Re: how to tell if hwnd is valid
OK, I see what you are saying. I know I'm not exactly using your wrapper
the way it was intended:
I have a canThread and appThread that extends CWinThread and canWnd and
appWnd that extends CWnd.
a canThread is created imediately at start up, which then creates a canWnd
which is responsible to responding to CANLIB's incoming packet
notifications.
When a client connects to the backend, it then creates an appThread which
then creates a appWnd. AppWnd receives messages from canWnd, applies
filters to the packets, and then sends them off to the client via
WM_COPYDATA.
I use your MsgWrapper just for packet communication. in canWnd I use
MsgWrapper::Post to send packets to appWnd. in canThread::onIdle() I then
MsgWrapper::Forward() those messages.
By using this method, I noticed that I have been dropping packets, and I
traced it the MsgWrapper::Forward() function where PostMessage was failing
and the message got deleted.
does each thread or window have its own message queue?
"Joseph M. Newcomer" <newcomer@flounder.com> wrote in message
news:78e1945i2vevabj41942vfp7jtddsf6eus@4ax.com...
See below...
On Wed, 30 Jul 2008 10:45:13 -0700, "Nick Schultz" <nick.schultz@flir.com>
wrote:
"Joseph M. Newcomer" <newcomer@flounder.com> wrote in message
news:6e8194ppbtindjgboinq4lngvb754tn7ne@4ax.com...
See below...
On Wed, 30 Jul 2008 09:25:16 -0700, "Nick Schultz"
<nick.schultz@flir.com>
wrote:
Well I am using Mr. Newcomer's Completion I/O MsgWrapper to send
messages
between threads, however in large data bursts, the message pump gets
saturated and messages don't post.
****
That's simply not true. The whole point of the IOCP technique is so
that
messages do NOT
get lost!
*****
What happens when PostMessage returns false?
BOOL PostMessage(
HWND hWnd,
UINT Msg,
WPARAM wParam,
LPARAM lParam
);
Return Value
If the function succeeds, the return value is nonzero.
If the function fails, the return value is zero.
your code deletes the message regardless of the return value
****
This is based on the premise that there is no message queue saturation,
and since I am
only dequeing 10-20 messages at a time, I cannot possibly get message
queue saturation.
Note that I know the message queue is empty because I'm in the OnIdle
handler.
****
BOOL MsgWrapper::Forward()
{
BOOL result = wnd->PostMessage(msg, wParam, lParam));
delete this;
return result;
}
so if the message queue is filled, messages are dropped.
****
But, since it is obvious that it cannot possibly be filled (remember, we
are in the OnIdle
handler, which means that the message queue is empty!) there is no need to
check! Since I
do not do PostMessage except via the IOCP queue, there is no possibility
the queue could
be saturated!
joe
****
I see what you are saying about not closing the window until it has
processed all of its messages and will look into that.
Joseph M. Newcomer [MVP]
email: newcomer@flounder.com
Web: http://www.flounder.com
MVP Tips: http://www.flounder.com/mvp_tips.htm