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：

1. /*
2. **  FILENAME            CSerialPort.h
3. **
4. **  PURPOSE             This class can read, write and watch one serial port.
5. **                      It sends messages to its owner when something happends on the port
6. **                      The class creates a thread for reading and writing so the main
7. **                      program is not blocked.
8. **
9. **  CREATION DATE       15-09-1997
10. **  LAST MODIFICATION   12-11-1997
11. **
12. **  AUTHOR              Remon Spekreijse
13. **
14. **
15. ************************************************************************************
16. **  author: mrlong date:2007-12-25
17. **
18. **  改进
19. **    1) 增加ClosePort
20. **    2) 增加 writetoProt() 两个方法
21. **    3) 增加 SendData 与 RecvData 方法
22. **************************************************************************************
23. ***************************************************************************************
24. **  author：liquanhai date:2011-11-04
25. **  改进
26. **    1）增加 ClosePort中交出控制权，防止死锁问题
27. **    2) 增加 ReceiveChar中防止线程死锁
28. */
29. #ifndef __SERIALPORT_H__
30. #define __SERIALPORT_H__
31. #define WM_COMM_BREAK_DETECTED      WM_USER+1   // A break was detected on input.
32. #define WM_COMM_CTS_DETECTED        WM_USER+2   // The CTS (clear-to-send) signal changed state.
33. #define WM_COMM_DSR_DETECTED        WM_USER+3   // The DSR (data-set-ready) signal changed state.
34. #define WM_COMM_ERR_DETECTED        WM_USER+4   // A line-status error occurred. Line-status errors are CE_FRAME, CE_OVERRUN, and CE_RXPARITY.
35. #define WM_COMM_RING_DETECTED       WM_USER+5   // A ring indicator was detected.
36. #define WM_COMM_RLSD_DETECTED       WM_USER+6   // The RLSD (receive-line-signal-detect) signal changed state.
37. #define WM_COMM_RXCHAR              WM_USER+7   // A character was received and placed in the input buffer.
38. #define WM_COMM_RXFLAG_DETECTED     WM_USER+8   // The event character was received and placed in the input buffer.
39. #define WM_COMM_TXEMPTY_DETECTED    WM_USER+9   // The last character in the output buffer was sent.
40. class CSerialPort
41. {
42. public:
43. // contruction and destruction
44. CSerialPort();
45. virtual     ~CSerialPort();
46. // port initialisation
47. BOOL        InitPort(CWnd* pPortOwner, UINT portnr = 1, UINT baud = 19200,
48. char parity = 'N', UINT databits = 8, UINT stopsbits = 1,
49. DWORD dwCommEvents = EV_RXCHAR | EV_CTS, UINT nBufferSize = 512,
50. DWORD ReadIntervalTimeout = 1000,
51. DWORD ReadTotalTimeoutMultiplier = 1000,
52. DWORD ReadTotalTimeoutConstant = 1000,
53. DWORD WriteTotalTimeoutMultiplier = 1000,
54. DWORD WriteTotalTimeoutConstant = 1000);
55. // start/stop comm watching
56. BOOL        StartMonitoring();
57. BOOL        RestartMonitoring();
58. BOOL        StopMonitoring();
59. DWORD       GetWriteBufferSize();
60. DWORD       GetCommEvents();
61. DCB         GetDCB();
62. void        WriteToPort(char* string);
63. void        WriteToPort(char* string,int n); // add by mrlong 2007-12-25
64. void        WriteToPort(LPCTSTR string);     // add by mrlong 2007-12-25
65. void        WriteToPort(BYTE* Buffer, int n);// add by mrlong
66. void        ClosePort();                     // add by mrlong 2007-12-2
67. void SendData(LPCTSTR lpszData, const int nLength);   //串口发送函数 by mrlong 2008-2-15
68. BOOL RecvData(LPTSTR lpszData, const int nSize);      //串口接收函数 by mrlong 2008-2-15
69. protected:
70. // protected memberfunctions
71. void        ProcessErrorMessage(char* ErrorText);
72. static UINT CommThread(LPVOID pParam);
73. static void ReceiveChar(CSerialPort* port, COMSTAT comstat);
74. static void WriteChar(CSerialPort* port);
75. // thread
76. CWinThread*         m_Thread;
77. // synchronisation objects
78. CRITICAL_SECTION    m_csCommunicationSync;
79. BOOL                m_bThreadAlive;
80. // handles
81. HANDLE              m_hShutdownEvent;  //stop发生的事件
82. HANDLE              m_hComm;           // read
83. HANDLE              m_hWriteEvent;     // write
84. // Event array.
