网络编程之select 模式开发实例

在网络上看到太多关于select i/o用法，都不是非常的详细。

经过摸索，把我实现的例子张贴上来，供大家参考。

描述：

服务器：实现并发tcp服务器，最多允许64 个客户端连接。

客户端：与服务器建立tcp连接，发送数据给服务器。服务器接收数据。

服务器代码：（红色为我的代码）

// SelectServerDlg.h : header file
//

#if !defined(AFX_SELECTSERVERDLG_H__3D5E9C67_8737_4E23_9734_0F196495ED30__INCLUDED_)
#define AFX_SELECTSERVERDLG_H__3D5E9C67_8737_4E23_9734_0F196495ED30__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

/////////////////////////////////////////////////////////////////////////////
// CSelectServerDlg dialog
UINT proc(LPVOID lParam);

class CSelectServerDlg : public CDialog
{
// Construction
public:
 CSelectServerDlg(CWnd* pParent = NULL); // standard constructor
 CWinThread *pThread;
 BOOL bRun;

// Dialog Data
 //{{AFX_DATA(CSelectServerDlg)
 enum { IDD = IDD_SELECTSERVER_DIALOG };
  // NOTE: the ClassWizard will add data members here
 //}}AFX_DATA

 // ClassWizard generated virtual function overrides
 //{{AFX_VIRTUAL(CSelectServerDlg)
 protected:
 virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support
 //}}AFX_VIRTUAL

// Implementation
protected:
 HICON m_hIcon;

 // Generated message map functions
 //{{AFX_MSG(CSelectServerDlg)
 virtual BOOL OnInitDialog();
 afx_msg void OnSysCommand(UINT nID, LPARAM lParam);
 afx_msg void OnPaint();
 afx_msg HCURSOR OnQueryDragIcon();
 afx_msg void OnClose();
 //}}AFX_MSG
 DECLARE_MESSAGE_MAP()
};

//{{AFX_INSERT_LOCATION}}
// Microsoft Visual C++ will insert additional declarations immediately before the previous line.

#endif // !defined(AFX_SELECTSERVERDLG_H__3D5E9C67_8737_4E23_9734_0F196495ED30__INCLUDED_)

————————————————————————————————————————

//SelectServerDlg.cpp代码

BOOL CSelectServerDlg::OnInitDialog()
{
 CDialog::OnInitDialog();
 
 // Add "About..." menu item to system menu.
 
 // IDM_ABOUTBOX must be in the system command range.
 ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
 ASSERT(IDM_ABOUTBOX < 0xF000);
 
 CMenu* pSysMenu = GetSystemMenu(FALSE);
 if (pSysMenu != NULL)
 {
  CString strAboutMenu;
  strAboutMenu.LoadString(IDS_ABOUTBOX);
  if (!strAboutMenu.IsEmpty())
  {
   pSysMenu->AppendMenu(MF_SEPARATOR);
   pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
  }
 }
 
 // Set the icon for this dialog.  The framework does this automatically
 //  when the application's main window is not a dialog
 SetIcon(m_hIcon, TRUE);   // Set big icon
 SetIcon(m_hIcon, FALSE);  // Set small icon
 
 // TODO: Add extra initialization here
 WSAData wsadata;
 WORD wVersionRequest;
 wVersionRequest=MAKEWORD(2,2);
 if(WSAStartup(wVersionRequest,&wsadata)!=0)
  TRACE("没有DLL可用\n");
 if(LOBYTE(wsadata.wVersion) != 2 || HIBYTE(wsadata.wVersion) != 2)
 {
  AfxMessageBox("socket dll 启动失败");
  WSACleanup();
 }
 pThread = AfxBeginThread(proc, this);
 return TRUE;  // return TRUE  unless you set the focus to a control
}

——————————————————————————————————————

//服务器线程

UINT proc(LPVOID lParam)
{
 try{
  fd_set rset;
  CSelectServerDlg *pDlg = (CSelectServerDlg*)lParam;
  struct sockaddr_in seraddr,cliaddr;
  int client[FD_SETSIZE],listensock;
  FD_ZERO(&rset);
  seraddr.sin_addr.s_addr = inet_addr("192.168.1.24");
  seraddr.sin_family = AF_INET;
  seraddr.sin_port = htons(6500);
  memset(seraddr.sin_zero, 0, 8);
  listensock = socket(AF_INET, SOCK_STREAM, 0);
  TRACE("listen socket :%d\n", listensock);
  bind(listensock, (struct sockaddr *)&seraddr, sizeof(seraddr));
  listen(listensock, 20);
  for(int i = 0; i<FD_SETSIZE; i++)
   client[i] = -1;
  pDlg->bRun = TRUE;
  int nReady;
  struct timeval timeout;
  int isset;
  int err;
  int maxfd;
  int connfd;
  int clilen;
  maxfd = listensock;
  char buf[1024];
  int recvbytes = 0;
  memset(buf, 0, 1024); 
  while(pDlg->bRun){
   Sleep(1);
   timeout.tv_sec = 0;
   timeout.tv_usec = 10;
   /*
   listen socket 加入fdset
   */
   FD_SET(listensock, &rset);
   for(int n = 0; n<FD_SETSIZE; n++)
   {
    if(client[n]>0){
     FD_SET(client[n], &rset);
     if(client[n] > maxfd)
      maxfd = client[n];
    }
    
