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Hi,

Is this right?

1)if I register a WNDCLASS in witch set cbWndExtra to a value greater than
0, this means that every time I create a window of that class there will be
an extra amount of memory alocated.

2)I can put something into that extra memory.

If the two statements are correct:

How can I write and read from that extra memory.

Thank you
Karel Bruneel

On Sat, 30 Aug 2003 19:36:19 GMT, "Karel Bruneel" <> wrote:

>Hi,
>
>Is this right?
>
>1)if I register a WNDCLASS in witch set cbWndExtra to a value greater than
>0, this means that every time I create a window of that class there will be
>an extra amount of memory alocated.

Not necessarily, but there's an extra amount of memory _available_ for
your use.



>2)I can put something into that extra memory.

Yes.

But since every Win32 window has room for a user-defined pointer you
generally don't need to specify more storage.

It's a relic from 16-bit Windows.


(Note that there are many other ways to associate data with a window,
including (1) SetProp/GetProp, (2) dynamically generated window proc
stub, and (3) static association table.)


>If the two statements are correct:
>
>How can I write and read from that extra memory.

GetWindowLong, SetWindowLong.

On Sat, 30 Aug 2003 19:54:03 GMT, (Alf P. Steinbach) wrote:
>

I'm sorry, I didn't notice this was crossposted to [comp.lang.c++].

Karel: DON'T DO THAT.

Or else...

I thank all of you.


"Karel Bruneel" <> schreef in bericht
news:T074b.9675$...
> Hi,
>
> Is this right?
>
> 1)if I register a WNDCLASS in witch set cbWndExtra to a value greater than
> 0, this means that every time I create a window of that class there will
be
> an extra amount of memory alocated.
>
> 2)I can put something into that extra memory.
>
> If the two statements are correct:
>
> How can I write and read from that extra memory.
>
> Thank you
> Karel Bruneel
>
>
>