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这是一份优秀的串口类文件,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。
2016-05-07补充说明:
CSerialPort类地址:https://github.com/itas109/CSerialPort
CSDN下载:http://download.csdn.net/detail/itas109/9512828
更新内容:
- 修复每次打开串口发送一次,当串口无应答时,需要关闭再打开或者接收完数据才能发送的问题。 解决办法:在m_hEventArray中调整m_hWriteEvent的优先级高于读的优先级。CommThread(LPVOID pParam)函数中读写的位置也调换。 参考:http://zhidao.baidu.com/link?url=RSrbPcfTZRULFFd2ziHZPBwnoXv1iCSu_Nmycb_yEw1mklT8gkoNZAkWpl3UDhk8L35DtRPo5VV5kEGpOx-Gea
- 修复停止位在头文件中定义成1导致SetCommState报错的问题,应为1对应的停止位是1.5。UINT stopsbits = ONESTOPBIT
- switch(stopbits)和switch(parity)增加默认情况,增强程序健壮性
历史更新:
First Version by Remon Spekreijse on 2000-02-08
Second Version by mrlong on 2007-12-25
https://code.google.com/p/mycom/
* 增加 ClosePort
* 增加 WriteToPort 两个方法
* 增加 SendData 与 RecvData 方法
by liquanhai on 2011-11-04
http://blog.csdn.net/liquanhai/article/details/4955253
* 增加 ClosePort 中交出控制权,防止死锁问题
by liquanhai on 2011-11-06
http://blog.csdn.net/liquanhai/article/details/6941574
* 增加 ReceiveChar 中防止线程死锁
by viruscamp on 2013-12-04
https://github.com/viruscamp/CSerialPort
* 增加 IsOpen 判断是否打开
* 修正 InitPort 中 parity Odd Even 参数取值错误
* 修改 InitPort 中 portnr 取值范围,portnr>9 时特殊处理
* 取消对 MFC 的依赖,使用 HWND 替代 CWnd,使用 win32 thread 函数而不是 MFC 的
* 增加用户消息编号自定义,方法来自 CnComm
by itas109 on 2014-01-10
http://blog.csdn.net/itas109/article/details/18358297
* 解决COM10以上端口无法显示的问题
* 扩展可选择端口,最大值MaxSerialPortNum可以自定义
* 添加QueryKey()和Hkey2ComboBox两个方法,用于自动查询当前有效的串口号。
by liquanhai on 2014-12-18
* 增加一些处理措施,主要是对减少CPU占用率
/* ** 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 WriteToPort 两个方法 ** 3) 增加 SendData 与 RecvData 方法 ************************************************************************************** *************************************************************************************** ** author:liquanhai date:2011-11-06 ** ** 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 ************************************************************************************** *************************************************************************************** ** author:viruscamp date:2013-12-04 ** ** 改进 ** 1) 增加 IsOpen 判断是否打开 ** 2) 修正 InitPort 中 parity Odd Even 参数取值错误 ** 3) 修改 InitPort 中 portnr 取值范围,portnr>9 时特殊处理 ** 4) 取消对 MFC 的依赖,使用 HWND 替代 CWnd,使用 win32 thread 函数而不是 MFC 的 ** 5) 增加用户消息编号自定义,方法来自 CnComm *************************************************************************************** *************************************************************************************** ** author: itas109 date:2014-01-10 ** Blog:blog.csdn.net/itas109 ** ** 改进 ** 1) 解决COM10以上端口无法显示的问题 ** 2) 扩展可选择端口,最大值MaxSerialPortNum可以自定义 ** 3) 添加QueryKey()和Hkey2ComboBox两个方法,用于自动查询当前有效的串口号。 *************************************************************************************** ** author: itas109 date:2016-05-06 ** Blog:blog.csdn.net/itas109 ** ** 改进 ** 1) 修复每次打开串口发送一次,当串口无应答时,需要关闭再打开或者接收完数据才能发送的问题。 ** 解决办法:在m_hEventArray中调整m_hWriteEvent的优先级高于读的优先级。CommThread(LPVOID pParam)函数中读写的位置也调换。 ** 参考:http://zhidao.baidu.com/link?url=RSrbPcfTZRULFFd2ziHZPBwnoXv1iCSu_Nmycb_yEw1mklT8gkoNZAkWpl3UDhk8L35DtRPo5VV5kEGpOx-Gea ** 2) 修复停止位在头文件中定义成1导致SetCommState报错的问题,应为1对应的停止位是1.5。UINT stopsbits = ONESTOPBIT ** 3) switch(stopbits)和switch(parity)增加默认情况,增强程序健壮性 ** */ #ifndef __SERIALPORT_H__ #define __SERIALPORT_H__ #ifndef WM_COMM_MSG_BASE #define WM_COMM_MSG_BASE WM_USER + 617 //!