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<head>
<title>ACE Tutorial 022</title>
</head>
<BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#000FFF" VLINK="#FF0F0F">
<CENTER><B><FONT SIZE=+2>ACE Tutorial 022</FONT></B></CENTER>
We begin with <a href="server.cpp">server.cpp</a>
<UL>
<P>Abstract:
We begin with the server and the acceptor which we developed in
our ACE Tutorial 005. We modify these and add new
implementation files so as to make the acceptor service dynamically
(un)loadable. What we want to do is separate the implementation
of the service from its configuration. So, our server will
now just act as a daemon waiting for requests.
We again enroll the services of the ACE_Reactor to handle
events. Everything occurs in a single thread. <P>
This tutorial helps us learn apply the service configurator
pattern and make services dynamically configurable. In that
process, we are trying to make the acceptor we have developed
previously as a dynamically configurable service.
</UL>
<P>
<HR WIDTH="100%">
<P>
<PRE>
<font color=red>/* We try to keep the server much simpler than before and
remove any thing related to the acceptor from the main ().
This lets keep the server running irrespective of the
state of the acceptor service. */
</font>
<font color=red>/* As always, we would need the
ACE_Service_Config to help run the server as a daemon. */ </font>
<font color=blue>#include </font><font color=green>"ace/Service_Config.h"</font>
<font color=red>/* Since we are seperating the acceptor service class from the
server, we need to declare our Acceptor_Service */ </font>
<font color=blue>#include </font><font color=green>"Acceptor_Service.h"</font>
int
main (int argc, char *argv [])
{
<font color=red>
/* Perform daemon services update ... this opens the svc.conf
file and reads the entries present in the svc.conf
file. We will later learn the syntax of making an entry
into a svc.conf file. But for now, remember that this is a
file which has the entries to load or unload a service
dynamically or statically. */
In case, the function call returns a (-1), which is
indicative of an error, we print out a debug statement
and return (-1) to indicate an failure.</font>
if (ACE_Service_Config::open (argc,
argv,
ACE_DEFAULT_LOGGER_KEY,
0) == -1)
ACE_ERROR_RETURN ((LM_ERROR,
"%p\n",
"ACE_Service_Config::open"),
-1);
<font color=red>
/* Install our signal handler. As we already know, you can actually
register signal handlers with the reactor. You might do that
when the signal handler is responsible for performing "real"
work. Our simple flag-setter doesn't justify deriving from
ACE_Event_Handler and providing a callback function
though. */ </font>
ACE_Sig_Action sa ((ACE_SignalHandler) handler, SIGHUP);
<font color=red>
/* Start running the event loop so that it
listens for events and acts accordingly. This event loop will run
either the event loop is ended explicitly or an error
occurs. */ </font>
ACE_Reactor::run_event_loop ();
<font color=red>/* NOT REACHED */</font>
}
</PRE>
<P><HR WIDTH="100%">
<CENTER>[<A HREF="../online-tutorials.html">Tutorial Index</A>] [<A HREF="page03.html">Continue This Tutorial</A>]</CENTER>
<hr>
<address><a href="mailto:pgontla@ece.uci.edu">Priyanka Gontla</a></address>
<!-- Created: Thu Dec 28 15:17:34 PST 2000 -->
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Last modified: Sat Jan 20 10:19:22 CST 2001
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