windows重叠I/O模型

重叠I/O就相当于异步I/O。

一、重叠I/O的I/O完成确认

1、使用事件对象

接收端：

#include <stdio.h>
#include <stdlib.h>
#include <WinSock2.h>

#define BUF_SIZE 1024
void ErrorHandling(char *message);

int main(int argc, char *argv[])
{
    if (argc != 2) {
        printf("Usage : %s <port>
", argv[0]);
        exit(1);
    }

    WSADATA wsaData;
    SOCKET hLinSock, hCRecvSock;
    SOCKADDR_IN lisnAdr, recvAdr;
    int recvAdrSz;
    
    WSABUF dataBuf;
    WSAEVENT evObj;
    WSAOVERLAPPED overlapped;

    char buf[BUF_SIZE];
    int recvBytes = 0, flags = 0;

    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
        ErrorHandling("WSAStartup() error.");

    hLinSock = socket(PF_INET, SOCK_STREAM, 0);
    memset(&lisnAdr, 0, sizeof(lisnAdr));
    lisnAdr.sin_family = AF_INET;
    lisnAdr.sin_addr.s_addr = htonl(INADDR_ANY);
    lisnAdr.sin_port = htons(atoi(argv[1]));

    if (bind(hLinSock, (SOCKADDR*)&lisnAdr, sizeof(lisnAdr)) == SOCKET_ERROR)
        ErrorHandling("bind() error.");
    if (listen(hLinSock, 5) == SOCKET_ERROR)
        ErrorHandling("listen() error.");

    recvAdrSz = sizeof(recvAdr);
    hCRecvSock = accept(hLinSock, (SOCKADDR*)&recvAdr, &recvAdrSz);

    evObj = WSACreateEvent();
    memset(&overlapped, 0, sizeof(overlapped));
    overlapped.hEvent = evObj;
    dataBuf.len = BUF_SIZE;
    dataBuf.buf = buf;
    
    if (WSARecv(hCRecvSock, &dataBuf, 1, (LPDWORD)&recvBytes, (LPDWORD)&flags, &overlapped, NULL) == SOCKET_ERROR)
    {
        if (WSAGetLastError() == WSA_IO_PENDING)
        {
            puts("Background data receive");
            WSAWaitForMultipleEvents(1, &evObj, TRUE, WSA_INFINITE, FALSE);
            WSAGetOverlappedResult(hCRecvSock, &overlapped, (LPDWORD)&recvBytes, FALSE, NULL);
        }
        else{
            ErrorHandling("WSARECV() error");
        }
    }

    printf("Received message: %s
", buf);
    WSACloseEvent(evObj);
    closesocket(hCRecvSock);
    closesocket(hLinSock);
    WSACleanup();
    return 0;
}

void ErrorHandling(char *message) {
    fputs(message, stderr);
    fputc('
', stderr);
}

void CompressSockets(SOCKET hSockArr[], int idx, int total){
    for (int i = idx; i < total; i++)
        hSockArr[i] = hSockArr[i + 1];
}

void CompressEvents(WSAEVENT hEventArr[], int idx, int total){
    for (int i = idx; i < total; i++)
        hEventArr[i] = hEventArr[i + 1];
}

发送端：

#pragma warning(disable:4996)
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <winsock2.h>

void ErrorHandling(char *message);

int main(int argc, char* argv[]) {
    if (argc != 3) {
        printf("Usage : %s <IP> <port>
", argv[0]);
        exit(1);
    }

    WSADATA wsaData;
    SOCKET hSocket;
    SOCKADDR_IN sendAdr;

    WSABUF dataBuf;
    char msg[] = "Network is Computer!";
    int sendBytes = 0;

    WSAEVENT evObj;
    WSAOVERLAPPED overlapped;