85. // One element is used for each event. There are two event handles for each port.
86. // A Write event and a receive character event which is located in the overlapped structure (m_ov.hEvent).
87. // There is a general shutdown when the port is closed.
88. HANDLE              m_hEventArray[3];
89. // structures
90. OVERLAPPED          m_ov;
91. COMMTIMEOUTS        m_CommTimeouts;
92. DCB                 m_dcb;
93. // owner window
94. CWnd*               m_pOwner;
95. // misc
96. UINT                m_nPortNr;        //?????
97. char*               m_szWriteBuffer;
98. DWORD               m_dwCommEvents;
99. DWORD               m_nWriteBufferSize;
100. int                 m_nWriteSize; //add by mrlong 2007-12-25
101. };
102. #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：

1. /*
2. **  FILENAME            CSerialPort.cpp
3. **
4. **  PURPOSE             This class can read, write and watch one serial port.
5. **                      It sends messages to its owner when something happends on the port
6. **                      The class creates a thread for reading and writing so the main
7. **                      program is not blocked.
8. **
9. **  CREATION DATE       15-09-1997
10. **  LAST MODIFICATION   12-11-1997
11. **
12. **  AUTHOR              Remon Spekreijse
13. **
14. **
15. */
16. #include "stdafx.h"
17. #include "SerialPort.h"
18. #include <assert.h>
19. //
20. // Constructor
21. //
22. CSerialPort::CSerialPort()
23. {
24. m_hComm = NULL;
25. // initialize overlapped structure members to zero
26. m_ov.Offset = 0;
27. m_ov.OffsetHigh = 0;
28. // create events
29. m_ov.hEvent = NULL;
30. m_hWriteEvent = NULL;
31. m_hShutdownEvent = NULL;
32. m_szWriteBuffer = NULL;
33. m_bThreadAlive = FALSE;
34. m_nWriteSize = 1;
35. }
36. //
37. // Delete dynamic memory
38. //
39. CSerialPort::~CSerialPort()
40. {
41. do
42. {
43. SetEvent(m_hShutdownEvent);
44. } while (m_bThreadAlive);
45. if (m_hComm != NULL)
46. {
47. CloseHandle(m_hComm);
48. m_hComm = NULL;
49. }
50. // Close Handles
51. if(m_hShutdownEvent!=NULL)
52. CloseHandle( m_hShutdownEvent);
53. if(m_ov.hEvent!=NULL)
54. CloseHandle( m_ov.hEvent );
55. if(m_hWriteEvent!=NULL)
56. CloseHandle( m_hWriteEvent );
57. TRACE("Thread ended\n");
58. delete [] m_szWriteBuffer;
59. }
60. //
61. // Initialize the port. This can be port 1 to 4.
