From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,6c13cc000274246b
X-Google-Attributes: gid103376,public
From: dewar@merv.cs.nyu.edu (Robert Dewar)
Subject: Re: Please Help.
Date: 1997/09/18
Message-ID: <dewar.874604078@merv>#1/1
X-Deja-AN: 273616477
References: <01bcbcde$f8a425c0$ca70fe8c@default> <dewar.873989183@merv>
 <5vaude$q20$1@goanna.cs.rmit.edu.au> <5vbiid$luu$1@goanna.cs.rmit.edu.au>
 <34197042.7CFC@gsfc.nasa.gov> <dewar.874165401@merv>
 <341D4041.4AF8@gsfc.nasa.gov> <dewar.874434176@merv>
 <342005BE.5C4E@gsfc.nasa.gov>
Organization: New York University
Newsgroups: comp.lang.ada
Date: 1997-09-18T00:00:00+00:00
List-Id: <comp.lang.ada>



<<The downside is heap fragmentation, which will bite you just when it
  costs the most to fix. Controlled types can guarantee no dangling
  pointers; they do not guarantee no heap fragmentation. For that you need
  compacting storage pools (or very careful use of Unbounded_Strings).

  Is there a requirement in Ada 95 to document whether the
  Unbounded_Strings implementation is compacting? This would be useful
  information; I haven't seen it in Annex M for ObjectAda, but I don't
  believe I've read the whole thing.>>


Well these days on typical machines, fragmentation just translates into
poorer performance because of more paging. But compacting may or may not
help to reduce paging. It is not a clear call at all

There is no requirement for documenting this, since there is no imagination
of compacting being an issue. (there is also no requirement to document
whether your storage allocator reads the CMOS clock, or takes locks, or
makes direct BIOS calls, or allocates more than it needs to, or anything
else!)