Hi,
I tried to run the following code for performing multicast. This does not work on fedora box.
Could you let me know what could be the sources of error.

Awaiting your reply,
chev
-------------------------
/*
* listener.c -- joins a multicast group and echoes all data it receives from
* the group to its stdout...
*
* Antony Courtney, 25/11/94
* Modified by: Fréric Bastien (25/03/04)
* to compile without warning and work correctly
*/

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <time.h>
#include <string.h>
#include <stdio.h>

#define HELLO_PORT 12345
#define HELLO_GROUP "225.0.0.37"
#define MSGBUFSIZE 256

main(int argc, char *argv[])
{
struct sockaddr_in addr;
int fd, nbytes,addrlen;
struct ip_mreq mreq;
char msgbuf[MSGBUFSIZE];

u_int yes=1;

/* create what looks like an ordinary UDP socket */
if ((fd=socket(AF_INET,SOCK_DGRAM,0)) < 0) {
perror("socket");
exit(1);
}


/* allow multiple sockets to use the same PORT number */
if (setsockopt(fd,SOL_SOCKET,SO_REUSEADDR,&yes,sizeof (yes)) < 0) {
perror("Reusing ADDR failed");
exit(1);
}


/* set up destination address */
memset(&addr,0,sizeof(addr));
addr.sin_family=AF_INET;
addr.sin_addr.s_addr=htonl(INADDR_ANY); /* N.B.: differs from sender */
addr.sin_port=htons(HELLO_PORT);


/* bind to receive address */
if (bind(fd,(struct sockaddr *) &addr,sizeof(addr)) < 0) {
perror("bind");
exit(1);
}

/* use setsockopt() to request that the kernel join a multicast group */
mreq.imr_multiaddr.s_addr=inet_addr(HELLO_GROUP);
mreq.imr_interface.s_addr=htonl(INADDR_ANY);
if (setsockopt(fd,IPPROTO_IP,IP_ADD_MEMBERSHIP,&mreq, sizeof(mreq)) < 0) {
perror("setsockopt");
exit(1);
}

printf("\n reached the recvfrom statement...");
printf("\n reached the recvfrom statement...");

/* now just enter a read-print loop */
while (1) {
addrlen=sizeof(addr);
if ((nbytes=recvfrom(fd,msgbuf,MSGBUFSIZE,0,
(struct sockaddr *) &addr,&addrlen)) < 0) {
perror("recvfrom");
exit(1);
}
puts(msgbuf);
}
}

---------------------

/*
* sender.c -- multicasts "hello, world!" to a multicast group once a second
*
* Antony Courtney, 25/11/94
*/

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <time.h>
#include <string.h>
#include <stdio.h>


#define HELLO_PORT 12345
#define HELLO_GROUP "225.0.0.37"

main(int argc, char *argv[])
{
struct sockaddr_in addr;
int fd, cnt;
struct ip_mreq mreq;
char *message="Hello, World!";

/* create what looks like an ordinary UDP socket */
if ((fd=socket(AF_INET,SOCK_DGRAM,0)) < 0) {
perror("socket");
exit(1);
}


/* set up destination address */
memset(&addr,0,sizeof(addr));
addr.sin_family=AF_INET;
addr.sin_addr.s_addr=inet_addr(HELLO_GROUP);
addr.sin_port=htons(HELLO_PORT);

printf("\n Reached the sendto statement");
printf("\n Reached the sendto statement");

/* now just sendto() our destination! */
while (1) {
if (sendto(fd,message,sizeof(message),0,(struct sockaddr *) &addr,
sizeof(addr)) < 0) {
perror("sendto");
exit(1);
}
sleep(1);
}
}