(&port->m_csCommunicationSync);

		// 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);

	memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
	strcpy(m_szWriteBuffer, string);
	m_nWriteSize=strlen(string); // add by mrlong
	// set event for write
	SetEvent(m_hWriteEvent);
}

//
// Return the device control block
//
DCB CSerialPort::GetDCB()
{
	return m_dcb;
}

//
// Return the communication event masks
//
DWORD CSerialPort::GetCommEvents()
{
	return m_dwCommEvents;
}

//
// Return the output buffer size
//
DWORD CSerialPort::GetWriteBufferSize()
{
	return m_nWriteBufferSize;
}

void CSerialPort::ClosePort()
{

        MSG message;
    do
    {
          SetEvent(m_hShutdownEvent);
              if(::PeekMessage(&message,m_pOwner->m_hWnd,0,0,PM_REMOVE))
               {
               ::TranslateMessage(&message);
                ::DispatchMessage(&message);
              }

         } while (m_bThreadAlive);

    // if the port is still opened: close it
    if (m_hComm != NULL)
    {
        CloseHandle(m_hComm);
        m_hComm = NULL;
    }

    // Close Handles
    if(m_hShutdownEvent!=NULL)
        ResetEvent(m_hShutdownEvent);
    if(m_ov.hEvent!=NULL)
        ResetEvent(m_ov.hEvent);
    if(m_hWriteEvent!=NULL)
        ResetEvent(m_hWriteEvent);

    //delete [] m_szWriteBuffer;

}

void CSerialPort::WriteToPort(char* string,int n)
{
    assert(m_hComm != 0);
    memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
    memcpy(m_szWriteBuffer, string, n);
    m_nWriteSize = n;

    // set event for write
    SetEvent(m_hWriteEvent);
}

void CSerialPort::WriteToPort(LPCTSTR string)
{
    assert(m_hComm != 0);
    memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
    strcpy(m_szWriteBuffer, string);
    m_nWriteSize=strlen(string);
    // set event for write
    SetEvent(m_hWriteEvent);
}

void CSerialPort::WriteToPort(BYTE* Buffer, int n)
{
    assert(m_hComm != 0);
    memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
    int i;
    for(i=0; i<n; i++)
    {
        m_szWriteBuffer[i] = Buffer[i];
    }
    m_nWriteSize=n;

    // set event for write
    SetEvent(m_hWriteEvent);
}


void CSerialPort::SendData(LPCTSTR lpszData, const int nLength)
{
    assert(m_hComm != 0);
    memset(m_szWriteBuffer, 0, nLength);
    strcpy(m_szWriteBuffer, lpszData);
    m_nWriteSize=nLength;
    // set event for write
    SetEvent(m_hWriteEvent);
}

BOOL CSerialPort::RecvData(LPTSTR lpszData, const int nSize)
{
    //
    //接收数据
    //
    assert(m_hComm!=0);
    memset(lpszData,0,nSize);
    DWORD mylen  = 0;
    DWORD mylen2 = 0;
    while (mylen<nSize) {
        if(!ReadFile(m_hComm,lpszData,nSize,&mylen2,NULL))
            return FALSE;
        mylen += mylen2;


    }

    return TRUE;
}

        MSG message;
	do
	{
	      SetEvent(m_hShutdownEvent);
              if(::PeekMessage(&message,m_pOwner->m_hWnd,0,0,PM_REMOVE))
               {
               ::TranslateMessage(&message);
                ::DispatchMessage(&message);
              }
               
         } while (m_bThreadAlive);

	// if the port is still opened: close it 
	if (m_hComm != NULL)
	{
		CloseHandle(m_hComm);
		m_hComm = NULL;
	}
	
	// Close Handles  
	if(m_hShutdownEvent!=NULL)
		ResetEvent(m_hShutdownEvent);
	if(m_ov.hEvent!=NULL)
		ResetEvent(m_ov.hEvent);
	if(m_hWriteEvent!=NULL)
		ResetEvent(m_hWriteEvent);			
		
	//delete [] m_szWriteBuffer;
	
}

void CSerialPort::WriteToPort(char* string,int n)
{
	assert(m_hComm != 0);
	memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
	memcpy(m_szWriteBuffer, string, n);
	m_nWriteSize = n;

	// set event for write
	SetEvent(m_hWriteEvent);
}

void CSerialPort::WriteToPort(LPCTSTR string)
{
	assert(m_hComm != 0);
	memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
	strcpy(m_szWriteBuffer, string);
	m_nWriteSize=strlen(string);
	// set event for write
	SetEvent(m_hWriteEvent);
}

void CSerialPort::WriteToPort(BYTE* Buffer, int n)
{
	assert(m_hComm != 0);
	memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
	int i;
	for(i=0; i<n; i++)
	{
		m_szWriteBuffer[i] = Buffer[i];
	}
	m_nWriteSize=n;

	// set event for write
	SetEvent(m_hWriteEvent);
}


void CSerialPort::SendData(LPCTSTR lpszData, const int nLength)
{
	assert(m_hComm != 0);
	memset(m_szWriteBuffer, 0, nLength);
	strcpy(m_szWriteBuffer, lpszData);
	m_nWriteSize=nLength;
	// set event for write
	SetEvent(m_hWriteEvent);
}

BOOL CSerialPort::RecvData(LPTSTR lpszData, const int nSize)
{
	//
	//接收数据
	//
	assert(m_hComm!=0);
	memset(lpszData,0,nSize);
	DWORD mylen  = 0;
	DWORD mylen2 = 0;
	while (mylen<nSize) {
		if(!ReadFile(m_hComm,lpszData,nSize,&mylen2,NULL)) 
			return FALSE;
		mylen += mylen2;

		
	}
	
	return TRUE;
}

VC串口修正类应用的小项目下载地址：http://download.csdn.net/detail/liquanhai/3763088