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"4N" <xxxx@yyyy.zzz> wrote in message
news:468d2ea0@newsgroups.borland.com...

> I've integrated gdi+ in a project, but I have a problem with the
> header files: the compiler can't choose the correct constructor
> for the Gdiplus::Graphics class (to be precise I use the following
> command "Gdiplus::Graphics graphics(hdc);" ).

I use that same statement in my GDI+ code and it works fine for me.

> I can solve it declaring STRICT as parameter in the global
definitions but
> this leads to a load of casts in my other functions.

Then those calls were probably wrong to begin with.  Can you provide
an example of what is not working anymore?


Gambit

oops, maybe I should have used the "graphics" group, sorry.

> I use that same statement in my GDI+ code and it works fine for me.

How? If I don't define STRICT the code stops in the last line of the 
following code (inside the file GDIPLUSGRAPHICS.H):

class Graphics : public GdiplusBase
{
public:
    friend class Region;
    friend class GraphicsPath;
    friend class Image;
    friend class Bitmap;
    friend class Metafile;
    friend class Font;
    friend class FontFamily;
    friend class FontCollection;
    friend class CachedBitmap;

    static Graphics* FromHDC(IN HDC hdc)
    {
        return new Graphics(hdc);

and I get the errors:

[C++ Error] GdiplusGraphics.h(34): E2015 Ambiguity between 
'Gdiplus::Graphics::Graphics(void *)' and 'Gdiplus::Graphics::Graphics(void 
*,int)'
[C++ Error] OpenImages.cpp(294): E2015 Ambiguity between 
'Gdiplus::Graphics::Graphics(void *)' and 'Gdiplus::Graphics::Graphics(void 
*,int)'


If I define STRICT there are functions that need cast, eg. an error I get 
is:

const HANDLE handle=...;
 GetWindowLong(handle, GWL_STYLE);

  [C++ Error] Unit_Main.cpp(3297): E2034 Cannot convert 'void * const' to 
'HWND__ *'
  [C++ Error] Unit_Main.cpp(3297): E2342 Type mismatch in parameter 'hWnd' 
(wanted 'HWND__ *', got 'void *')

"4N" <xxxx@yyyy.zzz> wrote in message
news:468d3c18@newsgroups.borland.com...

> How?

I don't use STRICT in my code and it works fine.  I don't do anything
special for it.

> If I don't define STRICT the code stops in the last line
> of the following code (inside the file GDIPLUSGRAPHICS.H):

Then the compiler is wrong.  There is no ambiquity in that code.  The
Graphics class has only two constructors which accept an HDC as a
parameter.  The first constructor accepts only an HDC by itself,
whereas the second constructor accepts an additional HANDLE parameter.
That parameter does not have a default value defined, however, so
there is no way that passing an HDC by itself to a Graphics
constructor like FromHDC(HDC) does can be ambiquious with the second
constructor.  It doesn't matter if STRICT is defined or not.  The
number of parameters dictates which constructor to call before the
parameter types are then validated.

> If I define STRICT there are functions that need cast, eg. an
> error I get is:
>
> const HANDLE handle=...;
>  GetWindowLong(handle, GWL_STYLE);
>
>   [C++ Error] Unit_Main.cpp(3297): E2034 Cannot convert 'void *
const'
> to 'HWND__ *'

The error is correct in this case.  Your code is simply wrong to begin
with.  GetWindowLong() expects an HWND, not a HANDLE.  The two are not
the same thing, especially more so when STRICT is defined.  This is
exactly the type of thing that STRICT was designed for - it forces you
to use proper coding so that you can catch such errors.  When STRICT
is not defined, HANDLE and HWND are both void* and thus are
interchangable in code, but that is not necessarily the right thing to
do logically.


Gambit

> Then the compiler is wrong.  There is no ambiquity in that code.  The
> Graphics class has only two constructors which accept an HDC as a
> parameter.  The first constructor accepts only an HDC by itself,
> whereas the second constructor accepts an additional HANDLE parameter.
> That parameter does not have a default value defined, however, so
> there is no way that passing an HDC by itself to a Graphics
> constructor like FromHDC(HDC) does can be ambiquious with the second
> constructor.  It doesn't matter if STRICT is defined or not.  The
> number of parameters dictates which constructor to call before the
> parameter types are then validated.

the compiler is wrong obviously, but the point is: what can I do to make it 
work properly ?
Have I to assume there's no solution (for you at least) since you didn't 
point me any?

Anyway thanks again for the time you spent replying to me. 

4N wrote:
> oops, maybe I should have used the "graphics" group, sorry.
> 
> 
> If I define STRICT there are functions that need cast, eg. an error I get 
> is:
> 
> const HANDLE handle=...;
>  GetWindowLong(handle, GWL_STYLE);

As Remy told you GetWindowLong expects HWND and not const HANDLE (const 
void*).

Dirty hack would be something like this:

GetWindowLong(reinterpret_cast<HWND>(const_cast<HANDLE>(handle)),GWL_STYLE);

I just do not understand why are you using HANDLE in the first place 
instead of HWND.

Remy Lebeau (TeamB) wrote:

>Then the compiler is wrong.  There is no ambiquity in that code.  The
>Graphics class has only two constructors which accept an HDC as a
>parameter.  The first constructor accepts only an HDC by itself,
>whereas the second constructor accepts an additional HANDLE parameter.
>That parameter does not have a default value defined, however, so
>there is no way that passing an HDC by itself to a Graphics
>constructor like FromHDC(HDC) does can be ambiquious with the second
>constructor.  It doesn't matter if STRICT is defined or not.  The
>number of parameters dictates which constructor to call before the
>parameter types are then validated.

From my C perspective, those constructors are forward references (FromHDC(HDC) occurs
before the HDC constructor is described).
It seems to me that the compiler might make assumptions about a default constructor, but
be unable to reconcile 2 different constructors that it doesn't know about.

Darko Miletic <kiklop@fibertel.com.ar> wrote:

>> const HANDLE handle=...;
>>  GetWindowLong(handle, GWL_STYLE);


>GetWindowLong(reinterpret_cast<HWND>(const_cast<HANDLE>(handle)),GWL_STYLE);

Why the const_cast<>? It should be totally irrelevant, since it's a top
level const in this case, and GetWindowLong receives its first parameter
by value, not by reference.

Alan Bellingham
-- 
Team Browns
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> I just do not understand why are you using HANDLE in the first place 
> instead of HWND.

because the value I assign to the variable is a HANDLE, anyway the point 
isn't that, that was just an example. 

"4N" <xxxx@yyyy.zzz> wrote in message
news:468d6d7e$1@newsgroups.borland.com...

> because the value I assign to the variable is a HANDLE

Then it probably isn't a real HWND to begin with.

> anyway the point isn't that, that was just an example.

Then it was a bad example.  You really do need to make sure that you
are always using proper data types in all operations.


Gambit

> Then it was a bad example.  You really do need to make sure that you
> are always using proper data types in all operations.

yeah, ok, my mistake.
Anyway I corrected all the calls and now I can use the gdi+ using STRICT as 
global define, but I wonder why it happens.
It's a known issue anyway as I could read here:

http://www.leunen.com/cbuilder/gdiplus.html