c语言怎么加入组播组地址,加入一个组播组

#include "my_inet.h"

#include #define MAXBUF 256

#define PUERTO 5000

#define GRUPO "224.0.1.1"

int main(void)

{

int fd, n, r;

struct sockaddr_in srv, cli;

struct ip_mreq mreq;

char buf[MAXBUF];

memset( &srv, 0, sizeof(struct sockaddr_in) );

memset( &cli, 0, sizeof(struct sockaddr_in) );

memset( &mreq, 0, sizeof(struct ip_mreq) );

srv.sin_family = MY_AF_INET;

srv.sin_port = htons(PUERTO);

if( inet_aton(GRUPO, &srv.sin_addr ) < 0 ) {

perror("inet_aton");

return -1;

}

if( (fd = socket( MY_AF_INET, SOCK_DGRAM, MY_IPPROTO_UDP) ) < 0 ){

perror("socket");

return -1;

}

if( bind(fd, (struct sockaddr *)&srv, sizeof(srv)) < 0 ){

perror("bind");

return -1;

}

if (inet_aton(GRUPO, &