Linux系统下UDP发送和接收广播消息小例子

// 发送端

#include <iostream>

#include <stdio.h>

#include <sys/socket.h>

#include <unistd.h>

#include <sys/types.h>

#include <netdb.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <string.h>





using namespace std;



int main()

{

setvbuf(stdout, NULL, _IONBF, 0);

fflush(stdout);



int sock = -1;

if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)

{

cout<<"socket error"<<endl;

return false;

}



const int opt = 1;

//设置该套接字为广播类型，

int nb = 0;

nb = setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (char *)&opt, sizeof(opt));

if(nb == -1)

{

cout<<"set socket error..."<<endl;

return false;

}



struct sockaddr_in addrto;

bzero(&addrto, sizeof(struct sockaddr_in));

addrto.sin_family=AF_INET;

addrto.sin_addr.s_addr=htonl(INADDR_BROADCAST);

addrto.sin_port=htons(6000);

int nlen=sizeof(addrto);



while(1)

{

sleep(1);

//从广播地址发送消息

char smsg[] = {"abcdef"};

int ret=sendto(sock, smsg, strlen(smsg), 0, (sockaddr*)&addrto, nlen);

if(ret<0)

{

cout<<"send error...."<<ret<<endl;

}

else

{

printf("ok ");

}

}



return 0;

}



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// 接收端 http://blog.csdn.net/robertkun



#include <iostream>

#include <stdio.h>

#include <sys/socket.h>

#include <unistd.h>

#include <sys/types.h>

#include <netdb.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <string.h>





using namespace std;



int main()

{

setvbuf(stdout, NULL, _IONBF, 0);

fflush(stdout);



// 绑定地址

struct sockaddr_in addrto;

bzero(&addrto, sizeof(struct sockaddr_in));

addrto.sin_family = AF_INET;

addrto.sin_addr.s_addr = htonl(INADDR_ANY);

addrto.sin_port = htons(6000);



// 广播地址

struct sockaddr_in from;

bzero(&from, sizeof(struct sockaddr_in));

from.sin_family = AF_INET;

from.sin_addr.s_addr = htonl(INADDR_ANY);

from.sin_port = htons(6000);



int sock = -1;

if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)

{

cout<<"socket error"<<endl;

return false;

}



const int opt = 1;

//设置该套接字为广播类型，

int nb = 0;

nb = setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (char *)&opt, sizeof(opt));

if(nb == -1)

{

cout<<"set socket error..."<<endl;

return false;

}



if(bind(sock,(struct sockaddr *)&(addrto), sizeof(struct sockaddr_in)) == -1)

{

cout<<"bind error..."<<endl;

return false;

}



int len = sizeof(sockaddr_in);

char smsg[100] = {0};



while(1)

{

//从广播地址接受消息

int ret=recvfrom(sock, smsg, 100, 0, (struct sockaddr*)&from,(socklen_t*)&len);

if(ret<=0)

{

cout<<"read error...."<<sock<<endl;

}

else

{

printf("%s\t", smsg);

}



sleep(1);

}



return 0;

}