C++网络编程实例（初识多线程）

TIPS：以下程序使用同一台主机演示。

服务端开启多线程，等待多个客户端连接。

#define _WINSOCK_DEPRECATED_NO_WARNINGS
#include 

#include //C++11线程库

//Windows网络库
#include 
//引入socket动态库，win下可以，但不能跨平台
#pragma comment (lib,"ws2_32.lib")

using std::cout;
using std::endl;
using std::cin;

int main()
{
	system("chcp 65001");//防止乱码
	WSADATA wsaData;
	//在window下面需要额外的加载socket库
	if (SOCKET_ERROR == WSAStartup(MAKEWORD(2, 2), &wsaData))
	{
		cout << "WSAStartup 启动失败 " << GetLastError() << endl;
		return 0;
	}


	SOCKET serverSock = socket(AF_INET, SOCK_STREAM, 0);
	if (INVALID_SOCKET == serverSock)
	{
		cout << "创建socket失败 " << GetLastError() << endl;
		return 0;
	}


	SOCKADDR_IN ServerAddr;
	ServerAddr.sin_family = AF_INET;
	ServerAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
	ServerAddr.sin_port = htons(7890);
	if (SOCKET_ERROR == bind(serverSock, (sockaddr *)&ServerAddr, sizeof(SOCKADDR_IN)))
	{
		cout << "bind 失败 " << GetLastError() << endl;
		return 0;
	}


	if (INVALID_SOCKET == listen(serverSock, 5))
	{
		cout << "监听失败 " << GetLastError() << endl;
		return 0;
	}

	while (true)
	{
		cout << "等待用户连接 " << endl;
		SOCKADDR_IN clientAddr;
		int clientAddrLen = sizeof(SOCKADDR_IN);
		SOCKET clientSock = accept(serverSock, (sockaddr *)&clientAddr, &clientAddrLen);

		cout << "连接成功: SOCKET: " << clientSock << " ip:" << inet_ntoa(clientAddr.sin_addr) << " port:" << ntohs(clientAddr.sin_port) << endl;
		//多线程 面向多个客户端
		//TIPS：如果将accept模块部分载入多线程，意味着将开启无限多个线程等待客户端的进入，那是没有意义的。
		std::thread t([clientSock]()
		{
			//向连接的客户端收发数据
			while (true)
			{
				//收发数据
				char buffer[1024]{ 0 };
				int nRecv = recv(clientSock, buffer, 1024, 0);
				int nSend = send(clientSock, buffer, nRecv, 0);
				if (nRecv <= 0)
					break;
				cout << "收到的数据长度: " << nRecv << " 收到的数据为：" << buffer << endl;
			}
			closesocket(clientSock);
			cout << "关闭客户端" << endl;
		});
		t.detach();
	}
	closesocket(serverSock);
	//卸载Windows动态网络库
	WSACleanup();
	system("pause");
	return 0;
}

客户端可随机向服务端发送数据，服务端返回其收到的数据给该客户端。

#define _WINSOCK_DEPRECATED_NO_WARNINGS
#include 

#include 
#pragma comment(lib,"ws2_32.lib") //引入socket动态库，win下可以，但不能跨平台

using std::cout;
using std::endl;
using std::cin;


int main()
{
	system("chcp 65001");//防止中文乱码
	WSADATA wsaData;
	int nRet = WSAStartup(MAKEWORD(2, 2), &wsaData);
	if (SOCKET_ERROR == nRet)
	{
		cout << "WASStartUp 启动失败" << GetLastError() << endl;
		return 0;
	}


	SOCKET clientSock = socket(AF_INET, SOCK_STREAM, 0);
	if (INVALID_SOCKET == clientSock)
	{
		cout << "创建socket失败 " << GetLastError() << endl;
		return 0;
	}

	SOCKADDR_IN serverAddr;
	serverAddr.sin_family = AF_INET;
	serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
	serverAddr.sin_port = htons(7890);

	//connect内部自动给客户端绑定了一个随机端口
	if (INVALID_SOCKET == connect(clientSock, (sockaddr *)&serverAddr, sizeof(SOCKADDR_IN)))
	{
		cout << "连接服务端失败 " << GetLastError() << endl;
		return 0;
	}

	while (true)
	{
		char buffer[1024]{ 0 };
		cout << "请输入: ";
		cin >> buffer;
		if (buffer[0] == 'q')break;
		int nSendLen = send(clientSock, buffer, strlen(buffer), 0);

		int nRecvLen = recv(clientSock, buffer, 1024, 0);
		if (nRecvLen <= 0)
			break;
		cout << "收到的长度 " << nRecvLen << " 数据:" << buffer << endl;

	}
	closesocket(clientSock);
	WSACleanup();//卸载动态网络库
	system("pause");
	return 0;
}