Winsock.简单TCP

PS：vs2017 编译C++代码 支持 XP：项目属性-->链接器-->系统-->需要的最小版本--> 输入 "5.1"

1、ZC：测试：c向s 发送长度为0的数据，是可行的。（1）用s和c都在本机 测试，OK （2）用 冬的HP笔记本 和 我的联想小新笔记本 测试，OK

　　ZC：要想 像UDP那样 像自己发送信息 来退出循环的话... 不太好办...　除非要 使用 非阻塞/异步模型(如 select模型、WSAAsyncSelect模型、WSAEventSelect模型、重叠IO模型)，但是 有比较麻烦，还不如直接 使用 Qt的QTcpSocket(Qt的QUdpSocket会丢包，QTcpSocket用了之后 感觉还好)

2、测试代码：

// SampleTCP_01.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#include <iostream>
#include <stdio.h>

int main1();
int main2();

int main(int _argc, char** _argv)
{
    std::cout << "Hello World!\n";

    if (_argc <= )
    {
        printf("Command line no parameter .");
        return ;
    }

    printf("%s\n", _argv[]);
    if (_argv[][] == 's')
        main1();
    else if (_argv[][] == 'c')
        main2();
    else
        printf("Unknown command line parameter : %s\n", _argv[]);

    return ;
}

#define _WINSOCK_DEPRECATED_NO_WARNINGS

#include <iostream>
#include <string>

#include <winsock2.h>
#pragma comment(lib, "ws2_32.lib")

#define PORT 58888
#define BUFFER_SIZE 256

static const std::string kExitFlag = "-1";

// 参考：http://c.biancheng.net/cpp/html/3030.html

int main1()
{
    WORD winsock_version = MAKEWORD(, );
    WSADATA wsa_data;
    if (WSAStartup(winsock_version, &wsa_data) != ) {
        std::cout << "Failed to init socket dll!" << std::endl;
        return ;
    }

    SOCKET server_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (server_socket == INVALID_SOCKET) {
        std::cout << "Failed to create server socket!" << std::endl;
        return ;
    }

    sockaddr_in server_addr;
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(PORT);
    server_addr.sin_addr.S_un.S_addr = INADDR_ANY;

    if (bind(server_socket, (LPSOCKADDR)&server_addr, sizeof(server_addr)) == SOCKET_ERROR) {
        std::cout << "Failed to bind port!" << std::endl;
        return ;
    }

    if (listen(server_socket, )) {
        std::cout << "Failed to listen!" << std::endl;
        return ;
    }

    // 循环接收数据。
    sockaddr_in client_addr;
    int client_addr_len = sizeof(client_addr);
    std::cout << "Wait for connecting..." << std::endl;

    // 程序一旦执行到 accept() 就会被阻塞（暂停运行），直到客户端发起请求。
    SOCKET client_socket = accept(server_socket, (SOCKADDR*)&client_addr, &client_addr_len);
    if (client_socket == INVALID_SOCKET) {
        std::cout << "Failed to accept!" << std::endl;
        return ;
    }

    std::cout << "Succeed to receive a connection: " << inet_ntoa(client_addr.sin_addr) << std::endl;

    char recv_buf[BUFFER_SIZE] = {};
    while (true)
    {
        // 接收数据。
        // 返回值是读取的字节数。没有内容时，等待请求。
        int ret = recv(client_socket, recv_buf, BUFFER_SIZE, );
        if (ret < ) {
            std::cout << "Failed to receive data!" << std::endl;
            break;
        }

        printf("ret : %d\n", ret);
        if (ret == )
        {
            printf("break\n");
            break;
        }

        std::cout << "Receive from Client: " << recv_buf << std::endl;
        if (kExitFlag == recv_buf) {
            std::cout << "Exit!" << std::endl;
            break;
        }

        // 发送数据给客户端。
        char* send_data = (char*)"Hello, Tcp Client!\n";
        send(client_socket, send_data, strlen(send_data), );
    }

    // 关闭套接字。
    closesocket(client_socket);
    closesocket(server_socket);

    // 释放dll。
    WSACleanup();

    return ;
}

#define _WINSOCK_DEPRECATED_NO_WARNINGS

#include <iostream>
#include <string>

#include <winsock2.h>
#pragma comment(lib, "ws2_32.lib")

#define PORT 58888
//#define SERVER_IP "127.0.0.1"
#define SERVER_IP "192.168.2.102"
#define BUFFER_SIZE 256

//static const std::string kExitFlag = "-1";

int main2()
{
    // 初始化socket dll。
    WORD winsock_version = MAKEWORD(, );
    WSADATA wsa_data;
    if (WSAStartup(winsock_version, &wsa_data) != ) {
        std::cout << "Failed to init socket dll!" << std::endl;
        return ;
    }

    SOCKET client_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (client_socket == INVALID_SOCKET) {
        std::cout << "Failed to create server socket!" << std::endl;
        return ;
    }

    // 绑定IP和端口。
    sockaddr_in server_addr;
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(PORT);
    server_addr.sin_addr.S_un.S_addr = inet_addr(SERVER_IP);
    // connect() 向服务器发起请求，服务器的IP地址和端口号保存在 sockaddr_in 结构体中。直到服务器传回数据后，connect() 才运行结束。
    if (connect(client_socket, (LPSOCKADDR)&server_addr, sizeof(server_addr)) == SOCKET_ERROR) {
        std::cout << "Failed to connect server!" << std::endl;
        return ;
    }

    char recv_data[BUFFER_SIZE] = {};

    while (true) {
        std::string data;
        std::cout << "Input data: ";
        std::cin >> data;

        //if (send(client_socket, data.c_str(), data.size(), 0) < 0) {
        if (send(client_socket, &recv_data[], , ) < ) {
            std::cout << "Failed to send data!" << std::endl;
            break;
        }

        break;

        int ret = recv(client_socket, recv_data, BUFFER_SIZE, );
        if (ret < ) {
            std::cout << "Failed to receive data!" << std::endl;
            break;
        }

        std::cout << "Receive data from server: " << recv_data << std::endl;

        if (recv_data == kExitFlag) {
            std::cout << "Exit!" << std::endl;
            break;
        }
    }

    closesocket(client_socket);
    WSACleanup();

    return ;
}

3、vs2017 编译C++代码 支持 XP

　　

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