DialogBox BUG

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3 total messages Started by ScOe Wed, 26 Mar 2003 18:20

#17395

Author: ScOe
Date: Wed, 26 Mar 2003 18:20

21 lines
1874 bytes

I've encounter one BUG with c++ builder or something ... and i dont know how
to fix it ...
Problem is following ...
i'm calling DialogBox function and for MyDialogProc
    fResult = DialogBox (hInstance, TEXT ("AboutBox"), 0, MyDialogProc) ;
error code that i'm receiving is:
    E2034 Cannot convert 'int (__stdcall *)(void *,unsigned int,unsigned
int,long)' to 'int (__stdcall*)()'
    E2342 Type mismatch in parameter 'lpDialogFunc' (wanted 'int (__stdcall
*)()', got 'int (__stdcall *)(void *,unsigned int,unsigned     int,long)')

this is declaration of lpDialogFunc function:
BOOL CALLBACK MyDialogProc(HWND hWnd, UINT nMessage, WPARAM wParam, LPARAM
lParam)

I dont know how did he expect to get 'int (__stdcall *)()' when in winhelp
is wroten that 'lpDialogFunc' expect 'int (__stdcall *)(void *,unsigned
int,unsigned     int,long)' callback function.
I saw in Charles Petzold example that is using same parametered procedure.
Tried to compile it but i receive same kind of error ... so problem must be
in C++ Builder.

Re: DialogBox BUG

#17397

Author: Remy Lebeau (TeamB)
Date: Wed, 26 Mar 2003 18:50

40 lines
2238 bytes

"ScOe" <sven.savic@zg.hinet.hr> wrote in message
news:3e81ef72@newsgroups.borland.com...
> I've encounter one BUG with c++ builder or something ...
> and i dont know how to fix it ...

That's not a bug in Builder, but in your understanding in how your own code
should work.

> i'm calling DialogBox function and for MyDialogProc
>     fResult = DialogBox (hInstance, TEXT ("AboutBox"), 0, MyDialogProc) ;
> error code that i'm receiving is:
>     E2034 Cannot convert 'int (__stdcall *)(void *,unsigned int,unsigned
> int,long)' to 'int (__stdcall*)()'

Your dialog procedure doesn't match the function signature DialogBox() is
expecting.  You need to cast your function pointe when you pass it in:

    fResult = DialogBox (hInstance, TEXT ("AboutBox"), 0,
(DLGPROC)MyDialogProc) ;

> I dont know how did he expect to get 'int (__stdcall *)()' when in winhelp
> is wroten that 'lpDialogFunc' expect 'int (__stdcall *)(void *,unsigned
> int,unsigned     int,long)' callback function.

That is because DLGPROC has a different declaration depending on whether
STRICT is defined or not, which is not defined by default:

typedef int (FAR WINAPI *FARPROC)();

...

#ifdef STRICT
typedef INT_PTR (CALLBACK* DLGPROC)(HWND, UINT, WPARAM, LPARAM);
#else
typedef FARPROC DLGPROC;
#endif


Gambit

Re: DialogBox BUG

#17388

Author: ScOe
Date: Wed, 26 Mar 2003 19:37

15 lines
1306 bytes

"Remy Lebeau (TeamB)" <gambit47@yahoo.com> wrote in message
news:3e81f425$1@newsgroups.borland.com...
>
> "ScOe" <sven.savic@zg.hinet.hr> wrote in message
> news:3e81ef72@newsgroups.borland.com...

> That's not a bug in Builder, but in your understanding in how your own
code
> should work.

Thanx for reply.
> Gambit
>
>

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