一个很不错的串口通讯及实例程序

//////////////////////////////////////////////////////////////////////////////////////// // // Project: Class ComAccess // Overlapped serial IO communication class // System: Win9x WinNT // File: comaccess.cpp // Start date: 17.11.1997 // Update: 31.07.1998 // Version: 1.2 // Author: Patrick Feuser pat@das-netz.de Germany // Copyright � 1997. Alle Rechte vorbehalten // //////////////////////////////////////////////////////////////////////////////////////// #include "comaccess.h" //////////////////////////////////////////////////////////////////////////////////////// // // Constructors // ComAccess::ComAccess(VOID) { m_hCom = 0; m_lpszErrorMessage[0] = '\0'; ZeroMemory(&m_ov, sizeof(m_ov)); } ComAccess::ComAccess(LPCSTR lpszPortNum) { ComAccess::ComAccess(); ComAccess::Open(lpszPortNum); } //////////////////////////////////////////////////////////////////////////////////////// // // Function: Open(LPCSTR lpszPortNum, // DWORD dwBaudRate, // BYTE byParity, // BYTE byStopBits, // BYTE byByteSize) // // Return value: BOOL TRUE or FALSE // BOOL ComAccess::Open(LPCSTR lpszPortNum, DWORD dwBaudRate, BYTE byParity, BYTE byStopBits, BYTE byByteSize) { DCB dcb; // structure that defines the control setting for a serial communications device BOOL bSuccess; m_hCom = CreateFile(lpszPortNum, // pointer to name of the file GENERIC_READ|GENERIC_WRITE, // access mode 0, // comm devices must be opened w/exclusive-access NULL, // no security attributs OPEN_EXISTING, // comm devices must use OPEN_EXISTING FILE_FLAG_OVERLAPPED, // overlapped I/O NULL); // hTemplate must be NULL for comm devices if ( m_hCom == INVALID_HANDLE_VALUE ) { // handle the error ComAccess::ErrorToString("Open(): CreateFile() failed, invalid handle value"); return FALSE; } // // Omit the call to SetupComm to use the default queue sizes. // Get the current configuration. // bSuccess = GetCommState(m_hCom, &dcb); if ( ! bSuccess ) { // Handle the error. ComAccess::ErrorToString("Open(): GetCommState() failed"); ComAccess::Close(); return FALSE; } // // Fill in the DCB: baud=9600, 8 data bits, no parity, 1 stop bit are default parameters // dcb.BaudRate = dwBaudRate; dcb.ByteSize = byByteSize; dcb.Parity = byParity; dcb.StopBits = byStopBits; bSuccess = SetCommState(m_hCom, &dcb); if ( ! bSuccess ) { // Handle the error. ComAccess::ErrorToString("Open(): SetCommState() failed"); ComAccess::Close(); return FALSE; } return TRUE; } //////////////////////////////////////////////////////////////////////////////////////// // // Function: Close(VOID) // // Return value: VOID // VOID ComAccess::Close(VOID) { if ( m_hCom > 0 ) { CloseHandle(m_hCom); } m_hCom = 0; } //////////////////////////////////////////////////////////////////////////////////////// // // Function: WriteData(LPCVOID pdata, // DWORD len) // // Return value: DWORD -1 failed, above, num written bytes // DWORD ComAccess::WriteData(LPCVOID pdata, DWORD len) { BOOL bSuccess; DWORD written = 0; if ( len < 1 ) return(0); // create event for overlapped I/O m_ov.hEvent = CreateEvent(NULL, // pointer to security attributes FALSE, // flag for manual-reset event FALSE, // flag for initial state ""); // pointer to event-object name if ( m_ov.hEvent == INVALID_HANDLE_VALUE ) { // Handle the error. ComAccess::ErrorToString("WriteData(): CreateEvent() failed"); return(-1); } bSuccess = WriteFile(m_hCom, // handle to file to write to pdata, // pointer to data to write to file len, // number of bytes to write &written, // pointer to number of bytes written &m_ov); // pointer to structure needed for overlapped I/O if ( ComAccess::IsNT() ) { bSuccess = GetOverlappedResult(m_hCom, &m_ov, &written, TRUE); if ( ! bSuccess ) { // Handle the error. CloseHandle(m_ov.hEvent); ComAccess::ErrorToString("WriteData(): GetOverlappedResult() failed"); return(-1); } } else if ( len != written ) { // Handle the error. CloseHandle(m_ov.hEvent); ComAccess::ErrorToString("WriteData(): WriteFile() failed"); return(-1); } CloseHandle(m_ov.hEvent); return written; } //////////////////////////////////////////////////////////////////////////////////////// // // Function: ReadData(LPVOID pdest, // DWORD len, // DWORD dwMaxWait) // // Return value: DWORD -1 failed, above, num read bytes // DWORD ComAccess::ReadData(LPVOID pdest, DWORD len, DWORD dwMaxWait) { BOOL bSuccess; DWORD result = 0, read = 0, // num read bytes mask = 0; // a 32-bit variable that receives a mask // indicating the type of event that occurred if ( len < 1 ) return(0); // create event for overlapped I/O m_ov.hEvent = CreateEvent(NULL, // pointer to security attributes FALSE, // flag for manual-reset event FALSE, // flag for initial state ""); // pointer to event-object name if ( m_ov.hEvent == INVALID_HANDLE_VALUE ) { // Handle the error. ComAccess::ErrorToString("ReadData(): CreateEvent() failed"); return(-1); } // Specify here the event to be enabled bSuccess = SetCommMask(m_hCom, EV_RXCHAR); if ( ! bSuccess ) { // Handle the error. CloseHandle(m_ov.hEvent); ComAccess::ErrorToString("ReadData(): SetCommMask() failed"); return(-1); } // WaitForSingleObject bSuccess = WaitCommEvent(m_hCom, &mask, &m_ov); if ( ! bSuccess ) { int err = GetLastError(); if ( err == ERROR_IO_PENDING) { result = WaitForSingleObject(m_ov.hEvent, dwMaxWait); //wait dwMaxWait // milli seconds before returning if ( result == WAIT_FAILED ) { // Handle the error. CloseHandle(m_ov.hEvent); ComAccess::ErrorToString("ReadData(): WaitForSingleObject() failed"); return(-1); } } } // The specified event occured? if ( mask & EV_RXCHAR) { bSuccess = ReadFile(m_hCom, // handle of file to read pdest, // address of buffer that receives data len, // number of bytes to read &read, // address of number of bytes read &m_ov); // address of structure for data if ( ComAccess::IsNT() ) { bSuccess = GetOverlappedResult(m_hCom, &m_ov, &read, TRUE); if ( ! bSuccess ) { // Handle the error. CloseHandle(m_ov.hEvent); ComAccess::ErrorToString("WriteData(): GetOverlappedResult() failed"); return(-1); } } else if ( ! bSuccess ) { // Handle the error. CloseHandle(m_ov.hEvent); ComAccess::ErrorToString("ReadData(): ReadFile() failed"); return(-1); } } else { // Handle the error. CloseHandle(m_ov.hEvent); wsprintf(m_lpszErrorMessage, "Error ReadData(): No EV_RXCHAR occured\n"); return(-1);