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From: cjrgreen@concentric.net (Christopher Green)
Subject: Re: Alternate to Unchecked_Conversion - Portable?
Date: 1999/02/23
Date: 1999-02-23T00:00:00+00:00	[thread overview]
Message-ID: <36d3bf1f.1891152@nntp.concentric.net> (raw)
In-Reply-To: 7avpi0$jke$1@nnrp1.dejanews.com

On Wed, 24 Feb 1999 02:52:52 GMT, robert_dewar@my-dejanews.com wrote:

>In article <36d2638e.6427631@nntp.concentric.net>,
>  cjrgreen@concentric.net (Christopher Green) wrote:
>> It is primarily useful in situations in which alternative
>> implementations end up causing a bitwise copy.  If
>> the object to be converted is large, or the conversion
>> must be done many times, this can be a win.
>
>This seems bogus to me. If you replace this by unchecked
>conversion of *pointers* (i.e. access values), NOT the
>items themselves, then there is no bit copying, and no
>inefficiency at all in the access.
>
>-----------== Posted via Deja News, The Discussion Network ==----------
>http://www.dejanews.com/       Search, Read, Discuss, or Start Your Own    

Unchecked conversion of C pointers to Ada access values
is, in my experience, no more portable than using address
clauses to alias structured types.  When the desired Ada
object is an instance of an unconstrained type, converting
a pointer is completely nonportable and usually impractical.

-- 
Chris Green
Advanced Technology Center
Laguna Hills, California




  reply	other threads:[~1999-02-23  0:00 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1999-02-21  0:00 Alternate to Unchecked_Conversion - Portable? Steve Doiel
1999-02-21  0:00 ` Steve Quinlan
1999-02-22  0:00   ` robert_dewar
1999-02-21  0:00 ` Matthew Heaney
1999-02-22  0:00 ` robert_dewar
1999-02-22  0:00   ` Samuel Mize
1999-02-22  0:00 ` Christopher Green
1999-02-23  0:00   ` Matthew Heaney
1999-02-23  0:00     ` Samuel Mize
1999-02-24  0:00     ` robert_dewar
1999-02-25  0:00       ` Nick Roberts
1999-02-25  0:00         ` robert_dewar
1999-02-26  0:00           ` Nick Roberts
1999-02-26  0:00             ` Matthew Heaney
1999-02-27  0:00               ` Nick Roberts
1999-02-24  0:00   ` robert_dewar
1999-02-23  0:00     ` Christopher Green [this message]
1999-02-25  0:00       ` robert_dewar
1999-02-24  0:00         ` Christopher Green
1999-02-25  0:00           ` robert_dewar
1999-02-26  0:00             ` Dale Stanbrough
1999-02-26  0:00               ` Robert A Duff
1999-02-23  0:00     ` Christopher Green
1999-02-25  0:00       ` robert_dewar
1999-02-24  0:00         ` Christopher Green
1999-02-25  0:00           ` robert_dewar
1999-02-25  0:00             ` dennison
1999-02-25  0:00               ` Christopher Green
1999-02-26  0:00                 ` robert_dewar
1999-02-26  0:00                   ` Christopher Green
1999-03-01  0:00                     ` Nick Roberts
1999-03-01  0:00                       ` dewar
1999-03-01  0:00                         ` Nick Roberts
1999-02-26  0:00                 ` Tom Moran
1999-02-26  0:00                   ` robert_dewar
1999-02-26  0:00             ` Robert A Duff
1999-02-28  0:00               ` robert_dewar
1999-02-22  0:00 ` Tom Moran
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