From: Florian Weimer <fw@deneb.enyo.de>
Subject: Re: AdaYY wish list from current projects
Date: 23 Feb 2001 16:04:21 +0100
Date: 2001-02-23T16:04:21+01:00 [thread overview]
Message-ID: <87zofdzbii.fsf@deneb.enyo.de> (raw)
In-Reply-To: slrn99cs08.ju.lutz@taranis.iks-jena.de
lutz@iks-jena.de (Lutz Donnerhacke) writes:
> Yep. I talk about values crossing a storage_element boundary and you
> talk about invalid values.
Oh, sorry.
I still have to see some code which shows that record representation
clauses are practicall even if the components occupy multiple storage
elements. ;-)
> procedure t is
> type pstring(len : Integer) is record
> data : String (1 .. len);
> end record;
> pragma Pack (pstring); -- record representation clause not possible
>
> ex : pstring; -- Won't work;
> for ex'Address use 16#00000#;
> begin
> Put_Line (Integer'Image (ex.len) & " => " & ex.data);
> end t;
Perhaps you want to use a constrained integer type in conjunction with
a record discriminant with a default expression?
> >> The problem escaped from a 'multiprotocol router'. Please try to map a IPv4
> >> header incl. payload and IP-header options.
> >
> >Ah. Well, obviously, you can't use a single record in this case.
>
> So I'm stuck to implement gather-scatter from the beginning. ;-/
Why that? You can still have the records in consecutive storage
locations, but you have to do some manual address calculations.
next prev parent reply other threads:[~2001-02-23 15:04 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-02-20 20:50 AdaYY wish list from current projects Lutz Donnerhacke
2001-02-22 11:08 ` Florian Weimer
2001-02-22 13:02 ` Lutz Donnerhacke
2001-02-23 9:30 ` Florian Weimer
2001-02-23 10:12 ` Lutz Donnerhacke
2001-02-23 13:54 ` Florian Weimer
2001-02-23 14:16 ` Lutz Donnerhacke
2001-02-23 15:04 ` Florian Weimer [this message]
2001-02-23 15:15 ` Lutz Donnerhacke
2001-02-23 16:21 ` Florian Weimer
2001-02-23 16:31 ` Lutz Donnerhacke
2001-02-23 17:25 ` Florian Weimer
2001-02-26 11:22 ` Lutz Donnerhacke
2001-02-23 19:06 ` tmoran
2001-02-26 11:20 ` Lutz Donnerhacke
2001-02-23 19:06 ` tmoran
2001-02-26 11:21 ` Lutz Donnerhacke
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