• Thorn (11/11) Aug 15 2005 Hello everybody! Help me, please.
• Stewart Gordon (22/35) Aug 16 2005 "Everybody" now uses digitalmars.D and its descendant 'groups. This one...

Thorn <Thorn_member pathlink.com> writes:

Hello everybody! Help me, please.
I try to create Window class (under Win32). As we know we need register window
class with message processing function. We need only simple 32-bit address
(pointer) of that function. I tried to get one in constructor:

this() {
wc.WinProc = &this.MyWinProc;
..

BUT compiler complains that it can't convert from delegate(!!!) to pointer. How
I can obtain it?
Documentation says that even delegate has two parts: object AND address! I want
to take last one :) Thank you!

Stewart Gordon <smjg_1998 yahoo.com> writes:

Thorn wrote:
 Hello everybody! Help me, please.

"Everybody" now uses digitalmars.D and its descendant 'groups.  This one 
is deprecated.  Followup set.

 I try to create Window class (under Win32). As we know we need register window
 class with message processing function. We need only simple 32-bit address
 (pointer) of that function. I tried to get one in constructor:
 
 this() {
 wc.WinProc = &this.MyWinProc;
 ..
 
 BUT compiler complains that it can't convert from delegate(!!!) to pointer. How
 I can obtain it?

You can't.  A member function doesn't have an address individual to the 
object it's called on.

 Documentation says that even delegate has two parts: object AND address! I want
 to take last one :) Thank you!

Exactly.  It's physically impossible to call the function given only one 
of these bits of information.

Internally, something like this:

     class Qwert {
         int yuiop(uint asdfg) { ... }
     }

looks something like this

     int Qwert.yuiop(Qwert this, uint asdfg) { ... }

not, as you seem to think, as a separate copy of the function for each 
object.

If there is only one Window object, then make the member static. 
Otherwise, write a static wrapper function that looks up the HWND.  As 
SDWF, and probably other GUI libraries, do internally.

Stewart.

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