RE: RPG400-L Digest V2 #357

["Richard Jackson" <richardjackson@xxxxxxxxxxxxxxxxxx>]

look at the virtual address of the object in storage.  If the low-order byte
of the address is a zero, the object is 16-byte aligned.  If the low order
address byte is even (0, 2, 4, ...) the object is at least 2-byte aligned.
And so forth.

Richard Jackson
mailto:richardjackson@richardjackson.net
http://www.richardjacksonltd.com
Voice: 1 (303) 808-8058
Fax:   1 (303) 663-4325

-|-----Original Message-----
-|From: owner-rpg400-l@midrange.com [mailto:owner-rpg400-l@midrange.com]On
-|Behalf Of Peter Dow
-|Sent: Tuesday, October 10, 2000 1:27 PM
-|To: RPG400-L@midrange.com
-|Subject: Re: RPG400-L Digest V2 #357
-|
-|
-|Hi Ken,
-|
-|How can one tell what boundary a data structure, or any other
-|field for that
-|matter, is aligned on?
-|
-|Curious,
-|Peter Dow
-|Dow Software Services, Inc.
-|909 425-0194 voice
-|909 425-0196 fax
-|
-|----- Original Message -----
-|From: "Sims, Ken" <KSIMS@SOUTHERNWINE.com>
-|To: <rpg400-l@midrange.com>
-|Sent: Tuesday, October 10, 2000 10:08 AM
-|Subject: RE: RPG400-L Digest V2 #357
-|
-|
-|> Hi Peter -
-|>
-|> >The V4R4 RPG ILE manual says:
-|>  ...
-|> >The position they're talking about is the position of the
-|subfield within
-|a
-|> >data structure, so if the above is true, one would have to assume that
-|the
-|> >data structure begins on a 16-byte boundary. It would be nice if they
-|> >explicitly said that, and assured us it won't change from release to
-|> >release.
-|>
-|> Based on my experimentation, since the compiler rejects pointers defined
-|> with from/to positioning that is not on a 16-byte boundary, it appears
-|that
-|> data structures with pointers are always aligned on a 16-byte boundary.
-|> Only pointer fields *have* to be aligned on a 16-byte boundary.
-| No other
-|> fields *have* to be aligned on any particular boundary, and no other
-|fields
-|> need a 16-byte alignment for best performance; therefore there
-|is nothing
-|to
-|> imply that any data structure not containing pointers is aligned on a
-|> 16-byte boundary.
-|>
-|> The data structure being discussed in this thread does not
-|contain actual
-|> pointer fields since it is an externally described data structure using
-|> character fields to hold pointers, therefore there is no reason
-|to assume
-|> any particular alignment.
-|>
-|> The use of the ALIGN keyword does not imply changing the data structure
-|> itself to ANY particular byte alignment, only to adding padding between
-|> individual fields in the data structure to align float, signed integer,
-|and
-|> unsigned integer fields for performance.
-|>
-|> Ken
-|> Southern Wine and Spirits of Nevada, Inc.
-|> Opinions expressed are my own and do not necessarily represent the views
-|of
-|> my employer or anyone in their right mind.
-|>
-|> +---
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