ACE Tutorial 015
Building a protocol stream

We'll take a look first at the client application. As usual, our goal is to keep the main() application as simple as possible and delegate the tricky stuff to another object.

// $Id$

/* The Client object will implement the nasty details of connecting to
   communicating with the server
#include "Client_i.h"

int main(int argc, char *argv[])
        // How many messages will we send?
    int mcount = argc > 1 ? ACE_OS::atoi(argv[1]) : 3;

        // Construct a Client with our desired endpoint.

        // Attempt to open the connection to the server.
    if( == -1 )
        ACE_ERROR_RETURN ((LM_ERROR, "%p\n", "Client::open()"), -1);

        // Send a few messages to the server and get some responses...
    for( int i = 0 ; i < mcount ; ++i )
            // Since we'll be using a Protocol Stream (even though we
            // don't know that at this level) we require the use of
            // ACE_Message_Block objects to send/receive data.
        ACE_Message_Block * message = new ACE_Message_Block( 128 );

            // Construct a silly message to send to the server.
            // Notice that we're careful to add one to the strlen() so
            // that we also send the end-of-string NULL character.
        ACE_OS::sprintf (message->wr_ptr (), "This is message %d.", i);
        message->wr_ptr (strlen (message->rd_ptr ())+1);

            // client will take ownership of the message block so that
            // we don't have to remember to release().  We *do* have
            // to remember not to use it after put() since it may be
            // released almost immediately.
        client.put( message );

        ACE_Message_Block * response;

            // get() takes an ACE_Message_Block pointer reference.  We then
            // assume ownership of it and must release() when we're done.
        if( client.get( response ) == -1 )
            ACE_DEBUG ((LM_INFO, "(%P|%t) Failed to get response from server\n" ));

        ACE_DEBUG ((LM_INFO, "(%P|%t) The server's response:  (%s)\n",

            // Now that we're through with the response we have to
            // release() it to avoid memory leaks.

    ACE_DEBUG ((LM_INFO, "(%P|%t) Shutting down the stream\n" ));

        // Before we exit, it's a good idea to properly close() the connection.
    if( client.close() == -1 )
        ACE_ERROR_RETURN ((LM_ERROR, "%p\n", "Client::close()"), -1);


[Tutorial Index] [Continue This Tutorial]