Winsock 单客户端服务器同时发送和接收

您需要让客户端和服务器在连接的生存期内在后台持续读取，然后它们可以在需要时并行发送数据。 将读取逻辑移动到单独的线程中，例如：

#include <WinSock2.h>
#include <Windows.h>
#include <iostream>
#include <string>
#include <stdio.h>
#include <ctime>
DWORD WINAPI ReadingThread(LPVOID param)
{
    SOCKET s = (SOCKET) param;
    char Buffer[512];
    int iResult;
    do
    {
        iResult = recv(s, Buffer, 512, 0);
        if (iResult <= 0) break;
        Buffer[iResult] = '';
        std::cout << "Recv: " << message << std::endl;
    }
    while (true);
    return 0;
}
int main()
{
    int userType;
    HANDLE hThread;
    DWORD dwThreadID;
    //initialize winsock and create a socket
    WSAData wsaData; // initialize
    iResult = WSAStartup(MAKEWORD(2,1), &wsaData);
    if (iResult != NO_ERROR) // check for errors
    {
        std::cout << "Error at WSAStartup()" << std::endl;
        return 0;
    }
    std::cout << "WSAStartup() is OK." << std::endl;
    // Ask the user if he is server or client
    std::cout << "Hi, which type of user are you? 1 - Server, 2 - Client" << std::endl;
    std::cin >> userType;
    // depending on the declared user type, execute the appropriate code
    if (userType == 1)
    {
        // create socket
        sockSocket = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP); // create a socket
        if (sockSocket == INVALID_SOCKET) // check for errors
        {
            std::cout << "Error at socket(): " << WSAGetLastError() << std::endl;
            WSACleanup();
            return 0;
        }
        std::cout << "Socket() is OK." << std::endl;
        // bind to socket
        service.sin_addr.s_addr = INADDR_ANY;
        service.sin_family = AF_INET;
        service.sin_port = htons(55555);
        if (bind(sockSocket, (SOCKADDR*)&service, sizeof(service)) == SOCKET_ERROR) // cheking for errors
        {
            std::cout << "Error at bind(): " << WSAGetLastError() << std::endl;
            closesocket(sockSocket);
            WSACleanup();
            return 0;
        }
        std::cout << "Bind() is OK." << std::endl;
        // listen
        if (listen(sockSocket, 10) == SOCKET_ERROR) // check for errors
        {
            std::cout << "Error at listen(): " << WSAGetLastError() << std::endl;
            closesocket(sockSocket);
            WSACleanup();
            return 0;
        }
        std::cout << "Listen() is OK." << std::endl;
        //accept connection
        servlen = sizeof(service);
        std::cout << "Waiting for user to connect..." << std::endl;
        acceptSocket = accept(sockSocket, (SOCKADDR*)&service, &servlen);
        if (acceptSocket != INVALID_SOCKET)
        {
            std::cout << "Error at accept(): " << WSAGetLastError() << std::endl;
            closesocket(sockSocket);
            WSACleanup();
            return 0;
        }
        std::cout << "A client has connected" << std::endl << std::endl;
        // receive messages
        hThread = CreateThread(NULL, 0, &ReadingThread, (void*)acceptSocket, 0, &dwThreadID);
        if (!hThread)
        {
            std::cout << "Error at CreateThread(): " << GetLastError() << std::endl;
            closesocket(acceptSocket);
            closesocket(sockSocket);
            WSACleanup();
            return 0;
        }
        // send messages
        do
        {
            std::string message;
            if (!std::getline(std::cin, message))
                break;
            if (send(acceptSocket, msg.c_str(), msg.length(), 0) == SOCKET_ERROR)
            {
                std::cout << "Error at send(): " << WSAGetLastError() << std::endl;
                break;
            }
        }
        while (true);
        closesocket(acceptSocket);
        WaitForSingleObject(hThread, INFINITE);
        CloseHandle(hThread);
        closesocket(sockSocket);
        WSACleanup();
    }
    else if (userType == 2)
    {
        // create socket
        sockSocket = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP); // create a socket
        if (sockSocket == INVALID_SOCKET) // check for errors
        {
            std::cout << "Error at socket(): " << WSAGetLastError() << std::endl;
            WSACleanup();
            return 0;
        }
        std::cout << "Socket() is OK." << std::endl;
        // ask  for the ip the user wants to connect to
        std::string IP;
        std::cout << "Hi what's the IP that you want to connect to?" << std::endl;
        std::cin >> IP;
        // connect to socket
        conService.sin_addr.s_addr = inet_addr(IP.c_str()); // connect to the ipnuted IP
        conService.sin_family = AF_INET;
        conService.sin_port = htons(55555); // should the port also be the argument?
        if (connect(sockSocket, (SOCKADDR*)&conService, sizeof(conService)) == SOCKET_ERROR) // check for errors
        {
            std::cout << "Failed to connect: " << WSAGetLastError() << std::endl;
            closesocket(sockSocket);
            WSACleanup();
            return 0;
        }
        std::cout << "Connected." << std::endl;
        // receive messages
        hThread = CreateThread(NULL, 0, &ReadingThread, (void*)sockSocket, 0, &dwThreadID);
        if (!hThread)
        {
            std::cout << "Error at CreateThread(): " << GetLastError() << std::endl;
            closesocket(sockSocket);
            WSACleanup();
            return 0;
        }
        // send messages
        do
        {
            std::string message;
            if (!std::getline(std::cin, message))
                break;
            if (send(sockSocket, msg.c_str(), msg.length(), 0) == SOCKET_ERROR)
            {
                std::cout << "Error at send(): " << WSAGetLastError() << std::endl;
                break;
            }
        }
        while (true);
        closesocket(sockSocket);
        WaitForSingleObject(hThread, INFINITE);
        CloseHandle(hThread);
        WSACleanup();
    }
    else
    {
        std::cout << "Invalid type entered!" << std::endl;
        WSACleanup();
        return 0;
    }
    return 0;
}