62. //
63. //
64. //parity:
65. //  n=none
66. //  e=even
67. //  o=odd
68. //  m=mark
69. //  s=space
70. //data:
71. //  5,6,7,8
72. //stop:
73. //  1,1.5,2
74. //
75. BOOL CSerialPort::InitPort(CWnd* pPortOwner,    // the owner (CWnd) of the port (receives message)
76. UINT  portnr,        // portnumber (1..4)
77. UINT  baud,          // baudrate
78. char  parity,        // parity
79. UINT  databits,      // databits
80. UINT  stopbits,      // stopbits
81. DWORD dwCommEvents,  // EV_RXCHAR, EV_CTS etc
82. UINT  writebuffersize,// size to the writebuffer
83. DWORD   ReadIntervalTimeout,
84. DWORD   ReadTotalTimeoutMultiplier,
85. DWORD   ReadTotalTimeoutConstant,
86. DWORD   WriteTotalTimeoutMultiplier,
87. DWORD   WriteTotalTimeoutConstant )
88. {
89. assert(portnr > 0 && portnr < 5);
90. assert(pPortOwner != NULL);
91. // if the thread is alive: Kill
92. if (m_bThreadAlive)
93. {
94. do
95. {
96. SetEvent(m_hShutdownEvent);
97. } while (m_bThreadAlive);
98. TRACE("Thread ended\n");
99. }
100. // create events
101. if (m_ov.hEvent != NULL)
102. ResetEvent(m_ov.hEvent);
103. else
104. m_ov.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
105. if (m_hWriteEvent != NULL)
106. ResetEvent(m_hWriteEvent);
107. else
108. m_hWriteEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
109. if (m_hShutdownEvent != NULL)
110. ResetEvent(m_hShutdownEvent);
111. else
112. m_hShutdownEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
113. // initialize the event objects
114. m_hEventArray[0] = m_hShutdownEvent;    // highest priority
115. m_hEventArray[1] = m_ov.hEvent;
116. m_hEventArray[2] = m_hWriteEvent;
117. // initialize critical section
118. InitializeCriticalSection(&m_csCommunicationSync);
119. // set buffersize for writing and save the owner
120. m_pOwner = pPortOwner;
121. if (m_szWriteBuffer != NULL)
122. delete [] m_szWriteBuffer;
123. m_szWriteBuffer = new char[writebuffersize];
124. m_nPortNr = portnr;
125. m_nWriteBufferSize = writebuffersize;
126. m_dwCommEvents = dwCommEvents;
127. BOOL bResult = FALSE;
128. char *szPort = new char[50];
129. char *szBaud = new char[50];
130. // now it critical!
131. EnterCriticalSection(&m_csCommunicationSync);
132. // if the port is already opened: close it
133. if (m_hComm != NULL)
134. {
135. CloseHandle(m_hComm);
136. m_hComm = NULL;
137. }
138. // prepare port strings
139. sprintf(szPort, "COM%d", portnr);
140. // stop is index 0 = 1 1=1.5 2=2
141. int mystop;
142. int myparity;
143. switch(stopbits)
144. {
145. case 0:
146. mystop = ONESTOPBIT;
147. break;
148. case 1:
149. mystop = ONE5STOPBITS;
150. break;
151. case 2:
152. mystop = TWOSTOPBITS;
153. break;
154. }
155. myparity = 0;
156. switch(parity)
157. {
158. case 'N':
159. myparity = 0;
160. break;
161. case 'E':
162. myparity = 1;
163. break;
164. case 'O':
165. myparity = 2;
166. break;
167. case 'M':
168. myparity = 3;
169. break;
170. case 'S':
171. myparity = 4;
172. break;
173. }
174. sprintf(szBaud, "baud=%d parity=%c data=%d stop=%d", baud, parity, databits, mystop);
175. // get a handle to the port
176. m_hComm = CreateFile(szPort,                        // communication port string (COMX)
177. GENERIC_READ | GENERIC_WRITE,  // read/write types
178. 0,                             // comm devices must be opened with exclusive access
179. NULL,                          // no security attributes
180. OPEN_EXISTING,                 // comm devices must use OPEN_EXISTING
181. FILE_FLAG_OVERLAPPED,          // Async I/O
182. 0);                            // template must be 0 for comm devices
183. if (m_hComm == INVALID_HANDLE_VALUE)
184. {
185. // port not found
186. delete [] szPort;
187. delete [] szBaud;
188. return FALSE;
189. }
190. // set the timeout values
191. m_CommTimeouts.ReadIntervalTimeout         = ReadIntervalTimeout * 1000;
192. m_CommTimeouts.ReadTotalTimeoutMultiplier  = ReadTotalTimeoutMultiplier * 1000;
193. m_CommTimeouts.ReadTotalTimeoutConstant    = ReadTotalTimeoutConstant * 1000;
194. m_CommTimeouts.WriteTotalTimeoutMultiplier = WriteTotalTimeoutMultiplier * 1000;
195. m_CommTimeouts.WriteTotalTimeoutConstant   = WriteTotalTimeoutConstant * 1000;
196. // configure
197. if (SetCommTimeouts(m_hComm, &m_CommTimeouts))
198. {
199. if (SetCommMask(m_hComm, dwCommEvents))
200. {
201. if (GetCommState(m_hComm, &m_dcb))
202. {
203. m_dcb.EvtChar = 'q';
204. m_dcb.fRtsControl = RTS_CONTROL_ENABLE;     // set RTS bit high!