< 消息编号的基点 #endif #define WM_COMM_BREAK_DETECTED WM_COMM_MSG_BASE + 1 // A break was detected on input. #define WM_COMM_CTS_DETECTED WM_COMM_MSG_BASE + 2 // The CTS (clear-to-send) signal changed state. #define WM_COMM_DSR_DETECTED WM_COMM_MSG_BASE + 3 // The DSR (data-set-ready) signal changed state. #define WM_COMM_ERR_DETECTED WM_COMM_MSG_BASE + 4 // A line-status error occurred. Line-status errors are CE_FRAME, CE_OVERRUN, and CE_RXPARITY. #define WM_COMM_RING_DETECTED WM_COMM_MSG_BASE + 5 // A ring indicator was detected. #define WM_COMM_RLSD_DETECTED WM_COMM_MSG_BASE + 6 // The RLSD (receive-line-signal-detect) signal changed state. #define WM_COMM_RXCHAR WM_COMM_MSG_BASE + 7 // A character was received and placed in the input buffer. #define WM_COMM_RXFLAG_DETECTED WM_COMM_MSG_BASE + 8 // The event character was received and placed in the input buffer. #define WM_COMM_TXEMPTY_DETECTED WM_COMM_MSG_BASE + 9 // The last character in the output buffer was sent. #define MaxSerialPortNum 20 ///有效的串口总个数,不是串口的号 //add by itas109 2014-01-09 class CSerialPort { public: // contruction and destruction CSerialPort(); virtual ~CSerialPort(); // port initialisation // UINT stopsbits = ONESTOPBIT stop is index 0 = 1 1=1.5 2=2 // 切记:stopsbits = 1,不是停止位为1。 // by itas109 20160506 BOOL InitPort(CWnd* pPortOwner, UINT portnr = 1, UINT baud = 19200, char parity = 'N', UINT databits = 8, UINT stopsbits = ONESTOPBIT, 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 ///控制串口监视线程 BOOL StartMonitoring();//开始监听 BOOL RestartMonitoring();//重新监听 BOOL StopMonitoring();//停止监听 DWORD GetWriteBufferSize();///获取写缓冲大小 DWORD GetCommEvents();///获取事件 DCB GetDCB();///获取DCB ///写数据到串口 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(LPCTSTR string,int n);//add by mrlong 2007-12-2 void WriteToPort(BYTE* Buffer, int n);// add by mrlong void ClosePort(); // add by mrlong 2007-12-2 BOOL IsOpen(); 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 void QueryKey(HKEY hKey);///查询注册表的串口号,将值存于数组中 void Hkey2ComboBox(CComboBox& m_PortNO);///将QueryKey查询到的串口号添加到CComboBox控件中 protected: // protected memberfunctions void ProcessErrorMessage(char* ErrorText);///错误处理 static DWORD WINAPI CommThread(LPVOID pParam);///线程函数 static void ReceiveChar(CSerialPort* port); static void WriteChar(CSerialPort* port); // thread //CWinThread* m_Thread; HANDLE m_Thread; BOOL m_bIsSuspened;///thread监视线程是否挂起 // synchronisation objects CRITICAL_SECTION m_csCommunicationSync;///临界资源 BOOL m_bThreadAlive;///监视线程运行标志 // handles HANDLE m_hShutdownEvent; //stop发生的事件 HANDLE m_hComm; // 串口句柄 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. ///事件数组,包括一个写事件,接收事件,关闭事件 ///一个元素用于一个事件。有两个事件线程处理端口。 ///写事件和接收字符事件位于overlapped结构体(m_ov.hEvent)中 ///当端口关闭时,有一个通用的关闭。 HANDLE m_hEventArray[3]; // structures OVERLAPPED m_ov;///异步I/O COMMTIMEOUTS m_CommTimeouts;///超时设置 DCB m_dcb;///设备控制块 // owner window CWnd* m_pOwner; //HWND m_pOwner; // misc UINT m_nPortNr; //????? char* m_szWriteBuffer;///写缓冲区 DWORD m_dwCommEvents; DWORD m_nWriteBufferSize;///写缓冲大小 int m_nWriteSize;//写入字节数 //add by mrlong 2007-12-25 }; #endif __SERIALPORT_H__
/* ** 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 ** ** 2007-12-25 mrlong https://code.google.com/p/mycom/ ** 2011-11-06 liquanhai http://blog.csdn.net/liquanhai/article/details/6941574 ** 2013-12-04 viruscamp https://github.com/viruscamp/CSerialPort ** 2014-01-10 itas109 http://blog.csdn.net/itas109 ** 2014-12-18 liquanhai http://blog.csdn.net/liquanhai/article/details/6941574 ** 2016-05-06 itas109 http://blog.csdn.net/itas109 */ #include "stdafx.h" #include "SerialPort.h" #include <assert.h> int m_nComArray[20]; // // Constructor // CSerialPort::CSerialPort() { m_hComm = NULL; // initialize overlapped structure members to zero ///初始化异步结构体 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; m_bIsSuspened = FALSE; } // // Delete dynamic memory // CSerialPort::~CSerialPort() { do { SetEvent(m_hShutdownEvent); } 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) 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 MaxSerialPortNum. ///初始化串口。