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From: "David Botton" <dbotton@hotmail.com>
Subject: Re: win32ada design question/problem
Date: 1998/11/19
Date: 1998-11-19T00:00:00+00:00	[thread overview]
Message-ID: <732kpc$15sk$1@news.gate.net> (raw)
In-Reply-To: 7323td$426$1@nnrp1.dejanews.com



I believe that GNAT complies and the example would pass a pointer to the
String appropriate for C.




Would it be necessary to say



pragma Convention (c, String_Access)?




I know that it would not be necessary in GNAT, but would it be needed for
portability?



DB

>  Mats.Weber@elca-matrix.ch wrote:
>> Tom Moran wrote:
>>
>> On the other hand,
>>
>>    type String_Access is access String;
>>
>>    function C_Function (X : in String_Access);
>>
>>    C_Function(S'Unchecked_Access);
>>
>> will sometimes not work because some compilers (and that includes GNAT)
>> use fat pointers for access to unconstrained arrays (I am not saying
>> that this is bad).
>
>No, not if they follow the implementation advice.
>
>LRM B.3(63 & 67) An implementation should support the following interface
>correspondences between Ada and C. ... o  An Ada in parameter of an
>access-to-object type with designated type T is passed as a t* argument to
a
>C function, where t is the C type corresponding to the Ada type T.
>
>
>--
>T.E.D.
>









  reply	other threads:[~1998-11-19  0:00 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1998-11-13  0:00 win32ada design question/problem Mats Weber
1998-11-13  0:00 ` Tom Moran
1998-11-16  0:00   ` Mats Weber
1998-11-18  0:00     ` Tom Moran
1998-11-18  0:00       ` dennison
1998-11-19  0:00       ` Mats Weber
1998-11-19  0:00         ` dennison
1998-11-19  0:00           ` David Botton [this message]
1998-11-19  0:00         ` David Botton
1998-11-19  0:00           ` Mats Weber
1998-11-23  0:00             ` Marin David Condic
1998-11-19  0:00       ` Mats Weber
1998-11-27  0:00     ` Roga Danar
1998-11-13  0:00 ` dennison
1998-11-16  0:00   ` Stephen Leake
1998-11-16  0:00     ` Tucker Taft
1998-11-17  0:00     ` dennison
1998-11-17  0:00       ` Mats Weber
1998-11-17  0:00         ` dennison
1998-11-17  0:00           ` Mats Weber
1998-11-17  0:00           ` Tucker Taft
1998-11-18  0:00             ` Tom Moran
1998-11-18  0:00               ` dennison
  -- strict thread matches above, loose matches on Subject: below --
1998-11-19  0:00 tmoran
1998-11-19  0:00 ` dennison
1998-11-19  0:00   ` Tom Moran
1998-11-20  0:00     ` dennison
1998-11-20  0:00       ` Tom Moran
1998-11-23  0:00     ` Marin David Condic
1998-11-23  0:00       ` Mats Weber
1998-11-24  0:00         ` dennison
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