udp 广播通讯

send:
WSADATA wsaData; //指向WinSocket信息结构的指针
SOCKET sockListener;
SOCKADDR_IN sin,saUdpServ;
BOOL fBroadcast = TRUE;
char sendBuff[1024];
int nSize;
int ncount=0;
if(WSAStartup(MAKEWORD( 1, 1 ), &wsaData )!=0)//进行WinSocket的初始化
{
printf("Can't initiates windows socket!Program stop./n");//初始化失败返回-1
return -1;
}
sockListener=socket(PF_INET,SOCK_DGRAM,0);
setsockopt ( sockListener,SOL_SOCKET,SO_BROADCAST,
(CHAR *)&fBroadcast,sizeof ( BOOL ));

sin.sin_family = AF_INET;
sin.sin_port = htons(0);
sin.sin_addr.s_addr = htonl(INADDR_ANY);
if(bind( sockListener, (SOCKADDR *)&sin, sizeof(sin))!=0)
{
printf("Can't bind socket to local port!Program stop./n");//初始化失败返回-1
return -1;
}
saUdpServ.sin_family = AF_INET;
saUdpServ.sin_addr.s_addr = htonl ( INADDR_BROADCAST );
saUdpServ.sin_port = htons (7001);//发送用的端口，可以根据需要更改
nSize = sizeof ( SOCKADDR_IN );
while(1)
{
sprintf(sendBuff,"Message %d",ncount++);
sendto ( sockListener,sendBuff,
lstrlen (sendBuff),
0,
(SOCKADDR *) &saUdpServ,
sizeof ( SOCKADDR_IN ));
printf("%s/n",sendBuff);
}

receive:
WSADATA wsaData; //指向WinSocket信息结构的指针
SOCKET sockListener;
SOCKADDR_IN sin,saClient;
char cRecvBuff[1024];
int nSize,nbSize;
int iAddrLen=sizeof(saClient);
if(WSAStartup(MAKEWORD( 1, 1 ), &wsaData )!=0)//进行WinSocket的初始化
{
printf("Can't initiates windows socket!Program stop./n");//初始化失败返回-1
return -1;
}
sockListener=socket(AF_INET, SOCK_DGRAM,0);
sin.sin_family = AF_INET;
sin.sin_port = htons(7001);//发送端使用的发送端口，可以根据需要更改
sin.sin_addr.s_addr = htonl(INADDR_ANY);
if(bind( sockListener, (SOCKADDR FAR *)&sin, sizeof(sin))!=0)
{
printf("Can't bind socket to local port!Program stop./n");//初始化失败返回-1
return -1;
}
while(1)
{
nSize = sizeof ( SOCKADDR_IN );
if((nbSize=recvfrom (sockListener,cRecvBuff,1024,0,
(SOCKADDR FAR *) &saClient,&nSize))==SOCKET_ERROR)
{
printf("Recive Error");
break;
}
cRecvBuff[nbSize] = '/0';
printf("%s/n",cRecvBuff);
}