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<h4 class="subsection">16.9.6 Byte Stream Socket Example</h4>

<p>Here is an example client program that makes a connection for a byte
stream socket in the Internet namespace.  It doesn't do anything
particularly interesting once it has connected to the server; it just
sends a text string to the server and exits.

   <p>This program uses <code>init_sockaddr</code> to set up the socket address; see
<a href="Inet-Example.html#Inet-Example">Inet Example</a>.

<pre class="smallexample">     #include &lt;stdio.h&gt;
     #include &lt;errno.h&gt;
     #include &lt;stdlib.h&gt;
     #include &lt;unistd.h&gt;
     #include &lt;sys/types.h&gt;
     #include &lt;sys/socket.h&gt;
     #include &lt;netinet/in.h&gt;
     #include &lt;netdb.h&gt;
     
     #define PORT            5555
     #define MESSAGE         "Yow!!! Are we having fun yet?!?"
     #define SERVERHOST      "mescaline.gnu.org"
     
     void
     write_to_server (int filedes)
     {
       int nbytes;
     
       nbytes = write (filedes, MESSAGE, strlen (MESSAGE) + 1);
       if (nbytes &lt; 0)
         {
           perror ("write");
           exit (EXIT_FAILURE);
         }
     }
     
     
     int
     main (void)
     {
       extern void init_sockaddr (struct sockaddr_in *name,
                                  const char *hostname,
                                  uint16_t port);
       int sock;
       struct sockaddr_in servername;
     
       /* <span class="roman">Create the socket.</span> */
       sock = socket (PF_INET, SOCK_STREAM, 0);
       if (sock &lt; 0)
         {
           perror ("socket (client)");
           exit (EXIT_FAILURE);
         }
     
       /* <span class="roman">Connect to the server.</span> */
       init_sockaddr (&amp;servername, SERVERHOST, PORT);
       if (0 &gt; connect (sock,
                        (struct sockaddr *) &amp;servername,
                        sizeof (servername)))
         {
           perror ("connect (client)");
           exit (EXIT_FAILURE);
         }
     
       /* <span class="roman">Send data to the server.</span> */
       write_to_server (sock);
       close (sock);
       exit (EXIT_SUCCESS);
     }
</pre>
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