Visual C 串口操作

    Window 95串口通讯函数集合(只适用于32位)

    需要说明的是：这是我程序的一部分，因此有一些与具体应用无关的部分。
    但我觉得关键是原理，而不是程序本身.后面有些使用介绍，帮助理解这长的程序。

    头文件(.H)

    #include "StdAfx.h"

    #define GWL_PGPSINFO 0
    #define GPSEXTRABYTES sizeof( LONG )

    #define MAXPORTS 4

    #define CN_SEND WM_USER+100

    #define RXQUEUE 4096
    #define TXQUEUE 4096

    // cursor states

    #define CS_HIDE 0x00
    #define CS_SHOW 0x01

    // Flow control flags

    #define FC_DTRDSR 0x01
    #define FC_RTSCTS 0x02
    #define FC_XONXOFF 0x04

    // ascii definitions

    #define ASCII_BEL 0x07
    #define ASCII_BS 0x08
    #define ASCII_LF 0x0A
    #define ASCII_CR 0x0D
    #define ASCII_XON 0x11
    #define ASCII_XOFF 0x13

    // data structures

    typedef struct tagGPSINFO
    {
    HANDLE idComDev;
    BYTE bPort;
    BOOL fConnected;
    BYTE bByteSize,bParity,bStopBits;
    DWORD dwBaudRate;

    HANDLE hPostEvent,hWatchThread,hWatchEvent;
    HWND hTermWnd;
    DWORD dwThreadID;
    OVERLAPPED osWrite,osRead;
    } GPSINFO, *PGPSINFO ;

    #define COMDEV( x ) (x -> idComDev)
    #define PORT( x ) (x -> bPort)
    #define CONNECTED( x ) (x -> fConnected)
    #define BYTESIZE( x ) (x -> bByteSize)
    #define PARITY( x ) (x -> bParity)
    #define STOPBITS( x ) (x -> bStopBits)
    #define BAUDRATE( x ) (x -> dwBaudRate)

    #define POSTEVENT( x ) (x -> hPostEvent)
    #define HTHREAD( x ) (x -> hWatchThread)
    #define THREADID( x ) (x -> dwThreadID)
    #define WRITE_OS( x ) (x -> osWrite)
    #define READ_OS( x ) (x -> osRead)

    // function prototypes (private)

    LRESULT NEAR CreateGPSInfo(HWND,BYTE nPort=1);
    BOOL NEAR DestroyGPSInfo();

    int NEAR ReadCommBlock(LPSTR,int);
    BOOL NEAR WriteCommBlock(LPSTR,DWORD);
    BOOL NEAR OpenConnection();
    BOOL NEAR SetupConnection();
    BOOL NEAR CloseConnection();

    // function prototypes (public)

    DWORD FAR PASCAL CommWatchProc(LPSTR);

    具体实现请看下文(为了这文章，我都段线2次了)

    CPP实现部分：

    #include "StdAfx.h"
    #include "Com.h"

    HWND hGPSWnd=NULL;
    PGPSINFO npGPSInfo=NULL;

    LRESULT NEAR CreateGPSInfo(HWND hWnd,BYTE nPort)
    {
    if (NULL==(npGPSInfo=(PGPSINFO)LocalAlloc(LPTR,sizeof(GPSINFO))))
    return ((LRESULT)-1) ;

    hGPSWnd=hWnd;

    COMDEV(npGPSInfo)=0;
    CONNECTED(npGPSInfo)=FALSE;
    PORT(npGPSInfo)=nPort;
    BAUDRATE(npGPSInfo)=CBR_9600;
    BYTESIZE(npGPSInfo)=8;
    PARITY(npGPSInfo)=NOPARITY;
    STOPBITS(npGPSInfo)=ONESTOPBIT;

    WRITE_OS(npGPSInfo).Offset=0;
    WRITE_OS(npGPSInfo).OffsetHigh=0;
    READ_OS(npGPSInfo).Offset=0;
    READ_OS(npGPSInfo).OffsetHigh=0;

    // create I/O event used for overlapped reads / writes

    READ_OS(npGPSInfo).hEvent=CreateEvent(NULL,TRUE,FALSE,NULL);
    if (READ_OS(npGPSInfo).hEvent==NULL)
    { LocalFree( npGPSInfo ) ;
    return ( -1 ) ;
    }
    WRITE_OS(npGPSInfo).hEvent=CreateEvent(NULL,TRUE,FALSE,NULL);
    if (NULL==WRITE_OS(npGPSInfo).hEvent)
    { CloseHandle(READ_OS(npGPSInfo).hEvent);
    LocalFree(npGPSInfo) ;
    return (-1) ;
    }

    return ( (LRESULT) TRUE ) ;
    }

    BOOL NEAR DestroyGPSInfo()
    {
    if (!npGPSInfo) return (FALSE);

    if (CONNECTED(npGPSInfo)) CloseConnection();

    CloseHandle(READ_OS(npGPSInfo).hEvent);
    CloseHandle(WRITE_OS(npGPSInfo).hEvent);
    CloseHandle(POSTEVENT(npGPSInfo));

    LocalFree(npGPSInfo);
    return (TRUE);
    }

    BOOL NEAR OpenConnection()
    {
    {
    char szPort[15];
    BOOL fRetVal;
    HCURSOR hOldCursor,hWaitCursor;

    HANDLE hCommWatchThread;
    DWORD dwThreadID;
    COMMTIMEOUTS CommTimeOuts;

    if (!npGPSInfo) return (FALSE);

    hWaitCursor=LoadCursor(NULL,IDC_WAIT) ;
    hOldCursor=SetCursor(hWaitCursor) ;

    wsprintf(szPort,"COM%d",PORT(npGPSInfo));

    if ((COMDEV(npGPSInfo)=CreateFile(szPort,GENERIC_READ|GENERIC_WRITE,
    0,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL|FILE_FLAG_OVERLAPPEED,
    NULL))==(HANDLE)-1)
    return ( FALSE ) ;
    else
    { SetCommMask(COMDEV(npGPSInfo),EV_RXCHAR);
    SetupComm(COMDEV(npGPSInfo),4096,4096);
    PurgeComm(COMDEV(npGPSInfo),PURGE_TXABORT|PURGE_RXABORT|PURGE_TXXCLEAR|PURGE_RXCLEAR);
    CommTimeOuts.ReadIntervalTimeout=0xFFFFFFFF;
    CommTimeOuts.ReadTotalTimeoutMultiplier=0;
    CommTimeOuts.ReadTotalTimeoutConstant=1000;
    CommTimeOuts.WriteTotalTimeoutMultiplier=0;
    CommTimeOuts.WriteTotalTimeoutConstant=1000;
    SetCommTimeouts(COMDEV(npGPSInfo),&CommTimeOuts);
    }

    fRetVal=SetupConnection();

    if (fRetVal)
    { CONNECTED(npGPSInfo)=TRUE;
    if (NULL==(hCommWatchThread=CreateThread((LPSECURITY_ATTRIBUTES))NULL,
    0,(LPTHREAD_START_ROUTINE)CommWatchProc,
    (LPVOID)NULL,0,&dwThreadID)))
    { CONNECTED(npGPSInfo)=FALSE;
    CloseHandle(COMDEV(npGPSInfo));
    fRetVal=FALSE;
    }
    else
    { THREADID(npGPSInfo)=dwThreadID;
    HTHREAD(npGPSInfo)=hCommWatchThread;
    EscapeCommFunction(COMDEV(npGPSInfo),SETDTR);
    }
    }
    else
    { CONNECTED(npGPSInfo)=FALSE;
    CloseHandle(COMDEV(npGPSInfo));
    }