Winsock学习笔记5：I/O Overlapped （重叠）模式

unit Unit1;interfaceuses WinSock2, Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls;type TWorkThread = class(TThread) private FMemo: TMemo; FBuff: array [0..10] of Char; FClientSocket: TSocket; procedure ShowRecv; protected procedure Execute;override; public constructor Create(Memo: TMemo; ClientSocket: TSocket); end; TForm1 = class(TForm) Memo1: TMemo; Button1: TButton; Timer1: TTimer; procedure Timer1Timer(Sender: TObject); procedure FormCreate(Sender: TObject); private { Private declarations } public { Public declarations } end;var Form1: TForm1; ServerSocket: TSocket;implementation{$R *.dfm}{ TWorkThread }constructor TWorkThread.Create(Memo: TMemo; ClientSocket: TSocket);begin inherited Create(False); FMemo:= Memo; FClientSocket:= ClientSocket;end;procedure TWorkThread.Execute;var WSBuff: WSABuf; EventTotal: Integer; AcceptOverLapped: WSAOverLapped; WSAEventArray: array [0..WSA_MAXIMUM_WAIT_EVENTS - 1] of WSAEvent; Idx: Integer; ReceiveBytes: DWORD; Flags: DWORD; ByteTransferred: DWORD;begin inherited; FreeOnTerminate:= True; EventTotal:= 0; //创建事件 WSAEventArray[EventTotal]:= WSACreateEvent; //置零 ZeroMemory(@AcceptOverLapped, SizeOf(WSAOverLapped)); //关联事件 AcceptOverLapped.hEvent:= WSAEventArray[EventTotal]; WSBuff.len:= 22; //缓冲区的长度要大于客户端发送的长度，如果小于客户端发送长度，会出现乱码 WSBuff.buf:= FBuff; Inc(EventTotal); while not Terminated do begin //收消息 WSARecv(FClientSocket, @WSBuff, EventTotal, ReceiveBytes, Flags, @AcceptOverlapped, nil); //用WSAWaitForMultipleEvents检测是否有“事件”发生 Idx:= WSAWaitForMultipleEvents(EventTotal, @WSAEventArray[0], False, WSA_INFINITE, False); //用WSAGetOverlappedResult取得结果 WSAGetOverlappedResult(FClientSocket, @AcceptOverlapped, @ByteTransferred, False, Flags); //显示收到的内容 Synchronize(ShowRecv); //清零AcceptOverLapped ZeroMemory(@AcceptOverLapped, SizeOf(WSAOverLapped)); //关联事件 AcceptOverLapped.hEvent:= WSAEventArray[Idx - WSA_WAIT_EVENT_0]; //重置Event WSAResetEvent(WSAEventArray[Idx - WSA_WAIT_EVENT_0]); end;end;procedure TWorkThread.ShowRecv;begin FMemo.Lines.Add(FBuff);end;procedure TForm1.FormCreate(Sender: TObject);var WSData: TWSAData; LocalAddr: TSockaddr; SocketMode: Cardinal;begin //初始化Winsock WSAStartUp($202, WSData); //创建套接字 ServerSocket:= Socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); //设置LocalAddr的参数 LocalAddr.sin_family:= AF_INET; //IPV4族 LocalAddr.sin_addr.S_addr:= INADDR_ANY;//这里不能写Inet_addr('127.0.0.1')，负责会绑定失败，不清楚原因是什么; LocalAddr.sin_port:= Htons(1077); //Host To Net Short，主机字节顺序转为网络字节顺序 //绑定本机IP地址、端口，绑定之前先设置好LocalAddr的参数 Bind(ServerSocket, @LocalAddr, SizeOf(LocalAddr)); SocketMode:= 1; IoCtlSocket(ServerSocket, FIONBIO, SocketMode); //开始监听 Listen(ServerSocket, 5);end;procedure TForm1.Timer1Timer(Sender: TObject);var ClientAddr: TSockAddr; ClientAddrLen: Integer; ClientSocket: TSocket;begin //接受客户端连接，为对应的客户端创建独立的线程 ClientAddrLen:= SizeOf(ClientAddr); ClientSocket:= Accept(ServerSocket, ClientAddr, ClientAddrLen); if ClientSocket <> INVALID_SOCKET then TWorkThread.Create(Memo1, ClientSocket);end;end.

 

1.此代码只是为了学习函数的使用方法，为了使代码简单，此处使用Timer管理客户端连接，并为每个连接创建独立的线程，Overlapped的处理方式可在线程的执行部分查看，实际应用中不应该用这种模式；

2.此代码为消息型的重叠(I/O Overlapped)模式，还有一种“完成例程”模式（非完成端口）；