Defining a custom *constructor* (not initializer!)

[Mehrdad]

On Friday, 11 May 2012 at 14:17:04 UTC, Steven Schveighoffer 
wrote:
> Yeah, but given that the subclass is calling the base 
> constructor, and the base constructor does not return until 
> WM_CREATE is received, can't the subclass constructor pretend 
> it received the message?
>
> -Steve

"pretend"?

No, because the window handle doesn't even EXIST until WM_CREATE 
passes it to the window instance! (Sorry I guess I didn't mention 
that, but it was kind of implicit in the fact that messages are 
passed *before* CreateWindow() returns.)

Yes, CreateWindow() also returns a copy of the handle, but stuff 
happens *before* the handle is returned, and in order for the 
class to properly handle it, the handle is passed along with 
WM_CREATE (and, in fact, with another message called WM_NCCREATE, 
but we can ignore that for now).
The subclass has NO access to the window handle whatsoever before 
the message comes, so no, it can't "pretend" to have received the 
handle because that wouldn't be of any use.