Re: Translating a VB dll header to Ada

[vienapl@hotmail.com]

That is the correct answer, it works!

Thank you a lot Philippe and Dmitry.

However, now I'm having trouble with the

  procedure CKHSendString (helper : System.Address; data : in
Interfaces.C.Char_Array);
  pragma Import (C, CKHSendString, External_Name => "CKHSendString");

function. It doesn't raise an exception, but it does not seem to do
anything at all. It works fine when used from the VB6 or C++ samples.

Thank you so much, again.

On Apr 14, 5:30 pm, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
wrote:
> On 14 Apr 2007 05:16:33 -0700, vien...@hotmail.com wrote:
>
> > Yes, it does work with only those two functions.
>
> > I don't know which parameter could be wrong on the CTHSetText
> > function. If I change a Char_Array for a WChar_Array I get a raised
> > PROGRAM_ERROR : EXCEPTION_ACCESS_VIOLATION instead, but the debugger
> > prompts the same message.
>
> OK, C++ code you have referred to, looks quite ..., so let me suggest a bit
> offending thing. What if they copy pointers to strings?
>
> So what happens if you allocate the string passed to CTHSetText statically:
>
>    Object_Text : Interfaces.C.Char_Array :=
>        Interfaces.C.To_C ("Object");
> begin
>    ...
>    CTHSetText (TextHelperID, Object_Text);
>        -- CTHSetText remembers a pointer to Object_Text, which has to
>        -- exist as long as the library may dereference it
>    ...
>
> Another suggestion. If CTHSetText actually takes a pointer to a dynamically
> allocated string which will be freed later somewhere inside the library.
> Then CTHSetText should be declared like this:
>
>    procedure CTHSetText
>      (Helper : System.Address; Name_Ptr : Interfaces.C.Strings.chars_ptr);
>    pragma Import (C, CTHSetText, ...);
>
> and used as:
>
>    CTHSetText (TextHelperID, Interfaces.C.Strings.New_String ("Object"));
>        -- CTHSetText takes care of the memory allocated
>
> --
> Regards,
> Dmitry A. Kazakovhttp://www.dmitry-kazakov.de