Re: RegisterWindowMessage, HWND_BROADCAST between exe and dll issue

From:

"Igor Tandetnik" <itandetnik@mvps.org>

Newsgroups:

microsoft.public.vc.mfc,microsoft.public.vc.language

Date:

Fri, 27 Apr 2007 15:19:47 -0400

Message-ID:

<ehi8FEQiHHA.392@TK2MSFTNGP06.phx.gbl>

neinna@gmail.com wrote:

i have an exe, let's call it exe1, that is ours, that runs as some
user, "Administrator" in this particular case, on a given machine,
that does following:

UINT uiStringA = RegisterWindowMessage("StringA")

and then has

ON_REGISTERED_MESSAGE(uiStringA, stringAHandler);

then i have a vendor's exe, that runs as a service under "System" user
and that loads 1 standard c dll, which in turn loads 2nd dll, let's
call it dll2, which is also ours and mfc, that also does:

UINT uiStringA = RegisterWindowMessage("StringA")

and then
PostMessage (HWND_BROADCAST, uiStringA...)

Services run in a separate window station, and have their own desktop.
Window messages can only be sent between windows on the same desktop.
You won't be able to use window messages for communication between a
regular process and a service. Choose a different IPC mechanism.
--
With best wishes,
Igor Tandetnik

With sufficient thrust, pigs fly just fine. However, this is not
necessarily a good idea. It is hard to be sure where they are going to
land, and it could be dangerous sitting under them as they fly
overhead. -- RFC 1925