205. m_dcb.BaudRate = baud;  // add by mrlong
206. m_dcb.Parity   = myparity;
207. m_dcb.ByteSize = databits;
208. m_dcb.StopBits = mystop;
209. //if (BuildCommDCB(szBaud, &m_dcb))
210. //{
211. if (SetCommState(m_hComm, &m_dcb))
212. ; // normal operation... continue
213. else
214. ProcessErrorMessage("SetCommState()");
215. //}
216. //else
217. //  ProcessErrorMessage("BuildCommDCB()");
218. }
219. else
220. ProcessErrorMessage("GetCommState()");
221. }
222. else
223. ProcessErrorMessage("SetCommMask()");
224. }
225. else
226. ProcessErrorMessage("SetCommTimeouts()");
227. delete [] szPort;
228. delete [] szBaud;
229. // flush the port
230. PurgeComm(m_hComm, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT);
231. // release critical section
232. LeaveCriticalSection(&m_csCommunicationSync);
233. TRACE("Initialisation for communicationport %d completed.\nUse Startmonitor to communicate.\n", portnr);
234. return TRUE;
235. }
236. //
237. //  The CommThread Function.
238. //
239. UINT CSerialPort::CommThread(LPVOID pParam)
240. {
241. // Cast the void pointer passed to the thread back to
242. // a pointer of CSerialPort class
243. CSerialPort *port = (CSerialPort*)pParam;
244. // Set the status variable in the dialog class to
245. // TRUE to indicate the thread is running.
246. port->m_bThreadAlive = TRUE;
247. // Misc. variables
248. DWORD BytesTransfered = 0;
249. DWORD Event = 0;
250. DWORD CommEvent = 0;
251. DWORD dwError = 0;
252. COMSTAT comstat;
253. BOOL  bResult = TRUE;
254. // Clear comm buffers at startup
255. if (port->m_hComm)       // check if the port is opened
256. PurgeComm(port->m_hComm, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT);
257. // begin forever loop.  This loop will run as long as the thread is alive.
258. for (;;)
259. {
260. // Make a call to WaitCommEvent().  This call will return immediatly
261. // because our port was created as an async port (FILE_FLAG_OVERLAPPED
262. // and an m_OverlappedStructerlapped structure specified).  This call will cause the
263. // m_OverlappedStructerlapped element m_OverlappedStruct.hEvent, which is part of the m_hEventArray to
264. // be placed in a non-signeled state if there are no bytes available to be read,
265. // or to a signeled state if there are bytes available.  If this event handle
266. // is set to the non-signeled state, it will be set to signeled when a
267. // character arrives at the port.
268. // we do this for each port!
269. bResult = WaitCommEvent(port->m_hComm, &Event, &port->m_ov);
270. if (!bResult)
271. {
272. // If WaitCommEvent() returns FALSE, process the last error to determin
273. // the reason..
