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diff --git a/docs/tutorials/008/page04.html b/docs/tutorials/008/page04.html deleted file mode 100644 index faaaed77dce..00000000000 --- a/docs/tutorials/008/page04.html +++ /dev/null @@ -1,133 +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%"> - -In <A HREF="broadcast_client.cpp">broadcast_client.cpp</A> we -find out how to send a single datagram to every host on our (sub)network. -I have to say <I>(sub)network</I> because broadcast datagrams typically -are not passed through routers. So, if your network admin has divided -up your network into subnets, your broadcasts will likey stay on the -subnet you're a part of. - -<P>I've only commented the parts that are different from the directed_client. -<HR WIDTH="100%"> -<PRE> -<font color=red>// $Id$</font> - -<font color=blue>#include</font> "<A HREF="../../../ace/SOCK_Dgram_Bcast.h">ace/SOCK_Dgram_Bcast.h</A>" -<font color=blue>#include</font> "<A HREF="../../../ace/INET_Addr.h">ace/INET_Addr.h</A>" - -static const u_short PORT = ACE_DEFAULT_SERVER_PORT; - -int -main (int argc,char *argv[]) -{ - ACE_INET_Addr local ((u_short) 0); - - <font color=red>/* Instead of creating the ACE_SOCK_Dgram we created last time, - we'll create an ACE_SOCK_Dgram_Bcast. "<font color=green>Bcast</font>" means, of course, - "<font color=green>Broadcast</font>". This ACE object is clever enough to go out to the OS - and find all of the network interfaces. When you send() on a - Dgram_Bcast, it will send the datagram out on all of those - interfaces. This is quiet handy if you do it on a multi-homed - host that plays router... */</font> - ACE_SOCK_Dgram_Bcast dgram; - - if (dgram.open (local) == -1) - ACE_ERROR_RETURN ((LM_ERROR, - "<font color=green>%p\n</font>", - "<font color=green>datagram open</font>"), - -1); - - char buf[BUFSIZ]; - - sprintf (buf, "<font color=green>Hello World!</font>"); - - <font color=red>/* The only other difference between us and the directed client is - that we don't specify a host to receive the datagram. Instead, we - use the magic value "<font color=green>INADDR_BROADCAST</font>". All hosts are obliged to - respond to datagrams directed to this address the same as they - would to datagrams sent to their hostname. - - Remember, the Dgram_Bcast will send a datagram to all interfaces - on the host. That's true even if the address is for a specific - host (and the host address makes sense for the interface). The - real power is in using an INADDR_BROADCAST addressed datagram - against all interfaces. */</font> - - ACE_INET_Addr remote (PORT, - INADDR_BROADCAST); - - ACE_DEBUG ((LM_DEBUG, - "<font color=green>(%P|%t) Sending (%s) to the server.\n</font>", - buf)); - - 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); - - 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); - - 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> About that subnet thing: -<BLOCKQUOTE>If you run this client on a host that has multiple network -interfaces, the broadcast will go to all of those (sub)networks. -What do you do, though, if you need to get past a router? My advice -is to write a server that will run on hosts on both sides of your router. -When a server on one side of the router receives a broadcast, it would -send a directed datagram to it's counterpart on the other side of the router. -The counterpart would then re-broadcast the original datagram on that sub-net. -Cheap, simple and effective.</BLOCKQUOTE> -One final word of warning: -<BLOCKQUOTE>When creating your broadcast datagrams you may see something -like this: <I>ACE_SOCK_Dgram_Bcast::mk_broadcast: Broadcast is not -enable for this interface.: Unknown error</I>. There are some interfaces -(ppp, slip) that don't support broadcast datagrams. That's what you're -seeing here.</BLOCKQUOTE> -Ok, one more warning: -<blockquote>If you happen to have multiple servers running on your -network when you invoke this client, the response could come from any -one of them. -</blockquote> - -<P><HR WIDTH="100%"> -<CENTER>[<A HREF="../online-tutorials.html">Tutorial Index</A>] [<A HREF="page05.html">Continue This Tutorial</A>]</CENTER> |