Subclassing

NTDEV
1

Hi,
I was gathering information on subclassing and I went through chat windows
of MSN 6.0 Version. When I look at this window in SPY++, I found that SPY
mention its window procedure as sunclassed.

My question is how SPY finds out that a particular window procedure is
subclassed or not. Is there any API or it is just a huristic technique.

Thanks in advance
Ashish

2

This newsgroup is primarily for kernel-mode development, but I’ll take a
shot. Assuming the window has been instance subclassed instead of
globally subclassed, Spy++ could be comparing the value of the windows
procedure attribute in the window’s class against the attribute value in
the window; if they differ, the window instance has been subclassed.

Ashish wrote:

Hi,
I was gathering information on subclassing and I went through chat windows
of MSN 6.0 Version. When I look at this window in SPY++, I found that SPY
mention its window procedure as sunclassed.

My question is how SPY finds out that a particular window procedure is
subclassed or not. Is there any API or it is just a huristic technique.

Thanks in advance
Ashish

–
Nick Ryan (MVP for DDK)

3

For ‘well known controls’, it could even be comparing to well-known
winprocs.

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Nick Ryan
Sent: Tuesday, October 07, 2003 1:08 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] Re: Subclassing

This newsgroup is primarily for kernel-mode development, but I’ll take a
shot. Assuming the window has been instance subclassed instead of
globally subclassed, Spy++ could be comparing the value of the windows
procedure attribute in the window’s class against the attribute value in
the window; if they differ, the window instance has been subclassed.

Ashish wrote:

Hi,
I was gathering information on subclassing and I went through chat
windows of MSN 6.0 Version. When I look at this window in SPY++, I
found that SPY mention its window procedure as sunclassed.

My question is how SPY finds out that a particular window procedure is
subclassed or not. Is there any API or it is just a huristic
technique.

Thanks in advance
Ashish

–
Nick Ryan (MVP for DDK)

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

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