274. switch (dwError = GetLastError())
275. {
276. case ERROR_IO_PENDING:
277. {
278. // This is a normal return value if there are no bytes
279. // to read at the port.
280. // Do nothing and continue
281. break;
282. }
283. case 87:
284. {
285. // Under Windows NT, this value is returned for some reason.
286. // I have not investigated why, but it is also a valid reply
287. // Also do nothing and continue.
288. break;
289. }
290. default:
291. {
292. // All other error codes indicate a serious error has
293. // occured.  Process this error.
294. port->ProcessErrorMessage("WaitCommEvent()");
295. break;
296. }
297. }
298. }
299. else
300. {
301. // If WaitCommEvent() returns TRUE, check to be sure there are
302. // actually bytes in the buffer to read.
303. //
304. // If you are reading more than one byte at a time from the buffer
305. // (which this program does not do) you will have the situation occur
306. // where the first byte to arrive will cause the WaitForMultipleObjects()
307. // function to stop waiting.  The WaitForMultipleObjects() function
308. // resets the event handle in m_OverlappedStruct.hEvent to the non-signelead state
309. // as it returns.
310. //
311. // If in the time between the reset of this event and the call to
312. // ReadFile() more bytes arrive, the m_OverlappedStruct.hEvent handle will be set again
313. // to the signeled state. When the call to ReadFile() occurs, it will
314. // read all of the bytes from the buffer, and the program will
315. // loop back around to WaitCommEvent().
316. //
317. // At this point you will be in the situation where m_OverlappedStruct.hEvent is set,
318. // but there are no bytes available to read.  If you proceed and call
319. // ReadFile(), it will return immediatly due to the async port setup, but
320. // GetOverlappedResults() will not return until the next character arrives.
321. //
322. // It is not desirable for the GetOverlappedResults() function to be in
323. // this state.  The thread shutdown event (event 0) and the WriteFile()
324. // event (Event2) will not work if the thread is blocked by GetOverlappedResults().
325. //
326. // The solution to this is to check the buffer with a call to ClearCommError().
327. // This call will reset the event handle, and if there are no bytes to read
328. // we can loop back through WaitCommEvent() again, then proceed.
329. // If there are really bytes to read, do nothing and proceed.
330. bResult = ClearCommError(port->m_hComm, &dwError, &comstat);
331. if (comstat.cbInQue == 0)
332. continue;
333. }   // end if bResult
334. // Main wait function.  This function will normally block the thread
335. // until one of nine events occur that require action.
336. Event = WaitForMultipleObjects(3, port->m_hEventArray, FALSE, INFINITE);
337. switch (Event)
338. {
339. case 0:
340. {
341. // Shutdown event.  This is event zero so it will be
342. // the higest priority and be serviced first.
343. port->m_bThreadAlive = FALSE;
344. // Kill this thread.  break is not needed, but makes me feel better.
