局域网广播的问题,只能在我本机上收到,广播信息,局域网中其他人收不到。局域网ip:192.168.11.3
网关:    192.168.11.254
具体代码如下:
发送端:#include<stdlib.h>
#include<iostream>
#include<stdio.h>
#include<conio.h>
#include<winsock2.h>
#include<windows.h>using namespace std;#pragma comment(lib,"ws2_32.lib")
void main()
{
SOCKET s;
sockaddr_in addrto;
WSADATA wsdata;
BOOL bsocket;
char *smsg="this is a test";
//启动SOCKET库,版本为2.0
WSAStartup(0x0202,&wsdata);

s=WSASocket(AF_INET,SOCK_DGRAM,0,NULL,0,WSA_FLAG_OVERLAPPED);
bsocket=TRUE;
    //然后赋值给地址,用来从网络上的广播地址接收消息;
addrto.sin_family=AF_INET;
    addrto.sin_addr.s_addr=INADDR_BROADCAST;
addrto.sin_port=htons(5050);
bool opt=true;
//设置该套接字为广播类型,
setsockopt(s,SOL_SOCKET,SO_BROADCAST,(char FAR *)&opt,sizeof(opt));
int nlen=sizeof(addrto);
while(1)
{
Sleep(1000);
//从广播地址发送消息
int ret=sendto(s,smsg,256,0,(sockaddr*)&addrto,nlen);
if(ret==SOCKET_ERROR)
cout<<WSAGetLastError()<<endl;
else
{
printf("ok");
}
}
}接收端:
#include<stdlib.h>
#include<iostream>
#include<conio.h>
#include<stdio.h>
#include<winsock2.h>
#include<windows.h>
#pragma comment(lib,"ws2_32.lib")using namespace std;
void main(void)
{
SOCKET s;
sockaddr_in from,a;
WSADATA wsdata;
BOOL optval;
//启动SOCKET库,版本为2.0
WSAStartup(0x0202,&wsdata);
optval=TRUE;
//然后赋值给两个地址,一个用来绑定套接字,一个用来从网络上的广播地址接收消息;
a.sin_family=AF_INET;
a.sin_addr.s_addr=0;
a.sin_port=htons(5050); from.sin_family=AF_INET;
from.sin_addr.s_addr=INADDR_BROADCAST;
from.sin_port=htons(5050);

int fromlength=sizeof(SOCKADDR);
//用UDP初始化套接字
s=socket(AF_INET,SOCK_DGRAM,0);

//设置该套接字为广播类型,
setsockopt(s,SOL_SOCKET,SO_BROADCAST,(char FAR *)&optval,sizeof(optval));
bind(s,(sockaddr *)&a,sizeof(sockaddr_in));
char buf[256];
while(1)
{
//从广播地址接收消息,注意用来绑定的地址和接收消息的地址是不一样的
recvfrom(s,buf,256,0,(struct sockaddr FAR *)&from,(int FAR *)&fromlength);
Sleep(2000);
printf("%s\n",buf);
ZeroMemory(buf,256);
}
}