ошибка при компелировании

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
 
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
 
///   SERVER   
 
int main(int argc, char *argv[])
{
    //Declaring process variables.
    int server_sockfd, client_sockfd;
    int server_len ; 
    int rc ; 
    unsigned client_len;
    struct sockaddr_in server_address;
    struct sockaddr_in client_address;
 
    //Remove any old socket and create an unnamed socket for the server.
 
    server_sockfd = socket(AF_INET, SOCK_STREAM, 0);
    server_address.sin_family = AF_INET;
    server_address.sin_addr.s_addr = htons(INADDR_ANY);
    server_address.sin_port = htons(7734) ; 
    server_len = sizeof(server_address);
 
    rc = bind(server_sockfd, (struct sockaddr *) &server_address, server_len);  
 
    //Create a connection queue and wait for clients
    rc = listen(server_sockfd, 5);
 
    client_len = sizeof(client_address);
    client_sockfd = accept(server_sockfd, (struct sockaddr *) &client_address, &client_len);
    
    char mes[]="Server to Client:  ";
    char mes2[100];
    char buf[50];
    rc=read(client_sockfd,&buf,50);
    printf("%s\n",buf); 
    strcpy(mes2,buf);
    close(client_sockfd);
int client_sockfd2;
listen(client_sockfd,5);
client_sockfd2 = accept(server_sockfd, (struct sockaddr *) &client_address, &client_len);
    rc=write(client_sockfd2,&mes2,50);
    printf("server exiting\n");
 
    //close(client_sockfd);
    close(client_sockfd2);
    return 0;
}