简单多线程服务器，支持windows和linux

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

#ifdef WIN32          //windows系统下的socket
#include <Windows.h>
#define socklen_t int
#else                 //linux系统下的socket
#include <sys/types.h>        
#include <sys/socket.h>
#include <unistd.h>
#include <arpa/inet.h>
#define closesocket close
#endif 

#include <thread>
using namespace std;

class TcpThread
{
public:
	void Main()
	{
		//接收用户数据,并回信息
		char buf[1024] = { 0 };
		for (;;)
		{

			int recv_len = recv(client, buf, sizeof(buf) - 1, 0);
			if (recv_len < 0)
			{
				break;
			}
			buf[recv_len] = '\0';
			if (NULL != (strstr(buf, "quit")))
			{
				send(client, "quit success\n", 13, 0);
				break;
			}
			int send_len = send(client, "ok\n", 3, 0);
			printf("recv [%s \n", buf);
			memset(buf, 0, sizeof(buf));

		}
		closesocket(client);   //linux系统下 宏定义为close()函数
		delete this; //自己清理自己
	}
	int client = 0;
};

int main(int argc, char* argv[])
{
	//创建监听socket
#ifdef WIN32      //windows下的socket初始化，linux下不需要
	WSADATA ws;
	WSAStartup(MAKEWORD(2, 2), &ws);
#endif
	int sock = socket(AF_INET, SOCK_STREAM, 0);  //返回 监听socket
	if (sock == -1)
	{
		printf("create socket failed\n");
		return -1;

	}
	printf("[%d]", sock);

	//绑定端口
	unsigned short port = 8080;
	if (argc > 1)
	{
		port = atoi(argv[1]);
	}
	sockaddr_in saddr; //socksddr_in和socketaddr结构体本质一样，一般用sockaddr_in，指向sockaddr_in结构的指针也可以指向sockaddr
	saddr.sin_family = AF_INET;  //确定地址族  使用ipv4
	saddr.sin_port = htons(port);//确定端口号，注意网络字节序转换，网络默认大端模式
	saddr.sin_addr.s_addr = htonl(0);//确定IP地址（0任意）
	if (bind(sock, (sockaddr*)&saddr, sizeof(saddr)) != 0)   //使用bind必须检测结果
	{
		printf("bind port failed\n");
		return -2;
	}
	printf("bind port %d success\n",port);

	//监听
	listen(sock, 10);//最大接收连接数为10
	
	for (;;)
	{
		//获取
		sockaddr_in ac_addr;
		socklen_t len = sizeof(ac_addr);

		int client = accept(sock, (sockaddr*)&ac_addr, &len); //返回 connect socket 
		if (client < 0) break;
		printf("client socket %d \n", client);
		printf("addr is %s\n", (char*)(inet_ntoa(ac_addr.sin_addr))); //inet_ntoa是将ip地址转换成“.”点隔的字符串格式
		printf("port = %d \n", ntohs(ac_addr.sin_port));

		//实现多线程
		TcpThread* th = new TcpThread();
		th->client = client;
		std::thread sth(&TcpThread::Main, th);  //创建线程  参数作何解？？
		sth.detach();  //从状态上实现线程分离
	}
	closesocket(sock);

	return 0;
}