IOCP模型TCP服务器

主线程创建监听套接字，创建额外工作线程，关联IOCP，负责等待和接受到来的连接。

调用GetQueuedCompletionStatus函数，函数返回：

1 调用失败

2 套接字被对方关闭

3 请求成功完成

程序首先定义per-handle per-IO的操作数据的结构类型

#define BUFFER_SIZE 1024
typedef struct _PER_HANDLE_DATA{
    SOCKET s;
    sockaddr_in addr;
}PER_HANDLE_DATA,*PPER_HANDLE_DATA;
typedef struct _PER_IO_DATA{
    OVERLAPPED ol;
    char buf[BUFFER_SIZE];
    int nOperationType;
#define OP_READ 1
#define OP_WRITE 2
#define OP_ACCEPT 3
}PER_IO_DATA,*PPER_IO_DATA;

---

主要过程：

1 主线程创建完成端口对象，创建工作线程处理完成端口对象中的事件

2 创建监听套接字，开始监听服务器端口

3 进入无限循环，处理到来的请求

　　1）调用accept函数等待接受未决的连接请求 　　2)创建一个per-handle数据 　　3）投递一个接收请求

实现代码：

void  main()
{
    int nPort = 4567;
    HANDLE hCompletion = ::CreateIoCompletionPort(INVALID_HANDLE_VALUE,0,0,0);
    ::CreateThread(NULL,0,ServerThread,(LPVOID)hCompletion,0,0);

    SOCKET sListen = ::socket(AF_INET,SOCK_STREAM,0);
    SOCKADDR_IN si;
    si.sin_family = AF_INET;
    si.sin_port = htons(nPort);
    si.sin_addr.S_un.S_addr = INADDR_ANY;
    ::bind(sListen,(sockaddr*)&si,sizeof(si));
    ::listen(sListen,5);
    while(TRUE){
        //等待接收未决的请求
        SOCKADDR_IN saRemote;
        int nRemoteLen = sizeof(saRemote);
        SOCKET sNew = ::accept(sListen,(sockaddr*)&saRemote,&nRemoteLen);
        //创建per-handle
        PPER_HANDLE_DATA pPerHandle = (PPER_HANDLE_DATA)::GlobalAlloc(GPTR,sizeof(PER_HANDLE_DATA));
        pPerHandle->s = sNew;
        memcpy(&pPerHandle->addr,&saRemote,nRemoteLen);
        ::CreateIoCompletionPort((HANDLE)pPerHandle->s,hCompletion,(DWORD)pPerHandle,0);
        //投递一个接收请求
        PPER_IO_DATA pPerIO = (PPER_IO_DATA)::GlobalAlloc(GPTR,sizeof(PER_IO_DATA));
        pPerIO->nOperationType = OP_READ;
        WSABUF buf;
        buf.buf = pPerIO->buf;
        buf.len = BUFFER_SIZE;
        DWORD dwRecv;
        DWORD dwFlags = 0;
        ::WSARecv(pPerHandle->s,&buf,1,&dwRecv,&dwFlags,&pPerIO->ol,NULL);//接收投递求
    }
}
DWORD WINAPI ServerThread(LPVOID lpParam{
    HANDLE hCompletion = (HANDLE)lpParam;
    DWORD dwTrans;
    PPER_HANDLE_DATA pPerHandle;
    PPER_IO_DATA pPerIO;
    while(TRUE){
        BOOL bOK = ::GetQueuedCompletionStatus(hCompletion,&dwTrans,(LPDWORD)&pPerHandle,(LPOVERLAPPED*)&pPerIO,WSA_INFINITE);
        if(!bOK)
        {
            ::closesocket(pPerHandle->s);
            ::GlobalFree(pPerHandle);
            ::GlobalFree(pPerIO);
            continue;
        }
        if(dwTrans == 0 && (pPerIO->nOperationType==OP_READ||pPerIO->nOperationType==OP_WRITE))
        {
            ::closesocket(pPerHandle->s);
            ::GlobalFree(pPerHandle);
            ::GlobalFree(pPerIO);
            continue;
        }
        switch(pPerIO->nOperationType)
        {
        case OP_READ:
            {
                pPerIO->buf[dwTrans] = '\0';
                printf(pPerIO->buf);
                WSABUF buf;
                buf.buf = pPerIO->buf;
                buf.len = BUFFER_SIZE;
                pPerIO->nOperationType = OP_READ;
                DWORD nFlags = 0;
                ::WSARecv(pPerHandle->s,&buf,1,&dwTrans,&nFlags,&pPerIO->ol,NULL);
            }
            break;
        case OP_WRITE:
        case OP_ACCEPT:
            break;
        }
    }
    return 0;
}