undefined reference to `writen'

Question

I am learning socket programming and currently working on an ECHO server code. I am getting these errors :

serverecho.c:(.text+0x173): undefined reference to 'writen'
serverecho.c:(.text+0x180): undefined reference to 'print'

while compiling. I am not sure what I have done wrong in this. My code's below:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>

#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>

#define SA  struct sockaddr
#define MAXLINE 4096

int main(int argc, char *argv[])
{
    int roockfd, confd;
    pid_t childpid;
    socklen_t len;
    char buff[MAXLINE];
    struct sockaddr_in servaddr, cliaddr;

    roockfd = socket(AF_INET, SOCK_STREAM, 0);

    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(13);
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);

    bind(roockfd, (SA *)&servaddr, sizeof(servaddr));

    listen(roockfd, 5);

    for (; ;) {
        len = sizeof(cliaddr);

        confd = accept(roockfd, (SA *)&cliaddr, &len);
        printf("Connection from %s, port %d\n",
        inet_ntop(AF_INET, &cliaddr.sin_addr, buff, sizeof(buff)),
                           ntohs(cliaddr.sin_port));
        if ((childpid=fork())==0)
        {   
            close(roockfd);
            echoserv(confd);
            exit(0);
        }

        close(confd);
    }
}

echoserv(int sockfd)   /* echoserv function */
{
    ssize_t n;
    char buff[MAXLINE];

again :
    while((n=read(sockfd,buff,MAXLINE)>0))
        writen(sockfd,buff,n);

        if(n<0)
            print("Error while reading");
}

Error while compiling with gcc :

root@kali:~/Desktop/cprogs# gcc serverecho.c -o serverecho.out -lm /tmp/ccWL7GLc.o: In function 'echoserv':
serverecho.c:(.text+0x173): undefined reference to 'writen'
serverecho.c:(.text+0x1b9): undefined reference to 'print'
collect2: error: ld returned 1 exit status

Answer 1

Use this:

write(sockfd,buff,n);

because writen is not a predefined function in C. So, when you compile your program, you are getting an undefined reference to `writen'.

Also do printf("Error while reading"); instead of print().