345. AfxEndThread(100);
346. break;
347. }
348. case 1: // read event
349. {
350. GetCommMask(port->m_hComm, &CommEvent);
351. if (CommEvent & EV_RXCHAR) //接收到字符，并置于输入缓冲区中
352. ReceiveChar(port, comstat);
353. if (CommEvent & EV_CTS) //CTS信号状态发生变化
354. ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_CTS_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
355. if (CommEvent & EV_RXFLAG) //接收到事件字符，并置于输入缓冲区中
356. ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_RXFLAG_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
357. if (CommEvent & EV_BREAK)  //输入中发生中断
358. ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_BREAK_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
359. 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
360. ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_ERR_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
361. if (CommEvent & EV_RING) //检测到振铃指示
362. ::SendMessage(port->m_pOwner->m_hWnd, WM_COMM_RING_DETECTED, (WPARAM) 0, (LPARAM) port->m_nPortNr);
363. break;
364. }
365. case 2: // write event
366. {
367. // Write character event from port
368. WriteChar(port);
369. break;
370. }
371. } // end switch
372. } // close forever loop
373. return 0;
374. }
375. //
376. // start comm watching
377. //
378. BOOL CSerialPort::StartMonitoring()
379. {
380. if (!(m_Thread = AfxBeginThread(CommThread, this)))
381. return FALSE;
382. TRACE("Thread started\n");
383. return TRUE;
384. }
385. //
386. // Restart the comm thread
387. //
388. BOOL CSerialPort::RestartMonitoring()
389. {
390. TRACE("Thread resumed\n");
391. m_Thread->ResumeThread();
392. return TRUE;
393. }
394. //
395. // Suspend the comm thread
396. //
397. BOOL CSerialPort::StopMonitoring()
398. {
399. TRACE("Thread suspended\n");
400. m_Thread->SuspendThread();
401. return TRUE;
402. }
403. //
404. // If there is a error, give the right message
405. //
406. void CSerialPort::ProcessErrorMessage(char* ErrorText)
407. {
408. char *Temp = new char[200];
409. LPVOID lpMsgBuf;
410. FormatMessage(
411. FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
412. NULL,
413. GetLastError(),
414. MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
415. (LPTSTR) &lpMsgBuf,
416. 0,
417. NULL
418. );
419. sprintf(Temp, "WARNING:  %s Failed with the following error: \n%s\nPort: %d\n", (char*)ErrorText, lpMsgBuf, m_nPortNr);
420. MessageBox(NULL, Temp, "Application Error", MB_ICONSTOP);
421. LocalFree(lpMsgBuf);
422. delete[] Temp;
423. }
424. //
425. // Write a character.
426. //
427. void CSerialPort::WriteChar(CSerialPort* port)
428. {
429. BOOL bWrite = TRUE;
430. BOOL bResult = TRUE;
431. DWORD BytesSent = 0;
432. DWORD SendLen   = port->m_nWriteSize;
433. ResetEvent(port->m_hWriteEvent);
434. // Gain ownership of the critical section
435. EnterCriticalSection(&port->m_csCommunicationSync);
436. if (bWrite)
437. {
438. // Initailize variables
439. port->m_ov.Offset = 0;
440. port->m_ov.OffsetHigh = 0;
441. // Clear buffer
442. PurgeComm(port->m_hComm, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT);
443. bResult = WriteFile(port->m_hComm,                           // Handle to COMM Port
444. port->m_szWriteBuffer,                   // Pointer to message buffer in calling finction
445. SendLen,    // add by mrlong
446. //strlen((char*)port->m_szWriteBuffer),  // Length of message to send
447. &BytesSent,                             // Where to store the number of bytes sent
448. &port->m_ov);                            // Overlapped structure
449. // deal with any error codes
450. if (!bResult)
451. {
452. DWORD dwError = GetLastError();
453. switch (dwError)
454. {
455. case ERROR_IO_PENDING:
456. {
457. // continue to GetOverlappedResults()
458. BytesSent = 0;
459. bWrite = FALSE;
460. break;
461. }
462. default:
463. {
464. // all other error codes
465. port->ProcessErrorMessage("WriteFile()");
466. }
467. }
468. }
469. else
470. {
471. LeaveCriticalSection(&port->m_csCommunicationSync);
472. }
473. } // end if(bWrite)
474. if (!bWrite)
475. {
476. bWrite = TRUE;
477. bResult = GetOverlappedResult(port->m_hComm, // Handle to COMM port
478. &port->m_ov,       // Overlapped structure
479. &BytesSent,       // Stores number of bytes sent
480. TRUE);            // Wait flag
481. LeaveCriticalSection(&port->m_csCommunicationSync);
482. // deal with the error code
483. if (!bResult)
484. {
485. port->ProcessErrorMessage("GetOverlappedResults() in WriteFile()");
486. }
487. } // end if (!bWrite)
488. // Verify that the data size send equals what we tried to send
489. if (BytesSent != SendLen /*strlen((char*)port->m_szWriteBuffer)*/)  // add by
490. {
491. TRACE("WARNING: WriteFile() error.. Bytes Sent: %d; Message Length: %d\n", BytesSent, strlen((char*)port->m_szWriteBuffer));
492. }
493. }
494. //
495. // Character received. Inform the owner
496. //
497. void CSerialPort::ReceiveChar(CSerialPort* port, COMSTAT comstat)
498. {
499. BOOL  bRead = TRUE;
500. BOOL  bResult = TRUE;
501. DWORD dwError = 0;
502. DWORD BytesRead = 0;
503. unsigned char RXBuff;
504. for (;;)
505. {
506. //add by liquanhai 2011-11-06  防止死锁
507. if(WaitForSingleObject(port->m_hShutdownEvent,0)==WAIT_OBJECT_0)
508. return;
509. // Gain ownership of the comm port critical section.
