From: Ken Garlington <garlingtonke@lmtas.lmco.com>
Subject: Re: Rules for Representation of Subtypes
Date: 1996/10/11
Date: 1996-10-11T00:00:00+00:00 [thread overview]
Message-ID: <325E5259.6D3E@lmtas.lmco.com> (raw)
In-Reply-To: 9610101740.AA09737@most
W. Wesley Groleau (Wes) wrote:
> [snip]
> I haven't used Verdix in 18 months, but if I remember right, it allowed
> source to be larger than target WITH a warning. Similar memory for
> VAX Ada, though I haven't used that in five years. Unfortunately, many
> coders suppress warnings because "there are so @$#^$%^*&$ many of them,
> they just hide the real problems."
DEC Ada v3.2 still permits dissimilar sizes. Here's the code I tried:
with Unchecked_Conversion;
package UC_Pkg is
type S_Type is range 0 .. 16#7FFF_FFFF#;
for S_Type'Size use 32;
type T_Type is range 0 .. 10;
for T_Type'Size use 4;
function S_to_T is new Unchecked_Conversion (S_Type, T_Type);
S : S_Type := 16#FFFF#;
T : T_Type;
end;
with UC_Pkg; use UC_Pkg;
with Text_IO;
procedure UC is
begin
T := S_to_T(S); -- examining T in the DEC debugger after this statement
-- shows T to be equal to 16#F#.
Text_IO.Put_Line(T_Type'Image(T)); -- prints "-1" (16#F# as two's complement)
end;
In Ada 83, there's an AI that permits the unchecked conversion to be rejected,
but it's not required.
>
> ---------------------------------------------------------------------------
> W. Wesley Groleau (Wes) Office: 219-429-4923
> Hughes Defense Communications (MS 10-40) Home: 219-471-7206
> Fort Wayne, IN 46808 (Unix): wwgrol@pseserv3.fw.hac.com
> ---------------------------------------------------------------------------
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next prev parent reply other threads:[~1996-10-11 0:00 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
1996-10-10 0:00 Rules for Representation of Subtypes W. Wesley Groleau (Wes)
1996-10-10 0:00 ` Robert Dewar
1996-10-11 0:00 ` Ken Garlington [this message]
-- strict thread matches above, loose matches on Subject: below --
1996-10-03 0:00 Franco Mazzanti
1996-10-03 0:00 ` Robert A Duff
1996-10-02 0:00 Franco Mazzanti
1996-10-03 0:00 ` Robert A Duff
1996-09-28 0:00 Robert Dewar
1996-09-30 0:00 ` Keith Thompson
1996-09-28 0:00 Robert Dewar
1996-09-29 0:00 ` Robert A Duff
1996-09-29 0:00 ` Matthew Heaney
1996-09-29 0:00 ` Robert Dewar
1996-09-30 0:00 ` Art Schwarz
1996-09-30 0:00 ` Robert A Duff
1996-10-01 0:00 ` Larry Kilgallen
1996-10-01 0:00 ` Brian R. Hanson
1996-10-01 0:00 ` Robert A Duff
1996-09-28 0:00 Robert Dewar
1996-09-29 0:00 ` Robert A Duff
1996-09-29 0:00 ` Matthew Heaney
1996-09-22 0:00 Matthew Heaney
1996-09-23 0:00 ` David C. Hoos, Sr.
1996-09-23 0:00 ` Robert A Duff
1996-09-23 0:00 ` Samuel T. Harris
1996-09-26 0:00 ` David C. Hoos, Sr.
1996-09-24 0:00 ` Robert Dewar
1996-09-26 0:00 ` Keith Thompson
1996-09-26 0:00 ` Matthew Heaney
1996-09-27 0:00 ` Robert Dewar
1996-09-27 0:00 ` Robert A Duff
1996-09-27 0:00 ` Robert Dewar
1996-09-27 0:00 ` Robert A Duff
1996-09-24 0:00 ` Robert Dewar
1996-09-23 0:00 ` Robert A Duff
1996-09-24 0:00 ` Matthew Heaney
1996-09-26 0:00 ` Robert A Duff
1996-09-26 0:00 ` Larry Kilgallen
1996-09-27 0:00 ` Robert A Duff
1996-09-27 0:00 ` Mark A Biggar
1996-09-30 0:00 ` Robert A Duff
1996-10-01 0:00 ` Larry Kilgallen
1996-10-01 0:00 ` Robert A Duff
1996-10-01 0:00 ` Samuel Tardieu
1996-10-01 0:00 ` Ken Garlington
1996-09-28 0:00 ` Larry Kilgallen
1996-09-29 0:00 ` Robert A Duff
1996-09-29 0:00 ` Larry Kilgallen
1996-09-29 0:00 ` Matthew Heaney
1996-09-30 0:00 ` Robert A Duff
1996-10-01 0:00 ` Ken Garlington
1996-10-02 0:00 ` Robert A Duff
1996-10-02 0:00 ` Ken Garlington
1996-10-06 0:00 ` Robert Dewar
1996-09-29 0:00 ` Matthew Heaney
1996-09-30 0:00 ` Robert A Duff
1996-09-30 0:00 ` Robert Dewar
1996-09-30 0:00 ` Matthew Heaney
1996-10-03 0:00 ` Robert Dewar
1996-09-27 0:00 ` Matthew Heaney
1996-09-27 0:00 ` Robert A Duff
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