Re: inter-process communication

From:

"AliR $VC++ MVP$" <AliR@online.nospam>

Newsgroups:

microsoft.public.vc.mfc

Date:

Mon, 8 Oct 2007 09:40:31 -0500

Message-ID:

<vnrOi.4687$oA2.3381@nlpi068.nbdc.sbc.com>

I would go with the callback. It is more reliable, and easier. SendMessage
with HWND_BROADCAST will only be sent to the top level window of each
application, and if the code that handles that event is not in the main
window, then you will have to do alot of redirecting.

Callback function will get all the information to whoever is asking for it.

AliR.

"Steph" <steph@newsgroups.nospam> wrote in message
news:3184ADE7-00B3-4266-98F7-5E94BAAAA26D@microsoft.com...

Hi,

We have a dll which makes/monitors system changes. At the moment, all
interested applications regularly poll the dll to check for changes, but
this
is not ideal, and we would prefer the dll to inform relevant applications
of
the event.

Are windows messages the best way to do this? If so, I understand that I
would need to use a registered windows message with a unique string. But
what
is the best way to send the message? SendMessageTimeout or
SendNotifyMessage
or even PostMessage?

It is unlikely the dll will need to receive information back from the
apps,
but it may need to pass additional information with the message. Is it
possible to do this, or would it be best to have the applications, use a
dll
function to read this info on receipt of the message (which would
introduce
the possibility of incorrect data if the state changes before this is
read?)

If windows messages are not the way to go, what is? Apps registering a
callback?

I am using windows Vista.

Thank you and regards