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diff --git a/docs/tutorials/001/page02.html b/docs/tutorials/001/page02.html index 5f4ca811e83..f5979936078 100644 --- a/docs/tutorials/001/page02.html +++ b/docs/tutorials/001/page02.html @@ -1,121 +1,137 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> <HTML> <HEAD> - <TITLE>ACE Tutorial 001</TITLE> - <META NAME="GENERATOR" CONTENT="Mozilla/3.01Gold (Win95; I) [Netscape]"> + <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> + <META NAME="GENERATOR" CONTENT="Mozilla/4.04 [en] (X11; I; Linux 2.0.32 i486) [Netscape]"> <META NAME="Author" CONTENT="James CE Johnson"> <META NAME="Description" CONTENT="A first step towards using ACE productively"> + <TITLE>ACE Tutorial 001</TITLE> </HEAD> -<BODY text = "#000000" link="#000fff" vlink="#ff0f0f" bgcolor="#ffffff"> +<BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#000FFF" VLINK="#FF0F0F"> + +<CENTER><B><FONT SIZE=+2>ACE Tutorial 001</FONT></B></CENTER> +<CENTER><B><FONT SIZE=+2>A Beginners Guide to Using the ACE Toolkit</FONT></B></CENTER> -<CENTER><P><B><FONT SIZE=+2>ACE Tutorial 001<BR> -A Beginners Guide to Using the ACE Toolkit</FONT></B></P></CENTER> <P> -<HR WIDTH="100%"></P> +<HR WIDTH="100%"> <P>From here, I want to move on to the main program loop. In a way, we're starting at the final product when we do this, but it is a very simple -piece of code and a good place to start.</P> +piece of code and a good place to start. -<P>The main program is really quite simple. The real work is done in the -ACE derived classes.</P> - -<UL> -<PRE>1. #include "acceptor.h" +<P>The <A HREF="server.cpp">main</A> +program is really quite simple. The real work is done in the ACE derived +classes. -2. ACE_Reactor g_reactor; - -3. const unsigned int PORT = 10000; - -4. main() +<P> +<HR WIDTH="100%"> +<PRE>/* + Include the header file where our client acceptor is defined. + */ +#include "ace/Reactor.h" + +/* + For simplicity, we create our reactor in the global address space. + In later tutorials we will do something more clever and appropriate. However, + the purpose of this tutorial is to introduce a connection acceptance and + handling, not the full capabilities of a reactor. +*/ +ACE_Reactor * g_reactor; + +/* + Include the header where we define our acceptor object. An acceptor is + an abstraction that allows a server to "accept" connections from clients. +*/ +#include "acceptor.h" + +/* + A TCP/IP server can listen to only one port for connection requests. + Well-known services can always be found at the same address. Lesser-known + services are generally told where to listen by a configuration file or + command-line parameter. For this example, we're satisfied with simply hard-coding + a random but known value. +*/ +static const u_short PORT = ACE_DEFAULT_SERVER_PORT; + +int main (int, char **) { - 5. ACE_INET_Addr addr(PORT); - - 6. Client_Acceptor * ca = new Client_Acceptor(addr); - - 7. g_reactor.register_handler(ca,ACE_Event_Handler::READ_MASK); - - 8. for(;;) g_reactor.handle_events(); - - 9. return(0); -} -</PRE> -</UL> - -<P>Here's a blow-by-blow account of what's being done:</P> - -<OL> -<LI>Include the header file where our client acceptor is defined.</LI> - -<LI>For simplicity, we create our reactor in the global address space. -In later tutorials we will do something more clever and appropriate. However, -the purpose of this tutorial is to introduce a connection acceptance and -handling, not the full capabilities of a reactor.</LI> - -<LI>A TCP/IP server can listen to only one <I>port </I>for connection requests. -Well-known services can always be found at the same address. Lesser-known -services are generally told where to listen by a configuration file or -command-line parameter. For this example, we're satisfied with simply hard-coding -a random but known value.</LI> - -<LI>Define the program entry point. Obviously, we are ignoring any command -line parameters at this point. We may explore other options later.</LI> - -<LI>Like the Reactor, I'm skimming over the details of the <I>ADDR</I> -object. What it provides is an abstraction for addressing services in the -network. All we need to know at this point is that we are creating an address -object which specifies the TCP/IP <I>port</I> on which the server -will listen for new connection requests.