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<h1 class="topictitle1">Example: Generic client</h1>
<div><p>This code example contains the code for a common client job.</p>
<div class="section"><p>The client job does a <span class="apiname">socket()</span>, <span class="apiname">connect()</span>, <span class="apiname">send()</span>, <span class="apiname">recv()</span>, and <span class="apiname">close()</span> operation. The client job is not aware that
the data buffer it sent and received is going to a worker job rather than
the server. If you want to create a client application that works whether
the server uses the AF_INET address family or AF_INET6 address family, use
the IPv4 or IPv6 client example.</p>
</div>
<div class="section"><p>This client job works with each of these common connection-oriented
server designs:</p>
</div>
<div class="section"><ul><li>An iterative server. See <a href="xiterative.htm#xiterative">Example:
Write an iterative server program</a> for a sample program.</li>
<li>A spawn server and worker. See <a href="xspawn.htm#xspawn">Example:
Use the spawn() API to create child processes</a> for a sample program.</li>
<li>A sendmsg() server and rcvmsg() worker. See <a href="x1descriptors.htm#x1descriptors">Example:
Server program used for sendmsg() and recvmsg()</a> for a sample program.</li>
<li>A multiple accept() design. See <a href="x1mulitaccept.htm#x1mulitaccept">Example:
Server program to create a pool of multiple accept() worker jobs </a> for
a sample program.</li>
<li>A nonblocking I/O and select() design. See <a href="xnonblock.htm#xnonblock">Example:
Nonblocking I/O and select()</a> for a sample program.</li>
<li>A server that accepts connections from either an IPv4 or IPv6 client..
See <a href="xacceptboth.htm#xacceptboth">Example: Accept connections
from both IPv6 and IPv4 clients</a> for a sample program.</li>
</ul>
</div>
<div class="section"><h4 class="sectiontitle">Socket flow of events: Generic client</h4><p>The following
sample program uses the following sequence of function calls: </p>
<ol><li>The <span class="apiname">socket()</span> function returns a socket descriptor representing
an endpoint. The statement also identifies that the INET (Internet Protocol)
address family with the TCP transport (SOCK_STREAM) being used for this socket.</li>
<li>After the socket descriptor is received, the <span class="apiname">connect()</span> function
is used to establish a  connection to the server.</li>
<li>The <span class="apiname">send() </span> function sends data buffer
to the worker job(s). </li>
<li>The <span class="apiname">recv()</span> function receives data buffer from the worker
job(s).</li>
<li> The <span class="apiname">close()</span> function closes any open socket descriptors.</li>
</ol>
</div>
<div class="section"><div class="note"><span class="notetitle">Note:</span> By using the code examples, you agree to the terms of the <a href="codedisclaimer.htm">Code license and disclaimer information</a>.</div>
<pre>/**************************************************************************/
/* Generic client example is used with connection-oriented server designs */
/**************************************************************************/
#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;sys/socket.h&gt;
#include &lt;netinet/in.h&gt;

#define SERVER_PORT  12345

main (int argc, char *argv[])
{
   int    len, rc;
   int    sockfd;
   char   send_buf[80];
   char   recv_buf[80];
   struct sockaddr_in   addr;

   /*************************************************/
   /* Create an AF_INET stream socket               */
   /*************************************************/
   sockfd = socket(AF_INET, SOCK_STREAM, 0);
   if (sockfd &lt; 0)
   {
      perror("socket");
      exit(-1);
   }

   /*************************************************/
   /* Initialize the socket address structure       */
   /*************************************************/
   memset(&amp;addr, 0, sizeof(addr));
   addr.sin_family      = AF_INET;
   addr.sin_addr.s_addr = htonl(INADDR_ANY);
   addr.sin_port        = htons(SERVER_PORT);

   /*************************************************/
   /* Connect to the server                         */
   /*************************************************/
   rc = connect(sockfd,
                (struct sockaddr *)&amp;addr,
                sizeof(struct sockaddr_in));
   if (rc &lt; 0)
   {
      perror("connect");
      close(sockfd);
      exit(-1);
   }
   printf("Connect completed.\n");

   /*************************************************/
   /* Enter data buffer that is to be sent          */
   /*************************************************/
   printf("Enter message to be sent:\n");
   gets(send_buf);

   /*************************************************/
   /* Send data buffer to the worker job            */
   /*************************************************/
   len = send(sockfd, send_buf, strlen(send_buf) + 1, 0);
   if (len != strlen(send_buf) + 1)
   {
      perror("send");
      close(sockfd);
      exit(-1);
   }
   printf("%d bytes sent\n", len);

   /*************************************************/
   /* Receive data buffer from the worker job       */
   /*************************************************/
   len = recv(sockfd, recv_buf, sizeof(recv_buf), 0);
   if (len != strlen(send_buf) + 1)
   {
      perror("recv");
      close(sockfd);
      exit(-1);
   }
   printf("%d bytes received\n", len);

   /*************************************************/
   /* Close down the socket                         */
   /*************************************************/
   close(sockfd);
}</pre>
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<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="xcodesigns.htm" title="There are a number of ways that you can design a connection-oriented socket server on the iSeries. These example programs can be used to create your own connection-oriented designs.">Examples: Connection-oriented designs</a></div>
</div>
<div class="relref"><strong>Related reference</strong><br />
<div><a href="xip6client.htm" title="This sample program can be used with the server application that accepts requests from either IPv4 or IPv6 clients.">Example: IPv4 or IPv6 client</a></div>
<div><a href="xcodesigns.htm" title="There are a number of ways that you can design a connection-oriented socket server on the iSeries. These example programs can be used to create your own connection-oriented designs.">Examples: Connection-oriented designs</a></div>
<div><a href="xiterative.htm" title="Use this example to create a single server job that handles all incoming connections. When the accept() API is completed, the server handles the entire transaction.">Example: Write an iterative server program</a></div>
<div><a href="xdescriptors.htm" title="The sendmsg() and recvmsg() examples show how to design a server program that uses these APIs to handle incoming connections.">Example: Pass descriptors between processes</a></div>
<div><a href="x1descriptors.htm" title="This example shows how to use the sendmsg() API to create a pool of worker jobs.">Example: Server program used for sendmsg() and recvmsg()</a></div>
<div><a href="xmultiaccept.htm" title="These examples show how to design a server program that uses the multiple accept() model for handling incoming connection requests.">Examples: Use multiple accept() APIs to handle incoming requests</a></div>
<div><a href="x1mulitaccept.htm" title="This example shows how to use the multiple accept() model to create a pool of worker jobs.">Example: Server program to create a pool of multiple accept() worker jobs</a></div>
<div><a href="xasynchi0.htm" title="An application creates an I/O completion port using the QsoCreateIOCompletionPort() API.">Example: Use asynchronous I/O</a></div>
<div><a href="xnonblock.htm" title="This sample program uses nonblocking and the select() API.">Example: Nonblocking I/O and select()</a></div>
</div>
<div class="relinfo"><strong>Related information</strong><br />
<div><a href="../apis/socket.htm">socket()</a></div>
<div><a href="../apis/connec.htm">connect()</a></div>
<div><a href="../apis/close.htm">close()</a></div>
<div><a href="../apis/send.htm">send()</a></div>
<div><a href="../apis/recv.htm">recv()</a></div>
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