Simple Socket Server Source Help!

[Elpin]

I have this C++ code:

int main( int argn, char **arg )
{
 int port = atoi( arg[ 1 ] );

 int sock_listen = socket( AF_INET, SOCK_STREAM, 0 );

 in_addr addr_any = { INADDR_ANY };
 sockaddr_in srv_addr;
 srv_addr.sin_family = AF_INET;
 srv_addr.sin_port = htons( port );
 srv_addr.sin_addr = addr_any;

 // set socket options to reuse address and port again in short time
 int opt = 1;
 setsockopt( sock_listen, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof( opt ) );

 // assign address and port to socket
 bind( sock_listen, (const sockaddr * ) &srv_addr, sizeof( srv_addr ) );

 listen( sock_listen, 1 );

 int sock_client = 0;

 // go!
 while ( 1 )
 {
     char buf[ 100 ];

     fd_set read_wait_set;
     // set all bits to zero
     FD_ZERO( &read_wait_set );

     // wait for stdin
     FD_SET( STDIN_FILENO, &read_wait_set );

     // select listen or client socket
     if ( sock_client )
         FD_SET( sock_client, &read_wait_set );
     else
         FD_SET( sock_listen, &read_wait_set );

     // wait for selected handles
     if ( select( MAX( sock_client, sock_listen ) + 1,
                          &read_wait_set, 0, 0, 0 &#41; < 0 &#41; break;

     // data on stdin?
     if &#40; FD_ISSET&#40; STDIN_FILENO, &read_wait_set &#41; &#41;
     &#123;
         //  read data from stdin
         int l = read&#40; STDIN_FILENO, buf, sizeof&#40; buf &#41; &#41;;
         if &#40; l < 0 &#41;
             printf&#40; "Unable to read data from stdin." &#41;;
         else
             printf&#40; "Got %d bytes from stdin.", l &#41;;

         // send data to client
         l = write&#40; sock_client, buf, l &#41;;
         if &#40; l < 0 &#41;
             printf&#40; "Unable send data to client." &#41;;
         else
             printf&#40; "Sent %d bytes to client.", l &#41;;
     &#125;

     // new connection form client?
     else if &#40; FD_ISSET&#40; sock_listen, &read_wait_set &#41; &#41;
     &#123;
         sockaddr_in rsa;
         int rsa_size = sizeof&#40; rsa &#41;;

         // accept connection from client
         sock_client = accept&#40; sock_listen, &#40; sockaddr * &#41; &rsa, &#40; socklen_t * &#41; &rsa_size &#41;;

         uint lsa = sizeof&#40; srv_addr &#41;;

         // get my identification
         getsockname&#40; sock_client, &#40; sockaddr * &#41; &srv_addr, &lsa &#41;;
     
         // get client info
         getpeername&#40; sock_client, &#40; sockaddr * &#41; &srv_addr, &lsa &#41;;

         printf&#40; "Peer name&#58; '%s'  port&#58; %d",
                  inet_ntoa&#40; srv_addr.sin_addr &#41;, ntohs&#40; srv_addr.sin_port &#41; &#41;;

         printf&#40; "Enter 'quit' to quit server." &#41;;
     &#125;

     // data from client?
     else if &#40; FD_ISSET&#40; sock_client, &read_wait_set &#41; &#41;
     &#123;
         // read data from socket
         int l = read&#40; sock_client, buf, sizeof&#40; buf &#41; &#41;;
         if &#40; !l &#41;
         &#123;
             printf&#40; "Client close socket." &#41;;
             close&#40; sock_client &#41;;
             sock_client = 0;
             break;
         &#125;
         else if &#40; l < 0 &#41;
             printf&#40; "Unable to read data from socket." &#41;;
         else
             printf&#40; "Read %d bytes from socket.", l &#41;;

         // send all data to stdout
         l = write&#40; STDOUT_FILENO, buf, l &#41;;

         // check, if client ask to close connection
         if &#40; !strncasecmp&#40; buf, "close", 5 &#41; &#41;
         &#123;
            printf&#40; "Client sent 'close' request, connection closed." &#41;;
            printf&#40; "Now wait for new client." &#41;;
             close&#40; sock_client &#41;;
             sock_client = 0;
         &#125;
     &#125;

     // quit request from server or client
     if &#40; !strncasecmp&#40; buf, "quit", 4 &#41; &#41;
     &#123;
         close&#40; sock_client &#41;;
         printf&#40; "Quit request entered... exiting now...\n" &#41;;
         break;
     &#125;
 &#125;

 close&#40; sock_listen &#41;;

 return 0;
&#125;

It is a socket server. It accepts a connection from client and prints on the console a message that client writes. What i need it to do, is accept connections from many clients at once. When a client write something, server prints it and when server write a message, all clients print it.
So far i have figured that i need to place "int pid = fork()" line after accept() function and let the parent process handle accepting connections and child handle the rest, but i still cant make it right!
Could you please help me? Thanks for any answer!

[scm]

So far i have figured that i need to place "int pid = fork()" line after accept() function and let the parent process handle accepting connections and child handle the rest, but i still cant make it right!

No, you let the child process the accept():

    for (;;)                            /* loop for connections */
    {
        if &#40;&#40;t= accept&#40;s, NULL, NULL&#41;&#41; < 0&#41; /* get a connection */
        &#123;
          if &#40;errno == EINTR&#41;           /* EINTR might happen on accept&#40;&#41;, */
            continue;                   /* try again */
          perror&#40;"accept"&#41;;             /* bad */
          exit&#40;1&#41;;
        &#125;
        switch&#40;fork&#40;&#41;&#41; &#123;                /* try to handle connection */
        case -1 &#58;                       /* bad news.  scream and die */
            perror&#40;"fork"&#41;;
            close&#40;s&#41;;
            close&#40;t&#41;;
            exit&#40;1&#41;;
        case 0 &#58;                        /* we're the child, do something */
            close&#40;s&#41;;
            do_something&#40;t&#41;;
            exit&#40;0&#41;;
        default &#58;                       /* we're the parent so look for */
            close&#40;t&#41;;                   /* another connection */
            continue;
        &#125;
    &#125;

[cbogdan]

Your queue length of pending client connections is 1; extend it with listen():

listen(sock_listen, n), where n is number of connections allowed on the incoming queue ( max n = SOMAXCONN ).