只能是1-MaxSerialPortNum // //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..MaxSerialPortNum) 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 < 200); 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 ///事件数组初始化,设定优先级别 m_hEventArray[0] = m_hShutdownEvent; // highest priority m_hEventArray[1] = m_hWriteEvent; m_hEventArray[2] = m_ov.hEvent; // initialize critical section ///初始化临界资源 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]; /* 多个线程操作相同的数据时,一般是需要按顺序访问的,否则会引导数据错乱, 无法控制数据,变成随机变量。为解决这个问题,就需要引入互斥变量,让每 个线程都按顺序地访问变量。这样就需要使用EnterCriticalSection和 LeaveCriticalSection函数。 */ // now it critical! EnterCriticalSection(&m_csCommunicationSync); // if the port is already opened: close it ///串口已打开就关掉 if (m_hComm != NULL) { CloseHandle(m_hComm); m_hComm = NULL; } // prepare port strings sprintf(szPort, "\\\\.\\COM%d", portnr);///可以显示COM10以上端口//add by itas109 2014-01-09 // 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; //增加默认情况,因为stopbits=1.5时,SetCommState会报错。 //一般的电脑串口不支持1.5停止位,这个1.5停止位似乎用在红外传输上的。 //by itas109 20160506 default: mystop = ONESTOPBIT; break; } myparity = 0; parity = toupper(parity); switch(parity) { case 'N': myparity = 0; break; case 'O': myparity = 1; break; case 'E': myparity = 2; break; case 'M': myparity = 3; break; case 'S': myparity = 4; break; //增加默认情况。 //by itas109 20160506 default: myparity = 0; break; } sprintf(szBaud, "baud=%d parity=%c data=%d stop=%d", baud, parity, databits, mystop); // get a handle to the port /* 通信程序在CreateFile处指定串口设备及相关的操作属性,再返回一个句柄, 该句柄将被用于后续的通信操作,并贯穿整个通信过程串口打开后,其属性 被设置为默认值,根据具体需要,通过调用GetCommState(hComm,&&dcb)读取 当前串口设备控制块DCB设置,修改后通过SetCommState(hComm,&&dcb)将其写 入。运用ReadFile()与WriteFile()这两个API函数实现串口读写操作,若为异 步通信方式,两函数中最后一个参数为指向OVERLAPPED结构的非空指针,在读 写函数返回值为FALSE的情况下,调用GetLastError()函数,返回值为ERROR_IO_PENDING, 表明I/O操作悬挂,即操作转入后台继续执行。此时,可以用WaitForSingleObject() 来等待结束信号并设置最长等待时间 */ 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 ///创建失败 if (m_hComm == INVALID_HANDLE_VALUE) { // port not found delete [] szPort; delete [] szBaud; return FALSE; } // set the timeout values ///设置超时 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 ///配置 ///分别调用Windows API设置串口参数 if (SetCommTimeouts(m_hComm, &m_CommTimeouts))///设置超时 { /* 若对端口数据的响应时间要求较严格,可采用事件驱动方式。 事件驱动方式通过设置事件通知,当所希望的事件发生时,Windows 发出该事件已发生的通知,这与DOS环境下的中断方式很相似。Windows 定义了9种串口通信事件,较常用的有以下三种: EV_RXCHAR:接收到一个字节,并放入输入缓冲区; EV_TXEMPTY:输出缓冲区中的最后一个字符,发送出去; EV_RXFLAG:接收到事件字符(DCB结构中EvtChar成员),放入输入缓冲区 在用SetCommMask()指定了有用的事件后,应用程序可调用WaitCommEvent()来等待事 件的发生。SetCommMask(hComm,0)可使WaitCommEvent()中止 */ if (SetCommMask(m_hComm, dwCommEvents))///设置通信事件 { if (GetCommState(m_hComm, &m_dcb))///获取当前DCB参数 { 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))///填写DCB结构 //{ if (SetCommState(m_hComm, &m_dcb))///配置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 ///终止读写并清空接收和发送 PurgeComm(m_hComm, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT | PURGE_TXABORT); // release critical section ///释放临界资源 LeaveCriticalSection(&m_csCommunicationSync); //TRACE("Initialisation for communicationport %d completed.\nUse Startmonitor to communicate.