* Re: pointers to unconstrained arrays
[not found] <346FC90F.3EEC@vsl.com.au>
@ 1997-11-16 0:00 ` Matthew Heaney
1997-11-17 0:00 ` Keith Thompson
0 siblings, 1 reply; 2+ messages in thread
From: Matthew Heaney @ 1997-11-16 0:00 UTC (permalink / raw)
In article <346FC90F.3EEC@vsl.com.au>, Andrew Kelly <andrewk@vsl.com.au> wrote:
>procedure allocate_buffer (
> low, high : in integer;
> buffer_address : system.address;
> buffer_ptr : out buffer_ptr_type) is
[snip]
> -- return pointer to buffer
> buffer_ptr := buffer'access;
>end allocate_buffer;
You can't do this, and for a very good reason. You're pointing to a
locally-declared buffer.
>
>
>
>-- unconstrained_array_ptr_test
> my_buffer_ptr : buffer_ptr_type;
>
>begin
> allocate_buffer(1, 5, system.ItoA(16#B000#), my_buffer_ptr);
Why not do this
Buffer : Buffer_Type (1 .. 5);
for Buffer'Address use System.ItoA (16#B000#);
begin
and then refer to Buffer directly? If you're going to call Allocate_Buffer
with hard-coded parameters, and declare a buffer access type to indirectly
refer to the buffer, you might as well just declare a buffer directly,
using the parameters you passed to the call.
--------------------------------------------------------------------
Matthew Heaney
Software Development Consultant
<mailto:matthew_heaney@acm.org>
(818) 985-1271
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: pointers to unconstrained arrays
1997-11-16 0:00 ` pointers to unconstrained arrays Matthew Heaney
@ 1997-11-17 0:00 ` Keith Thompson
0 siblings, 0 replies; 2+ messages in thread
From: Keith Thompson @ 1997-11-17 0:00 UTC (permalink / raw)
Matthew Heaney (mheaney@ni.net) wrote:
[...]
> Why not do this
>
> Buffer : Buffer_Type (1 .. 5);
> for Buffer'Address use System.ItoA (16#B000#);
> begin
>
> and then refer to Buffer directly?
Good idea, except that there's no ItoA function in System (though some
implementations may (unwisely, IMHO) provide such a function).
Try System.Storage_Elements.To_Address.
--
Keith Thompson (The_Other_Keith) kst@cts.com <*>
^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H
San Diego, California, USA
"Simba, you have forgotten me. I am your father. This is CNN." -- JEJ
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1997-11-16 0:00 ` pointers to unconstrained arrays Matthew Heaney
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