From: David Botton <David@Botton.com>
Subject: Re: win32ada design question/problem
Date: 1998/11/19
Date: 1998-11-19T00:00:00+00:00 [thread overview]
Message-ID: <365455D5.9A1D0B23@Botton.com> (raw)
In-Reply-To: 365454A8.EFCA84F9@elca-matrix.ch
Mats Weber 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).
>
> so you have to do this instead:
>
> C_Function(S(S'first)'Unchecked_Access);
>
> which does not make clear that S is passed as a whole.
>
> The second problem is that people see a compiler message like "object
> has accessibility level deeper than access type" and instead of using
> 'Unchecked_Access, they move the declaration to the library level and
> create non task safe code. I am not making this up, see the samples
> directory that comes with the win32ada binding.
Why wouldn't you use:
function C_Function ( X : C.char_array ) returns C.Int;
-- int c_function ( char* x);
pragma Import (C, C_Function);
From my understanding it will be passed by_referrence, ie. as a char *
For other record types
type Z is record
a : C.Int;
end record;
pragma Convention(C, Z);
procedure C_Procedure ( Y : Z );
-- void* c_procedure ( z* y );
pragma Import (C, C_Procedure);
David Botton
next prev parent 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 ` 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
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 ` Mats Weber
1998-11-19 0:00 ` David Botton [this message]
1998-11-19 0:00 ` Mats Weber
1998-11-23 0:00 ` Marin David Condic
1998-11-19 0:00 ` dennison
1998-11-19 0:00 ` David Botton
1998-11-27 0:00 ` Roga Danar
-- 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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