\n", portnr); return TRUE; } // // The CommThread Function. ///线程函数 ///监视线程的大致流程: ///检查串口-->进入循环{WaitCommEvent(不阻塞询问)询问事件-->如果有事件来到-->到相应处理(关闭\读\写)} // DWORD WINAPI 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. ///TRUE表示线程正在运行 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 ///开始时清除串口缓冲 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. ///只要线程存在就不断读取数据 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! /* WaitCommEvent函数第3个参数1pOverlapped可以是一个OVERLAPPED结构的变量指针 ,也可以是NULL,当用NULL时,表示该函数是同步的,否则表示该函数是异步的。 调用WaitCommEvent时,如果异步操作不能立即完成,会立即返回FALSE,系统在 WaitCommEvent返回前将OVERLAPPED结构成员hEvent设为无信号状态,等到产生通信 事件时,系统将其置有信号 */ bResult = WaitCommEvent(port->m_hComm, &Event, &port->m_ov);///表示该函数是异步的 if (!bResult) { // If WaitCommEvent() returns FALSE, process the last error to determin // the reason.. ///如果WaitCommEvent返回Error为FALSE,则查询错误信息 switch (dwError = GetLastError()) { case ERROR_IO_PENDING: ///正常情况,没有字符可读 { // This is a normal return value if there are no bytes // to read at the port. // Do nothing and continue break; } case 87:///系统错误 { // 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:///发生其他错误,其中有串口读写中断开串口连接的错误 { // All other error codes indicate a serious error has // occured. Process this error. port->ProcessErrorMessage("WaitCommEvent()"); break; } } } else ///WaitCommEvent()能正确返回 { // 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 ///主等待函数,会阻塞线程 // Main wait function. This function will normally block the thread // until one of nine events occur that require action. ///等待3个事件:关断/读/写,有一个事件发生就返回 Event = WaitForMultipleObjects(3, ///3个事件 port->m_hEventArray, ///事件数组 FALSE, ///有一个事件发生就返回 INFINITE);///超时时间 switch (Event) { case 0: { // Shutdown event. This is event zero so it will be // the higest priority and be serviced first. ///关断事件,关闭串口 CloseHandle(port->m_hComm); port->m_hComm=NULL; port->m_bThreadAlive = FALSE; // Kill this thread. break is not needed, but makes me feel better. //AfxEndThread(100); ::ExitThread(100); break; } case 2: // read event 将定义的各种消息发送出去 { 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); 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 1: // write event 发送数据 { // Write character event from port WriteChar(port); break; } default: { AfxMessageBox("接收有问题!"); break; } } // end switch } // close forever loop return 0; } // // start comm watching ///开启监视线程 // BOOL CSerialPort::StartMonitoring() { //if (!(m_Thread = AfxBeginThread(CommThread, this))) if (!(m_Thread = ::CreateThread (NULL, 0, CommThread, this, 0, NULL ))) return FALSE; //TRACE("Thread started\n"); return TRUE; } // // Restart the comm thread ///复位监视线程 // BOOL CSerialPort::RestartMonitoring() { //TRACE("Thread resumed\n"); //m_Thread->ResumeThread(); ::ResumeThread(m_Thread); return TRUE; } // // Suspend the comm thread ///挂起监视线程 // BOOL CSerialPort::StopMonitoring() { //TRACE("Thread suspended\n"); //m_Thread->SuspendThread(); ::SuspendThread(m_Thread); return TRUE; } // // If there is a error, give the right message ///如果有错误,给出提示 // 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) { BOOL bRead = TRUE; BOOL bResult = TRUE; DWORD dwError = 0; DWORD BytesRead = 0; COMSTAT comstat; 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. ///更新COMSTAT 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. ///所有字符均被读出,中断循环 if (comstat.cbInQue == 0) { // break out when all bytes have been read break; } EnterCriticalSection(&port->m_csCommunicationSync); if (bRead) { ///串口读出,读出缓冲区中字节 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 ///若返回错误,错误处理 if (!bResult) { switch (dwError = GetLastError()) { case ERROR_IO_PENDING: { // asynchronous i/o is still in progress // Proceed on to GetOverlappedResults(); ///异步IO仍在进行 bRead = FALSE; break; } default: { // Another error has occured. Process this error. port->ProcessErrorMessage("ReadFile()"); break; //return;///防止读写数据时,串口非正常断开导致死循环一直执行。