Interfacing with C++

Interfacing with C++

[Hagi Yilmaz]

Hello,

I have a little problem in Mapping C++, char * to Ada 95 
c.strings_chars_ptr.

in C++ code :

"
....
extern "C" {void ada_call (char *x) }; // ada function I call.
. . .
char *x;
x=(char *) malloc(100);
ada_call(x);
MessageBox(x);
. . .
"

in ada code :

"
  procedure ada_call(x : in out c.strings_chars_ptr) is

  begin

    x:=New_String(Str => "xxx"); -- x changes...

  end ada_call;
. . .
"

My problem :  In C code I write the output by "MessageBox" but see incorrect 
characters are returning from Ada.

   How should I build the Interface?
   When there is a c.strings_chars_ptr with "in out" parameter,
  how can I get correct returnings from ada in such a case?
  How should be the Ada and C codes?

Can anybody help me for that? ...

Hagi Yilmaz
hagihun@hotmail.com



_________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.

Re: Interfacing with C++

[Ted Dennison]

In article <mailman.993155362.16396.comp.lang.ada@ada.eu.org>, Hagi Yilmaz
says...
>I have a little problem in Mapping C++, char * to Ada 95 
>c.strings_chars_ptr.
>
>extern "C" {void ada_call (char *x) }; // ada function I call.

>in ada code :
>  procedure ada_call(x : in out c.strings_chars_ptr) is

That's wrong. Read your Ada references (prefereably the LRM) a bit more
carefully. What you are saying with "in out c.strings_chars_ptr" is that the
program is allowed to update the value of the pointer. In order to do that in C,
you'd need a "char **" parameter. 

You are going to need to either change the C side to "char **", or the Ada side
to something like C.Chars_Array or mode "in", depending on what you really want
to do with the parameter.

---
T.E.D.    homepage   - http://www.telepath.com/dennison/Ted/TED.html
          home email - mailto:dennison@telepath.com

Interfacing with C++

[Hagi Yilmaz]

Hello,

How Can I map the "CString" in VC++ to Ada 95?

Can I pass the "CString" from VC++ as parameter to an Ada procedure or 
function.

In fact I Use at the moment the (char *) for Interface, but I have to 
allocate it from VC++ or from Ada 95 (chars_ptr) .And of course de-allocate 
it, not to cause a storage leak.

   But i thougt if i could use "CString" somehow, i would not have to deal 
with memory leaks anymore.

Can anybody help me for that? ...

Best Regards.

Hagi Yilmaz
hagihun@hotmail.com




_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp

Re: Interfacing with C++

[Peter Hend�n]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 1032 bytes --]

If you're using GNAT you might check out "Interfacing to C++" in
the reference manual.

/Peter H.
--
Peter Hend�n           http://www.algonet.se/~phenden
ICQ: 14672398
Teknisk Dokumentation AB          http://www.tdab.com

"Hagi Yilmaz" <hagihun@hotmail.com> wrote in message
news:mailman.1002744075.16878.comp.lang.ada@ada.eu.org...
> Hello,
>
> How Can I map the "CString" in VC++ to Ada 95?
>
> Can I pass the "CString" from VC++ as parameter to an Ada procedure or
> function.
>
> In fact I Use at the moment the (char *) for Interface, but I have to
> allocate it from VC++ or from Ada 95 (chars_ptr) .And of course
de-allocate
> it, not to cause a storage leak.
>
>    But i thougt if i could use "CString" somehow, i would not have to deal
> with memory leaks anymore.
>
> Can anybody help me for that? ...
>
> Best Regards.
>
> Hagi Yilmaz
> hagihun@hotmail.com
>
>
>
>
> _________________________________________________________________
> Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp
>

Re: Interfacing with C++

[David Botton]

The following works:

procedure MyString (C_String : in Interfaces.C.Char_Array) is etc.

From C/C++

CString theStr;

MyString ((LPCSTR) theStr);


What exactly are you looking to do?

David Botton



----- Original Message -----
From: "Hagi Yilmaz" <hagihun@hotmail.com>
To: <comp.lang.ada@ada.eu.org>
Sent: Wednesday, October 10, 2001 4:01 PM
Subject: Interfacing with C++


> Hello,
>
> How Can I map the "CString" in VC++ to Ada 95?
>
> Can I pass the "CString" from VC++ as parameter to an Ada procedure or
> function.
>
> In fact I Use at the moment the (char *) for Interface, but I have to
> allocate it from VC++ or from Ada 95 (chars_ptr) .And of course
de-allocate
> it, not to cause a storage leak.
>
>    But i thougt if i could use "CString" somehow, i would not have to deal
> with memory leaks anymore.
>
> Can anybody help me for that? ...
>
> Best Regards.
>
> Hagi Yilmaz
> hagihun@hotmail.com
>
>
>
>
> _________________________________________________________________
> Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp
>
> _______________________________________________
> comp.lang.ada mailing list
> comp.lang.ada@ada.eu.org
> http://ada.eu.org/mailman/listinfo/comp.lang.ada
>