</LI> - -<LI>Using the address object created above, we now create an acceptor object. -This is all it takes to create the TCP/IP server and get it ready -to listen on the specified port. As I understand it, no connections will -yet be established because the object isn't "open for business" -at this time. Which brings us to the next line...</LI> - -<LI>where the acceptor object is registered with the reactor. Upon registration, -the reactor <I>open</I>s the object. For an acceptor, this means that client -requests for connection will now be allowed. In the registration, we also -tell the reactor that we are interested in <I>read</I> events. A read event -for an acceptor is a request for connection. When the reactor sees one -of these events, it will invoke the <I>handle_input</I> member function -of the acceptor object. The <I>handle_input</I> function will then do whatever -is necessary to deal with the new connection request. This is discussed -in detail on the next page of this tutorial.</LI> - -<LI>The reactor's <I>handle_events</I> member function is responsible for -looking at all registered objects and invoking their member function when -anything of interest occurs. When an event is processed, the <I>handle_events -</I>function returns. In order to get all events, we embed this in an infinite -loop.</LI> - -<LI>This is redundant since the <I>handle_events</I> infinite loop will -never exit. Some compilers will complain if it isn't there though, so in -it goes.</LI> -</OL> - -<P>As I said, the main program is really quite simple:</P> - + /* + Create a Reactor instance. Again, a global pointer isn't exactly the + best way to handle this but for the simple example here, it will be OK. + We'll get cute with it later. + */ + g_reactor = new ACE_Reactor; + + /* + Like the Reactor, I'm skimming over the details of the ADDR + object. What it provides is an abstraction for addressing services in the + network. All we need to know at this point is that we are creating an address + object which specifies the TCP/IP port on which the server + will listen for new connection requests. + */ + ACE_INET_Addr addr (PORT); + + /* + We now create an acceptor object. No connections will + yet be established because the object isn't "open for business" + at this time. Which brings us to the next line... + */ + Logging_Acceptor * peer_acceptor = new Logging_Acceptor(); + + /* + where the acceptor object is opened. You'll find that most ACE + objects have to be open()ed before they're of any use to you. + On this open() call, we're telling the acceptor where to listen + for connections via the 'addr' object. We're also telling it + that we want it to be registered with our 'g_reactor' instance. + */ + if (peer_acceptor->open(addr,g_reactor) == -1 ) + ACE_ERROR_RETURN ((LM_ERROR, "Opening Acceptor\n"), -1); + + ACE_DEBUG ((LM_DEBUG, "(%P|%t) starting up server logging daemon\n")); + + /* + The reactor's handle_events member function is responsible for looking at + all registered objects and invoking an appropriate member function when + anything of interest occurs. When an event is processed, the handle_events + function returns. In order to get all events, we embed this in an infinite + loop. + + Since we put ourselves into an infinite loop, you'll need to CTRL-C + to exit the program. + */ + while (1) + g_reactor-> handle_events (); + + return 0; +}</PRE> + +<HR WIDTH="100%"> + +<P>As I said, the main program is really quite simple: <UL> -<LI>Create an address for the <I>port</I> we want to listen to</LI> +<LI> +Create an address for the <I>port</I> we want to listen to</LI> -<LI>Create an acceptor which listens on that address</LI> +<LI> +Create an acceptor which listens on that address</LI> -<LI>Register the acceptor with a reactor to respond to the connection requests</LI> +<LI> +Register the acceptor with a reactor to respond to the connection requests</LI> -<LI>Enter an infinite loop to let the reactor handle the events</LI> +<LI> +Enter an infinite loop to let the reactor handle the events</LI> </UL> - -<P>On the next page, we will take a look at the acceptor and how it responds -to new connection requests.</P> +On the next page, we will take a look at the acceptor and how it responds +to new connection requests. <P> -<HR WIDTH="100%"></P> - -<CENTER><P>[<A HREF="..">Tutorial Index</A>] [<A HREF="page01.html">Previous -Page</A>] [<A HREF="page03.html">Continue This Tutorial</A>] </P></CENTER> +<HR WIDTH="100%"> +<CENTER>[<A HREF="..">Tutorial +Index</A>] [<A HREF="page01.html">Previous +Page</A>] [<A HREF="page03.html">Continue +This Tutorial</A>]</CENTER> </BODY> </HTML> |