return value of WM

return value of WM_QUIT

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

Bonj - 15 Nov 2004 14:13 GMT

Hi
I am having an issue with a window I am creating - in its wndproc, if I call
PostMessage(hWnd, WM_QUIT, 0, 0) in response to WM_DESTROY, then GetMessage
returns a non-zero value and the loop carries on. But if I post quit message
in response to WM_CLOSE - it works fine!
I thought you were supposed to post WM_QUIT in response to WM_DESTROY though?

Reply to this Message

Alexander Grigoriev - 15 Nov 2004 15:01 GMT

You're not supposed to use PostMessage for WM_QUIT. Use PostQuitMessage
instead.

> Hi
> I am having an issue with a window I am creating - in its wndproc, if I
[quoted text clipped - 6 lines]
> I thought you were supposed to post WM_QUIT in response to WM_DESTROY
> though?

Reply to this Message

Bonj - 15 Nov 2004 15:09 GMT

Please read my other posts on the same issue for the reasons as to why I don't.

> You're not supposed to use PostMessage for WM_QUIT. Use PostQuitMessage
> instead.
[quoted text clipped - 9 lines]
> > I thought you were supposed to post WM_QUIT in response to WM_DESTROY
> > though?

Reply to this Message

Alexander Grigoriev - 16 Nov 2004 04:36 GMT

Anyway, during WM_DESTROY, HWND may be already invalid. Actually, the reason
for failure is that when you do GetMessage, the window will already be
destroyed and the message will be discarded as invalid.

You're better with PostThreadMessage(GetCurrentThreadId(), WM_QUIT).

> Please read my other posts on the same issue for the reasons as to why I
> don't.
[quoted text clipped - 12 lines]
>> > I thought you were supposed to post WM_QUIT in response to WM_DESTROY
>> > though?

Reply to this Message

Bonj - 18 Nov 2004 14:12 GMT

I eventually found the cause of this ish.
It was that I was calling
while(GeMessage(&msg, hWnd, 0, 0) != 0)
instead of
while(GetMessage(&msg, NULL, 0, 0) != 0)

and due to this, PostQuitMessage doesn't actually post a message to the
hWnd, just to the thread. So the WM_QUIT message was being issued correctly,
it just wasn't getting through!

> Anyway, during WM_DESTROY, HWND may be already invalid. Actually, the
> reason for failure is that when you do GetMessage, the window will already
[quoted text clipped - 19 lines]
>>> > I thought you were supposed to post WM_QUIT in response to WM_DESTROY
>>> > though?

Reply to this Message

Rate this thread:

return value of WM_QUIT

Free Magazines