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diff --git a/docs/tutorials/010/page05.html b/docs/tutorials/010/page05.html deleted file mode 100644 index 1e9ddef1cc6..00000000000 --- a/docs/tutorials/010/page05.html +++ /dev/null @@ -1,171 +0,0 @@ -<!-- $Id$ --> -<HTML> -<HEAD> - <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> - <META NAME="Author" CONTENT="James CE Johnson"> - <TITLE>ACE Tutorial 010</TITLE> -</HEAD> -<BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#000FFF" VLINK="#FF0F0F"> - -<CENTER><B><FONT SIZE=+2>ACE Tutorial 010</FONT></B></CENTER> - -<CENTER><B><FONT SIZE=+2>Passing chunks of data through an ACE_Message_Queue</FONT></B></CENTER> - - -<P> -<HR WIDTH="100%"> - -Our <A HREF="task.cpp">Task</A> object definition. -<P> -Something to look at here is the ACE_Barrier usage. In the -constructor, we tell the barrier how many threads we're using. Then, -in the svc() method, we use the barrier's wait() method. You can -think of the barrier as a semaphore initialized to the thread count. - Each time wait() -is invoked, the semaphore is decremented and the thread is blocked. - When the count equals zero, all threads are unblocked and allowed to -continue. -<P> -<font size=-1>Note: This isn't the way ACE_Barrier really works, it's -just an analogy</font> - -<HR WIDTH="100%"> -<PRE> -<font color=red>// $Id$</font> - -<font color=blue>#include</font> "<font color=green>task.h</font>" -<font color=blue>#include</font> "<font color=green>block.h</font>" - -<font color=red>/* Set our housekeeping pointer to NULL and tell the user we exist. */</font> -<font color=#008888>Task::Task</font> (size_t n_threads) - : barrier_ (n_threads), - n_threads_ (n_threads) -{ - ACE_DEBUG ((LM_DEBUG, - "<font color=green>(%P|%t) Task ctor 0x%x\n</font>", - (void *) this)); -} - -<font color=red>/* Take care of cleanup & tell the user we're going away. */</font> -<font color=#008888>Task::~Task</font> (void) -{ - ACE_DEBUG ((LM_DEBUG, - "<font color=green>(%P|%t) Task dtor 0x%x\n</font>", - (void *) this)); - - <font color=red>/* Get our shutdown notification out of the queue and release it. */</font> - ACE_Message_Block *message; - - <font color=red>/* Like the getq() in svc() below, this will block until a message - arrives. By blocking, we know that the destruction will be paused - until the last thread is done with the message block. */</font> - this->getq (message); - message->release (); -} - -<font color=red>/* Open the object to do work. Next, we activate the Task into the - number of requested threads. */</font> -int -<font color=#008888>Task::open</font> (void *unused) -{ - ACE_UNUSED_ARG (unused); - - return this->activate (THR_NEW_LWP, - n_threads_); -} - -<font color=red>/* Tell the user we're closing and invoke the baseclass' close() to - take care of things. */</font> -int -<font color=#008888>Task::close</font> (u_long flags) -{ - ACE_DEBUG ((LM_DEBUG, - "<font color=green>(%P|%t) Task close 0x%x\n</font>", - (void *) this)); - return <font color=#008888>inherited::close</font> (flags); -} - -<font color=red>/* Our svc() method waits for work on the queue and then processes - that work. */</font> -int -<font color=#008888>Task::svc</font> (void) -{ - <font color=red>/* This will cause all of the threads to wait on this line until all - have invoked this method. The net result is that no thread in the - Task will get a shot at the queue until all of the threads are - active. There's no real need to do this but it's an easy intro - into the use of ACE_Barrier. */</font> - this->barrier_.wait (); - - ACE_DEBUG ((LM_DEBUG, - "<font color=green>(%P|%t) Task 0x%x starts in thread %d\n</font>", - (void *) this, - <font color=#008888>ACE_Thread::self</font> ())); - - <font color=red>/* Remember that get() needs a reference to a pointer. To save - stack thrashing we'll go ahead and create a pointer outside of the - almost- infinite loop. */</font> - ACE_Message_Block *message; - - for (;;) - { - <font color=red>/* Get a message from the queue. Note that getq() will block - until a message shows up. That makes us very - processor-friendly. */</font> - if (this->getq (message) == -1) - ACE_ERROR_RETURN ((LM_ERROR, - "<font color=green>%p\n</font>", - "<font color=green>getq</font>"), - -1); - <font color=red>/* If we got the shutdown request, we need to go away. */</font> - if (message->msg_type () == <font color=#008888>ACE_Message_Block::MB_HANGUP</font>) - { - <font color=red>/* Forward the request to any peer threads. */</font> - this->putq (message); - - <font color=red>/* Leave the infinite loop so that the thread exits. */</font> - break; - } - - <font color=red>/* The message queue stores char* data. We use rd_ptr() to get - to the beginning of the data. */</font> - const char *cp = message->rd_ptr (); - - <font color=red>/* Move the rd_ptr() past the data we read. This isn't real - useful here since we won't be reading any more from the block - but it's a good habit to get into. */</font> - message->rd_ptr (<font color=#008888>ACE_OS::strlen</font> (cp)); - - <font color=red>/* Display the block's address and data to the user. */</font> - ACE_DEBUG ((LM_DEBUG, - "<font color=green>(%P|%t) Block 0x%x contains (%s)\n</font>", - (void *) message, - cp)); - - <font color=red>/* Pretend that it takes a while to process the data. */</font> - <font color=#008888>ACE_OS::sleep</font> (ACE_Time_Value (0, 5000)); - - <font color=red>/* Release the message block. Notice that we never delete a - message block. Blocks are reference counted & the release() - method will take care of the delete when there are no more - references to the data. */</font> - message->release (); - } - - return 0; -} -</PRE> -<HR WIDTH="100%"> -<P> -This is all pretty straight-forward too. One gottcha we avoided was a memory leak -due to our shutdown message. Notice that svc() enqueues that block without bothering -to see if there are any more threads to dequeue it. Thats why our dtor can call getq() -without worrying about blocking infinitely: it knows the message block will be there. -<P> -Also notice that we haven't used <i>THR_DETACHED</i> in this - tutorial. Why? Because in <i>message_queue.cpp</i> we call - <i>wait()</i> to wait for all of the task's threads to exit. - That prevents the leak that we normally avoid by using <i>THR_DETACHED</i>. -<P><HR WIDTH="100%"> -<CENTER>[<A HREF="../online-tutorials.html">Tutorial Index</A>] [<A HREF="page06.html">Continue This Tutorial</A>]</CENTER> - |