正确使用UDP广播（C++代码）

相比TCP，UDP的优点是传输速度快且能对整个网络广播数据。但我以前在使用UDP整个网络广播数据的用法上，一直没能好好使用。这段时间，正好需要使用UDP的这个功能，因此经过摸索，得出了一种使用方法如下：（不一定是最好的，但能实现我的功能）

// 服务器端// Server.cpp : Defines the entry point for the console application.//#include "stdafx.h"#include <WinSock2.h>#include <stdio.h>#include <iostream>using namespace std;#pragma comment(lib, "ws2_32.lib")const int MAX_BUF_LEN = 255;int _tmain(int argc, _TCHAR* argv[]){WORD wVersionRequested;WSADATA wsaData;int err;// 启动socket apiwVersionRequested = MAKEWORD( 2, 2 );err = WSAStartup( wVersionRequested, &wsaData );if ( err != 0 ){return -1;}if ( LOBYTE( wsaData.wVersion ) != 2 ||HIBYTE( wsaData.wVersion ) != 2 ){WSACleanup( );return -1; }// 创建socketSOCKET connect_socket;connect_socket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);if(INVALID_SOCKET == connect_socket){err = WSAGetLastError();printf("/"socket/" error! error code is %d/n", err);return -1;}SOCKADDR_IN sin;sin.sin_family = AF_INET;sin.sin_port = htons(3779);sin.sin_addr.s_addr = INADDR_BROADCAST;bool bOpt = true;//设置该套接字为广播类型setsockopt(connect_socket, SOL_SOCKET, SO_BROADCAST, (char*)&bOpt, sizeof(bOpt));int nAddrLen = sizeof(SOCKADDR);char buff[MAX_BUF_LEN] = "";int nLoop = 0;while(1){nLoop++;sprintf(buff, "%8d", nLoop);// 发送数据int nSendSize = sendto(connect_socket, buff, strlen(buff), 0, (SOCKADDR*)&sin, nAddrLen);if(SOCKET_ERROR == nSendSize){err = WSAGetLastError();printf("/"sendto/" error!, error code is %d/n", err);return -1;}printf("Send: %s/n", buff);Sleep(500);}return 0;}// 客户端// Client.cpp : Defines the entry point for the console application.//#include "stdafx.h"#include <WinSock2.h>#include <stdio.h>#pragma comment(lib, "ws2_32.lib")const int MAX_BUF_LEN = 255;int _tmain(int argc, _TCHAR* argv[]){WORD wVersionRequested;WSADATA wsaData;int err;// 启动socket apiwVersionRequested = MAKEWORD( 2, 2 );err = WSAStartup( wVersionRequested, &wsaData );if ( err != 0 ){return -1;}if ( LOBYTE( wsaData.wVersion ) != 2 ||HIBYTE( wsaData.wVersion ) != 2 ){WSACleanup( );return -1; }// 创建socketSOCKET connect_socket;connect_socket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);if(INVALID_SOCKET == connect_socket){err = WSAGetLastError();printf("/"socket/" error! error code is %d/n", err);return -1;}// 用来绑定套接字SOCKADDR_IN sin;sin.sin_family = AF_INET;sin.sin_port = htons(3779);sin.sin_addr.s_addr = 0;// 用来从网络上的广播地址接收数据SOCKADDR_IN sin_from;sin_from.sin_family = AF_INET;sin_from.sin_port = htons(3779);sin_from.sin_addr.s_addr = INADDR_BROADCAST;//设置该套接字为广播类型，bool bOpt = true;setsockopt(connect_socket, SOL_SOCKET, SO_BROADCAST, (char*)&bOpt, sizeof(bOpt));// 绑定套接字err = bind(connect_socket, (SOCKADDR*)&sin, sizeof(SOCKADDR));if(SOCKET_ERROR == err){err = WSAGetLastError();printf("/"bind/" error! error code is %d/n", err);return -1;}int nAddrLen = sizeof(SOCKADDR);char buff[MAX_BUF_LEN] = "";int nLoop = 0;while(1){// 接收数据int nSendSize = recvfrom(connect_socket, buff, MAX_BUF_LEN, 0, (SOCKADDR*)&sin_from, &nAddrLen);if(SOCKET_ERROR == nSendSize){err = WSAGetLastError();printf("/"recvfrom/" error! error code is %d/n", err);return -1;}buff[nSendSize] = '/0';printf("Recv: %s/n", buff);}return 0;}