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From: "David Botton" <dbotton@hotmail.com>
Subject: Re: win32ada design question/problem
Date: 1998/11/19
Message-ID: <732kpc$15sk$1@news.gate.net>#1/1
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Newsgroups: comp.lang.ada
Date: 1998-11-19T00:00:00+00:00
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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.
>