🚀 go-pugleaf

A structure definition is a type.  You can then declare or 
allocate one or more instances of a type.  While for 
efficiency only one set of physical instructions is 
generated for a member function of a structure, the manner 
in which the function is called includes specifying which 
instance of the type those instructions are to work with. 

You specified a member function of a structure to Windows 
as a callback function.  Windows is not party to the 
internal configuration of your program and has no 
facilities to call a non static member function in the 
context of whatever instance of that structure you 
intended to be used. 

Only static member functions and normal functions that 
are not members of a class or structure can be specified
as callback functions. 

.  Ed 

>FireHead wrote:
>
>...
>As you can see that I have function called LRESULT 
>CALLBACK Events(....) 
>which globally located.
>
>I have function called InitInstance which is part of 
>Main_Window structure.
>
>Where I declare WNDCLASSEX wnd
>and then I declare the expression
>as << 
>    wnd.lpfnWndProc = & sig.Events; 
> >> I get a error type casting in 
>the following:
>
>Cannot convert 
>'long (_stdcall *(_closure)(HWND__*,unsigned 
>  int,UINT,long))(HWND__* hwnd,unsigned int,UINT,long)'
>to 
>'long (_stdcall *)(HWND__* hwnd,unsigned int,UINT,long)' 
>in function 
>struct MainWindow::InitInstance(const char*)
>
>Can someone tell me how do I fix this problem.