    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
        ErrorHandling("WSAStartup() error");

    hSocket = WSASocket(PF_INET, SOCK_STREAM, 0, NULL, 0, WSA_FLAG_OVERLAPPED);
    memset(&sendAdr, 0, sizeof(sendAdr));
    sendAdr.sin_family = AF_INET;
    sendAdr.sin_addr.s_addr = inet_addr(argv[1]);
    sendAdr.sin_port = htons(atoi(argv[2]));

    if (connect(hSocket, (SOCKADDR*)&sendAdr, sizeof(sendAdr)) == SOCKET_ERROR)
        ErrorHandling("connect() error");
    else
        printf("Connected.......
");

    evObj = WSACreateEvent();
    memset(&overlapped, 0, sizeof(overlapped));
    overlapped.hEvent = evObj;
    dataBuf.len = strlen(msg) + 1;
    dataBuf.buf = msg;

    if (WSASend(hSocket, &dataBuf, 1, (LPDWORD)&sendBytes, 0, &overlapped, NULL) == SOCKET_ERROR){
        if (WSAGetLastError() == WSA_IO_PENDING){
            puts("Background data send");
            WSAWaitForMultipleEvents(1, &evObj, TRUE, WSA_INFINITE, FALSE);
            WSAGetOverlappedResult(hSocket, &overlapped, (LPDWORD)&sendBytes, FALSE, NULL);
        }
        else{
            ErrorHandling("WSASend() error");
        }
    }
    printf("Send data size:%d
", sendBytes);
    WSACloseEvent(evObj);
    closesocket(hSocket);
    WSACleanup();
    return 0;
}

void ErrorHandling(char *message) {
    fputs(message, stderr);
    fputc('
', stderr);
}

2、基于Completion Routine

接收端：

#include <stdio.h>
#include <stdlib.h>
#include <WinSock2.h>

#define BUF_SIZE 1024
void ErrorHandling(char *message);
void CALLBACK CompRoutine(DWORD, DWORD, LPWSAOVERLAPPED, DWORD);

WSABUF dataBuf;
char buf[BUF_SIZE];
int recvBytes = 0;

int main(int argc, char *argv[])
{
    if (argc != 2) {
        printf("Usage : %s <port>
", argv[0]);
        exit(1);
    }

    WSADATA wsaData;
    SOCKET hLinSock, hRecvSock;
    SOCKADDR_IN lisnAdr, recvAdr;
    
    WSAEVENT evObj;
    WSAOVERLAPPED overlapped;

    int idx, recvAdrSz, flags = 0;

    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
        ErrorHandling("WSAStartup() error.");

    hLinSock = socket(PF_INET, SOCK_STREAM, 0);
    memset(&lisnAdr, 0, sizeof(lisnAdr));
    lisnAdr.sin_family = AF_INET;
    lisnAdr.sin_addr.s_addr = htonl(INADDR_ANY);
    lisnAdr.sin_port = htons(atoi(argv[1]));

    if (bind(hLinSock, (SOCKADDR*)&lisnAdr, sizeof(lisnAdr)) == SOCKET_ERROR)
        ErrorHandling("bind() error.");
    if (listen(hLinSock, 5) == SOCKET_ERROR)
        ErrorHandling("listen() error.");

    recvAdrSz = sizeof(recvAdr);
    hRecvSock = accept(hLinSock, (SOCKADDR*)&recvAdr, &recvAdrSz);
    if (hRecvSock == INVALID_SOCKET)
        ErrorHandling("accept() error");

    
    memset(&overlapped, 0, sizeof(overlapped));

    dataBuf.len = BUF_SIZE;
    dataBuf.buf = buf;

    evObj = WSACreateEvent();
    
    if (WSARecv(hRecvSock, &dataBuf, 1, (LPDWORD)&recvBytes, (LPDWORD)&flags, &overlapped, CompRoutine) == SOCKET_ERROR)
    {
        if (WSAGetLastError() == WSA_IO_PENDING)
        {
            puts("Background data receive");
        }
        else{
            ErrorHandling("WSARECV() error");
        }
    }

    idx = WSAWaitForMultipleEvents(1, &evObj, FALSE, WSA_INFINITE, TRUE);
    if (idx == WAIT_IO_COMPLETION)
        puts("Overlapped I/O Completed");
    else
        ErrorHandling("WSARecv() error");
    WSACloseEvent(evObj);
    closesocket(hRecvSock);
    closesocket(hLinSock);
    WSACleanup();
    return 0;
}

void CALLBACK CompRoutine(DWORD dwError, DWORD szRecvBytes, LPWSAOVERLAPPED lpOverlapped, DWORD flags){

    if (dwError != 0){
        ErrorHandling("CompRoutine error");
    }
    else{
        recvBytes = szRecvBytes;
        printf("Received message: %s
", buf);
    }
}

void ErrorHandling(char *message) {
    fputs(message, stderr);
    fputc('
', stderr);
}

发送端：同上