Posted on 2002-03-21
Last Modified: 2008-02-01
Hellow experts...

In a cpp file almost the first line is this prototype.


Of course that function is defined at the bottom of the file.

The problem is this one.

In the InitDialog message (I am trying to subclass an item in the dialog) I am trying to:

WNDPROC OldAdd = SetWindowLong (hItemWnd, GWL_WNDPROC, (LONG)ShowPointWndProc);

This will never be compiled because the error is this.

DialogProcs.cpp(34) : error C2440: '=' : cannot convert from 'long' to 'long (__stdcall *)(struct HWND__ *,unsigned int,unsigned int,long)'

I tried:

WNDPROC OldAdd = SetWindowLong (hItemWnd, GWL_WNDPROC, (LONG)&ShowPointWndProc);

WNDPROC OldAdd = SetWindowLong (hItemWnd, GWL_WNDPROC, (WNDPROC)&ShowPointWndProc);

But nothing works...

Please help me.

Thank you very much.

Question by:Marsc
LVL 86

Accepted Solution

jkr earned 50 total points
ID: 6885477
Make it read

WNDPROC OldAdd = (WNDPROC) SetWindowLong (hItemWnd, GWL_WNDPROC, (LONG)ShowPointWndProc);

'SetWindowLong()' returns a 'long', you'll have to typecast when storing it as a 'WNDPROC'...

Author Comment

ID: 6886292
Problem solved :-)
Thank you very much...

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