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diff --git a/docs/tutorials/008/page03.html b/docs/tutorials/008/page03.html deleted file mode 100644 index 36c58e4d3c5..00000000000 --- a/docs/tutorials/008/page03.html +++ /dev/null @@ -1,145 +0,0 @@ -<HTML> -<HEAD> - <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"> - <TITLE>ACE Tutorial 008</TITLE> -</HEAD> -<BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#000FFF" VLINK="#FF0F0F"> - -<CENTER><B><FONT SIZE=+2>ACE Tutorial 008</FONT></B></CENTER> - -<CENTER><B><FONT SIZE=+2>Sending and receiving datagrams</FONT></B></CENTER> - - -<P> -<HR WIDTH="100%"> - - -<P>In <A HREF="directed_client.cpp">directed_client.cpp</A> we create a -client that knows how to send a datagram to a server on a known host. -This is a good thing if you know where the server lives and want to have -a conversation. The Unix <I>talk</I> utilitiy, for instance, -could be written this way. - -<P> -<HR WIDTH="100%"> -<PRE> -<font color=red>// $Id$</font> - -<font color=blue>#include</font> "<A HREF="../../../ace/SOCK_Dgram.h">ace/SOCK_Dgram.h</A>" -<font color=blue>#include</font> "<A HREF="../../../ace/INET_Addr.h">ace/INET_Addr.h</A>" - -<font color=red>/* Once again, we use the default server port. In a "<font color=green>real</font>" system, - the server's port (or ports) would be published in some way so that - clients would know where to "<font color=green>look</font>". We could even add entries to - the operating system's services file and use a service name instead - of a number. We'll come back to that in some other tutorial - though. For now, let's stay simple. */</font> -static const u_short PORT = ACE_DEFAULT_SERVER_PORT; - -<font color=red>/* Our goal here is to develop a client that can send a datagram to a - server running on a known host. We'll use a command-line argument - to specify the hostname instead of hard-coding it. */</font> -int -main (int argc,char *argv[]) -{ - <font color=red>/* All datagrams must have a point of origin. Since we intend to - transmit instead of receive, we initialize an address with zero - and let the OS choose a port for us. We could have chosen our own - value between 1025 and 65535 as long as it isn't already in use. - - The biggest difference between client and server when datagrams - are used is the fact that servers tend to have a known/fixed - address at which they listen and clients tend to have arbitrary - addresses assigned by the OS. */</font> - ACE_INET_Addr local((u_short) 0); - - <font color=red>/* And here is our datagram object. */</font> - ACE_SOCK_Dgram dgram; - - <font color=red>/* Notice that this looks a lot like the server application. - There's no difference in creating server datagrams an client - datagrams. You can even use a zero-constructed address for your - server datagram as long as you tell the client where you're - listening (eg -- by writting into a file or some such). */</font> - if (dgram.open (local) == -1) - ACE_ERROR_RETURN ((LM_ERROR, - "<font color=green>%p\n</font>", - "<font color=green>datagram open</font>"), - -1); - - <font color=red>/* Yep. We've seen this before too... */</font> - char buf[BUFSIZ]; - - <font color=red>/* Ok, now we're doing something different. */</font> - sprintf (buf, "<font color=green>Hello World!</font>"); - - <font color=red>/* Just like sending a telegram, we have to address our datagram. - Here, we create an address object at the desired port on the - chosen host. To keep us from crashing, we'll provide a default - host name if we aren't given one. */</font> - ACE_INET_Addr remote (PORT, - argc > 1 ? argv[1] : "<font color=green>localhost</font>"); - - ACE_DEBUG ((LM_DEBUG, - "<font color=green>(%P|%t) Sending (%s) to the server.\n</font>", - buf)); - <font color=red>/* Now we send our buffer of stuff to the remote address. This is - just exactly what the server did after receiving a client message. - Datagrams are rather orthogonal that way: they don't generally - make much of a fuss about being either client or server. */</font> - if (dgram.send (buf, - <font color=#008888>ACE_OS::strlen</font> (buf) + 1, - remote) == -1) - ACE_ERROR_RETURN ((LM_ERROR, - "<font color=green>%p\n</font>", - "<font color=green>send</font>"), - -1); - - <font color=red>/* Now we've turned around and put ourselves into "<font color=green>server mode</font>" by - invoking the recv() method. We know our server is going to send - us something, so we hang out here and wait for it. Because we - know datagrams are unreliable, there is a chance that the server - will respond but we won't hear. You might consider providing a - timeout on the recv() in that case. If recv() fails due to - timeout it will return -1 and you can then resend your query and - attempt the recv() again. - - Like the server application, we have to give the recv() an - uninitialized addr object so that we can find out who is talking - back to us. */</font> - if (dgram.recv (buf, - sizeof (buf), - remote) == -1) - ACE_ERROR_RETURN ((LM_ERROR, - "<font color=green>%p\n</font>", - "<font color=green>recv</font>"), - -1); - - <font color=red>/* Find out what the server had to say. */</font> - ACE_DEBUG ((LM_DEBUG, - "<font color=green>(%P|%t) The server said: %s\n</font>", - buf)); - - <font color=red>/* Using the "<font color=green>remote</font>" object instance, find out where the server - lives. We could then save this address and use directed datagrams - to chat with the server for a while. */</font> - ACE_DEBUG ((LM_DEBUG, - "<font color=green>(%P|%t) The server can be found at: (%s:%d)\n</font>", - remote.get_host_name(), - PORT)); - - return 0; -} -</PRE> -<HR WIDTH="100%"> - -<P>That's all neat and good but the point of what we're doing here is not -to talk to a server we know about but to discover servers we don't know -about. Now, you could send a directed datagram to every possible -host address on your network but that's not a very nice thing to do. -On the next page, we'll find out the right approach... - -<P><HR WIDTH="100%"> -<CENTER>[<A HREF="../online-tutorials.html">Tutorial Index</A>] [<A HREF="page04.html">Continue This Tutorial</A>]</CENTER> |