510. // This process guarantees no other part of this program
511. // is using the port object.
512. EnterCriticalSection(&port->m_csCommunicationSync);
513. // ClearCommError() will update the COMSTAT structure and
514. // clear any other errors.
515. bResult = ClearCommError(port->m_hComm, &dwError, &comstat);
516. LeaveCriticalSection(&port->m_csCommunicationSync);
517. // start forever loop.  I use this type of loop because I
518. // do not know at runtime how many loops this will have to
519. // run. My solution is to start a forever loop and to
520. // break out of it when I have processed all of the
521. // data available.  Be careful with this approach and
522. // be sure your loop will exit.
523. // My reasons for this are not as clear in this sample
524. // as it is in my production code, but I have found this
525. // solutiion to be the most efficient way to do this.
526. if (comstat.cbInQue == 0)
527. {
528. // break out when all bytes have been read
529. break;
530. }
531. EnterCriticalSection(&port->m_csCommunicationSync);
532. if (bRead)
533. {
534. bResult = ReadFile(port->m_hComm,        // Handle to COMM port
535. &RXBuff,             // RX Buffer Pointer
536. 1,                   // Read one byte
537. &BytesRead,          // Stores number of bytes read
538. &port->m_ov);     // pointer to the m_ov structure
539. // deal with the error code
540. if (!bResult)
541. {
542. switch (dwError = GetLastError())
543. {
544. case ERROR_IO_PENDING:
545. {
546. // asynchronous i/o is still in progress
547. // Proceed on to GetOverlappedResults();
548. bRead = FALSE;
549. break;
550. }
551. default:
552. {
553. // Another error has occured.  Process this error.
554. port->ProcessErrorMessage("ReadFile()");
555. break;
556. }
557. }
558. }
559. else
560. {
561. // ReadFile() returned complete. It is not necessary to call GetOverlappedResults()
562. bRead = TRUE;
563. }
564. }  // close if (bRead)
565. if (!bRead)
566. {
567. bRead = TRUE;
568. bResult = GetOverlappedResult(port->m_hComm, // Handle to COMM port
569. &port->m_ov,       // Overlapped structure
570. &BytesRead,       // Stores number of bytes read
571. TRUE);            // Wait flag
572. // deal with the error code
573. if (!bResult)
574. {
575. port->ProcessErrorMessage("GetOverlappedResults() in ReadFile()");
576. }
577. }  // close if (!bRead)
578. LeaveCriticalSection(&port->m_csCommunicationSync);
579. // notify parent that a byte was received
580. ::SendMessage((port->m_pOwner)->m_hWnd, WM_COMM_RXCHAR, (WPARAM) RXBuff, (LPARAM) port->m_nPortNr);
581. } // end forever loop
582. }
583. //
584. // Write a string to the port
585. //
586. void CSerialPort::WriteToPort(char* string)
587. {
588. assert(m_hComm != 0);
589. memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
590. strcpy(m_szWriteBuffer, string);
591. m_nWriteSize=strlen(string); // add by mrlong
592. // set event for write
593. SetEvent(m_hWriteEvent);
594. }
595. //
596. // Return the device control block
597. //
598. DCB CSerialPort::GetDCB()
599. {
600. return m_dcb;
601. }
602. //
603. // Return the communication event masks
604. //