   }

   nReady = select(maxfd+1, &rset, NULL, NULL, &timeout);
   if(nReady == 0)
    //TRACE("select fun time out\n");
    ;
   else if(nReady == -1)
   {
    TRACE("socket error\n");
    err = WSAGetLastError();
    switch(err)
    {
    case WSANOTINITIALISED:
     TRACE("WSANOTINITIALISED 未初始化\n");
     break;
    case WSAEFAULT:
     TRACE("WSAEFAULT\n");
     break;
    case WSAENETDOWN:
     TRACE("WSAENETDOWN\n");
     break;
    case WSAEINVAL:
     TRACE("WSAEINVAL\n");
     break;
    case WSAEINTR:
     TRACE("WSAEINTR\n");
     break;
    case WSAEINPROGRESS:
     TRACE("WSAEINPROGRESS\n");
     break;
    case WSAENOTSOCK:
     TRACE("WSAENOTSOCK\n");
     break;
    }
   }
   else
   {
    /*
    测试已经建立连接的socket
    */
    unsigned long ul = 1;
    for(int j = 0; j<FD_SETSIZE; j++)
    {
     if(client[j]>0)
     {
      memset(buf,0,1024);
      isset = FD_ISSET(client[j],&rset);
      if(isset)
      {
       //ioctlsocket(client[j], FIONBIO, &ul);
       recvbytes = recv(client[j], buf, 1024, NULL);
       if(recvbytes>0)
        TRACE("from socket: %d,接收字节数:%d,%s\n",client[j], recvbytes, buf);
       else if(recvbytes == 0)
       {
        closesocket(client[j]);
        TRACE("client socket :%d closed! \n",client[j]);
        client[j] = -1;
       }
      }
     }
    }
    /*
    测试是否有连接？
    */
    isset = FD_ISSET(listensock, &rset);
    FD_ZERO(&rset);
    if(isset)
    {
     TRACE("conncetion.... \n");
     clilen = sizeof(cliaddr);
     connfd = accept(listensock,(struct sockaddr *)&cliaddr, &clilen);
     TRACE("connection comes from ip:%d.%d.%d.%d\n",cliaddr.sin_addr.S_un.S_un_b.s_b1,
      cliaddr.sin_addr.S_un.S_un_b.s_b2,
      cliaddr.sin_addr.S_un.S_un_b.s_b3,
      cliaddr.sin_addr.S_un.S_un_b.s_b4);
     for(int s=0; s<FD_SETSIZE; s++){
      if(client[s]<0){
       client[s] = connfd;
       break;
      }
     }
     
     TRACE("con number：%d\n", s+1);
     TRACE("socket id:");
     for(int k = 0; k < FD_SETSIZE; k++)
     {
      if(client[k]>0)
       TRACE("%d,",client[k]);
     }
     TRACE("\n");
    }
    
   }
  }
 }

 catch (...) {
  TRACE("exception.........!!\n");
 }
 return TRUE;
}

——————————————————————————————————

//客户端代码：

BOOL CTcpClientDlg::OnInitDialog()
{
 CDialog::OnInitDialog();

 // Add "About..." menu item to system menu.

 // IDM_ABOUTBOX must be in the system command range.
 ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
 ASSERT(IDM_ABOUTBOX < 0xF000);

 CMenu* pSysMenu = GetSystemMenu(FALSE);
 if (pSysMenu != NULL)
 {
  CString strAboutMenu;
  strAboutMenu.LoadString(IDS_ABOUTBOX);
  if (!strAboutMenu.IsEmpty())
  {
   pSysMenu->AppendMenu(MF_SEPARATOR);
   pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
  }
 }

 // Set the icon for this dialog.  The framework does this automatically
 //  when the application's main window is not a dialog
 SetIcon(m_hIcon, TRUE);   // Set big icon
 SetIcon(m_hIcon, FALSE);  // Set small icon
 
 // TODO: Add extra initialization here

 WSAData wsadata;
 WORD wVersionRequest;
 wVersionRequest=MAKEWORD(2,2);
 if(WSAStartup(wVersionRequest,&wsadata)!=0)
  TRACE("没有DLL可用\n");
 if(LOBYTE(wsadata.wVersion)!=2||HIBYTE(wsadata.wVersion)!=2)
 {
  AfxMessageBox("socket dll 启动失败");
  WSACleanup();
 }
 serveraddr.sin_family=AF_INET;
 serveraddr.sin_port=htons(6500);
 serveraddr.sin_addr.S_un.S_un_b.s_b1=192;
 serveraddr.sin_addr.S_un.S_un_b.s_b2=168;
 serveraddr.sin_addr.S_un.S_un_b.s_b3=1;
 serveraddr.sin_addr.S_un.S_un_b.s_b4=24;
 clientsocket=socket(AF_INET,SOCK_STREAM,0);
 return TRUE;  // return TRUE  unless you set the focus to a control
}

void CTcpClientDlg::OnSend()
{
 // TODO: Add your control notification handler code here
 nResult=connect(clientsocket,(struct sockaddr *)&serveraddr,sizeof(serveraddr));
 if(nResult != SOCKET_ERROR)
 {
  TRACE("连接成功\n");
  char *szSend="123456789";
  nResult=sendto(clientsocket,szSend,9,0,(struct sockaddr*)&serveraddr,sizeof(serveraddr));
  if(nResult != SOCKET_ERROR)
  {
   TRACE("发送成功\n");
  }
 }
 
}

void CTcpClientDlg::OnButton2()
{
 // TODO: Add your control notification handler code here
 closesocket(clientsocket);
}

void CTcpClientDlg::OnButton3()
{
 // TODO: Add your control notification handler code here
 char *szSend="123456789";
 nResult=sendto(clientsocket,szSend,9,0,(struct sockaddr*)&serveraddr,sizeof(serveraddr));
 if(nResult != SOCKET_ERROR)
 {
  TRACE("发送成功\n");
 }
}

(完)