c - Unable to connect with multiple client with my socket server program -

my socket server program mentioned below. works fine single client when try connect client @ same time, unable connect. have defined max_clients in program 2 still why unable connect multiple clients? correct process connect multiple client? able connect multiple client modifying code? possible fix?

socket server code:

#include <stdio.h> #include <stdlib.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <error.h> #include <strings.h> #include <unistd.h> #include <arpa/inet.h>  #define error -1 #define max_clients 2 #define max_data 1024     main (int argc, char **argv){       struct sockaddr_in server;     struct sockaddr_in client;     int sock;     int new;     int sockaddr_len = sizeof (struct sockaddr_in);     int data_len;     char data [max_data];       if ((sock = socket (af_inet, sock_stream, 0)) == -1)     {          perror ("socket: ");         exit (-1);      }        printf("after socket");     server.sin_family = af_inet;     server.sin_port = htons(atoi(argv[2]));     server.sin_addr.s_addr = inaddr_any;     bzero (&server.sin_zero, 8);     printf("after server");       if ((bind (sock, (struct sockaddr*)&server, sockaddr_len)) == -1)     {         perror  ("bind");         exit (-1);      }     printf("after bind");     if ((listen(sock, max_clients)) == error)     {         perror ("listen");         exit (-1);        }     printf("after listen");      while(1)      {         if ((new = accept(sock, (struct sockaddr*)&client, &sockaddr_len)) == error)         {               perror ("accept");             exit (-1);          }              printf("after new");             printf("new client connected port no %d , ip %s\n",ntohs(client.sin_port), inet_ntoa(client.sin_addr));             data_len = 1;             while (data_len)                 {                     data_len = recv (new, data, max_data, 0);                     if (data_len)                      {                         send (new, data, data_len, 0)   ;                         data [data_len]='\0';                         printf("sent mesg: %s", data);                     }                     printf("after datalen");                 }                 printf("client disconnected\n");                 close(new);         }         printf("after close new");         close (sock);      }  

your program single-threaded, , 1 thing @ time. when have accepted socket connection client (in outer while loop) start communicating client (in inner while loop), , don't accept call until first client has disconnected.

either use threads, 1 thread waits new connections , 1 additional thread each client, waiting input client, or use select call, lets wait input simultaneously several different sources.