add by itas109 2014-01-09 与上面liquanhai添加防死锁的代码差不多 } } } else///ReadFile返回TRUE { // ReadFile() returned complete. It is not necessary to call GetOverlappedResults() bRead = TRUE; } } // close if (bRead) ///异步IO操作仍在进行,需要调用GetOverlappedResult查询 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; } BOOL CSerialPort::IsOpen() { return m_hComm != NULL; } void CSerialPort::ClosePort() { MSG message; //add by liquanhai 防止死锁 2011-11-06 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; if(m_szWriteBuffer != NULL) { delete [] m_szWriteBuffer; m_szWriteBuffer = NULL; } } 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; } // ///查询注册表的串口号,将值存于数组中 ///本代码参考于mingojiang的获取串口逻辑名代码 // void CSerialPort::QueryKey(HKEY hKey) { #define MAX_KEY_LENGTH 255 #define MAX_VALUE_NAME 16383 // TCHAR achKey[MAX_KEY_LENGTH]; // buffer for subkey name // DWORD cbName; // size of name string TCHAR achClass[MAX_PATH] = TEXT(""); // buffer for class name DWORD cchClassName = MAX_PATH; // size of class string DWORD cSubKeys=0; // number of subkeys DWORD cbMaxSubKey; // longest subkey size DWORD cchMaxClass; // longest class string DWORD cValues; // number of values for key DWORD cchMaxValue; // longest value name DWORD cbMaxValueData; // longest value data DWORD cbSecurityDescriptor; // size of security descriptor FILETIME ftLastWriteTime; // last write time DWORD i, retCode; TCHAR achValue[MAX_VALUE_NAME]; DWORD cchValue = MAX_VALUE_NAME; // Get the class name and the value count. retCode = RegQueryInfoKey( hKey, // key handle achClass, // buffer for class name &cchClassName, // size of class string NULL, // reserved &cSubKeys, // number of subkeys &cbMaxSubKey, // longest subkey size &cchMaxClass, // longest class string &cValues, // number of values for this key &cchMaxValue, // longest value name &cbMaxValueData, // longest value data &cbSecurityDescriptor, // security descriptor &ftLastWriteTime); // last write time for (i=0;i<20;i++)///存放串口号的数组初始化 { m_nComArray[i] = -1; } // Enumerate the key values. if (cValues > 0) { for (i=0, retCode=ERROR_SUCCESS; i<cValues; i++) { cchValue = MAX_VALUE_NAME; achValue[0] = '\0'; if (ERROR_SUCCESS == RegEnumValue(hKey, i, achValue, &cchValue, NULL, NULL, NULL, NULL)) { CString szName(achValue); if (-1 != szName.Find(_T("Serial")) || -1 != szName.Find(_T("VCom")) ){ BYTE strDSName[10]; memset(strDSName, 0, 10); DWORD nValueType = 0, nBuffLen = 10; if (ERROR_SUCCESS == RegQueryValueEx(hKey, (LPCTSTR)achValue, NULL, &nValueType, strDSName, &nBuffLen)){ int nIndex = -1; while(++nIndex < MaxSerialPortNum){ if (-1 == m_nComArray[nIndex]) { m_nComArray[nIndex] = atoi((char*)(strDSName + 3)); break; } } } } } } } else{ AfxMessageBox(_T("本机没有串口.....")); } } void CSerialPort::Hkey2ComboBox(CComboBox& m_PortNO) { HKEY hTestKey; bool Flag = FALSE; ///仅是XP系统的注册表位置,其他系统根据实际情况做修改 if(ERROR_SUCCESS == RegOpenKeyEx(HKEY_LOCAL_MACHINE, TEXT("HARDWARE\\DEVICEMAP\\SERIALCOMM"), 0, KEY_READ, &hTestKey) ){ QueryKey(hTestKey); } RegCloseKey(hTestKey); int i = 0; m_PortNO.ResetContent();///刷新时,清空下拉列表内容 while(i < MaxSerialPortNum && -1 != m_nComArray[i]){ CString szCom; szCom.Format(_T("COM%d"), m_nComArray[i]); m_PortNO.InsertString(i, szCom.GetBuffer(5)); ++i; Flag = TRUE; if (Flag)///把第一个发现的串口设为下拉列表的默认值 m_PortNO.SetCurSel(0); } }
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