UDP example anyone?

here is:

# include <sys/types.h># include <sys/socket.h># include <arpa/inet.h># include <stdio.h>

int main(int argc, char **argv)

{

struct sockaddr_in peeraddr, /*IP and socke port*/

localaddr;/*local socket address*/

int sockfd;

char recmsg[BUFLEN+1];

int socklen, n;

if(argc!=5){

printf("%s <dest IP address> <dest port> <source IP address> <source port>\n", argv [0]);

exit(0);

}

sockfd = socket(AF_INET, SOCK_DGRAM, 0);

if(sockfd<0){

printf("socket creating err in udptalk\n");

exit(1);

}

socklen = sizeof(struct sockaddr_in);

memset(&peeraddr, 0, socklen);

peeraddr.sin_family=AF_INET;

peeraddr.sin_port=htons(atoi(argv[2]));

if(inet_pton(AF_INET, argv[1], &peeraddr.sin_addr)<=0){

printf("Wrong dest IP address!\n");

exit(0);

}

memset(&localaddr, 0, socklen);

localaddr.sin_family=AF_INET;

if(inet_pton(AF_INET, argv[3], &localaddr.sin_addr)<=0){

printf("Wrong source IP address!\n");

exit(0);

}

localaddr.sin_port=htons(atoi(argv[4]));

if(bind(sockfd, &localaddr, socklen)<0){

printf("bind local address err in udptalk!\n");

exit(2);

}

if(fgets(recmsg, BUFLEN, stdin) == NULL) exit(0);

if(sendto(sockfd, recmsg, strlen(recmsg), 0, &peeraddr, socklen)<0){

printf("sendto err in udptalk!\n");

exit(3);

}

for(;;){

/*recv&send message loop*/

n = recvfrom(sockfd, recmsg, BUFLEN, 0, &peeraddr, &socklen);

if(n<0){

printf("recvfrom err in udptalk!\n");

exit(4);

}else{

recmsg[n]=0;

printf("peer:%s", recmsg);

}

if(fgets(recmsg, BUFLEN, stdin) == NULL) exit(0);

if(sendto(sockfd, recmsg, strlen(recmsg), 0, &peeraddr, socklen)<0){

printf("sendto err in udptalk!\n");

exit(3);

}

}

}

os: uclinux ,