605. DWORD CSerialPort::GetCommEvents()
606. {
607. return m_dwCommEvents;
608. }
609. //
610. // Return the output buffer size
611. //
612. DWORD CSerialPort::GetWriteBufferSize()
613. {
614. return m_nWriteBufferSize;
615. }
616. void CSerialPort::ClosePort()
617. {

/*
**	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\n");
 
	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\n");
	}
 
	// 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.\nUse Startmonitor to communicate.\n", 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\n");
	return TRUE;
}
 
//
// Restart the comm thread
//
BOOL CSerialPort::RestartMonitoring()
{
	TRACE("Thread resumed\n");
	m_Thread->ResumeThread();
	return TRUE;
}
 
//
// Suspend the comm thread
//
BOOL CSerialPort::StopMonitoring()
{
	TRACE("Thread suspended\n");
	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: \n%s\nPort: %d\n", (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\n", 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()
{

1. MSG message;
2. do
3. {
4. SetEvent(m_hShutdownEvent);
5. if(::PeekMessage(&message,m_pOwner->m_hWnd,0,0,PM_REMOVE))
6. {
7. ::TranslateMessage(&message);
8. ::DispatchMessage(&message);
9. }
10. } while (m_bThreadAlive);
11. // if the port is still opened: close it
12. if (m_hComm != NULL)
13. {
14. CloseHandle(m_hComm);
15. m_hComm = NULL;
16. }
17. // Close Handles
18. if(m_hShutdownEvent!=NULL)
19. ResetEvent(m_hShutdownEvent);
20. if(m_ov.hEvent!=NULL)
21. ResetEvent(m_ov.hEvent);
22. if(m_hWriteEvent!=NULL)
23. ResetEvent(m_hWriteEvent);
24. //delete [] m_szWriteBuffer;
25. }
26. void CSerialPort::WriteToPort(char* string,int n)
27. {
28. assert(m_hComm != 0);
29. memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
30. memcpy(m_szWriteBuffer, string, n);
31. m_nWriteSize = n;
32. // set event for write
33. SetEvent(m_hWriteEvent);
34. }
35. void CSerialPort::WriteToPort(LPCTSTR string)
36. {
37. assert(m_hComm != 0);
38. memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
39. strcpy(m_szWriteBuffer, string);
40. m_nWriteSize=strlen(string);
41. // set event for write
42. SetEvent(m_hWriteEvent);
43. }
44. void CSerialPort::WriteToPort(BYTE* Buffer, int n)
45. {
46. assert(m_hComm != 0);
47. memset(m_szWriteBuffer, 0, sizeof(m_szWriteBuffer));
48. int i;
49. for(i=0; i<n; i++)
50. {
51. m_szWriteBuffer[i] = Buffer[i];
52. }
53. m_nWriteSize=n;
54. // set event for write
55. SetEvent(m_hWriteEvent);
56. }
57. void CSerialPort::SendData(LPCTSTR lpszData, const int nLength)
58. {
59. assert(m_hComm != 0);
60. memset(m_szWriteBuffer, 0, nLength);
61. strcpy(m_szWriteBuffer, lpszData);
62. m_nWriteSize=nLength;
63. // set event for write
64. SetEvent(m_hWriteEvent);
65. }
66. BOOL CSerialPort::RecvData(LPTSTR lpszData, const int nSize)
67. {
68. //
69. //接收数据
70. //
71. assert(m_hComm!=0);
72. memset(lpszData,0,nSize);
73. DWORD mylen  = 0;
74. DWORD mylen2 = 0;
75. while (mylen<nSize) {
76. if(!ReadFile(m_hComm,lpszData,nSize,&mylen2,NULL))
77. return FALSE;
78. mylen += mylen2;
79. }
80. return TRUE;
81. }

        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