problem about "undefined reference to"


I have a code shown below, but when I use “qcc -o udpclient udpclient.c” to compile the file, I was told:
udpclient.o: In function main': udpclient.o(.text+0x3a): undefined reference to socket’
udpclient.o(.text+0xb6): undefined reference to sendto' udpclient.o(.text+0xd1): undefined reference to recvfro
cc: /usr/qnx632/host/qnx6/x86/usr/bin/ntox86-ld error 1

Could some one help me?
Thanks in advance.

/* file: udpclient.c */
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

int main(int argc, char **argv)
int fd;
struct sockaddr_in address;
int address_len;
char line[80] = “Client to Server string!\n”;
int n;

fd = socket(AF_INET, SOCK_DGRAM, 0);
bzero(&address, sizeof(address));
address.sin_family = AF_INET;
address.sin_addr.s_addr = inet_addr(“”);
address.sin_port = htons(5000);
address_len = sizeof(address);

sendto(fd, line, strlen(line)+1, 0, (struct sockaddr *)&address, sizeof(address));
n = recvfrom(fd, line, 80, 0, NULL, NULL);
printf(“received %d:%s”, n, line);


qcc -lsocket 增加库。

Thanks a million, it works.