From 8540018056311697248
X-Google-Thread: f78e5,99f1efda99846e15
X-Google-Attributes: gidf78e5,public
X-Google-Language: ENGLISH,ASCII-7-bit
Path: g2news1.google.com!news2.google.com!news.maxwell.syr.edu!border1.nntp.dca.giganews.com!nntp.giganews.com!peer01.cox.net!cox.net!peer-uk.news.demon.net!kibo.news.demon.net!mutlu.news.demon.net!news.demon.co.uk!demon!stump.algebra.com!devnull
From: technews@kangaroologic.com ("Jonathan Turkanis")
Newsgroups: comp.std.c++
Subject: Re: Custom allocator for vector
Date: Thu, 26 Aug 2004 06:54:59 GMT
Lines: 30
Sender: mail2news@demon.net
Approved: fjh@cs.mu.oz.au (Fergus Henderson , moderator of comp.std.c++)
Message-ID: <2p4rb0FgvscnU1@uni-berlin.de>
References: <2ns6efF45gptU1@uni-berlin.de> <5bp3i05gbil94hkm6je61ehubm3jv2om5d@4ax.com>
NNTP-Posting-Host: news.news.demon.net
X-Trace: news.demon.co.uk 1093503304 25447 158.152.254.254 (26 Aug 2004 06:55:04 GMT)
X-Complaints-To: abuse@demon.net
NNTP-Posting-Date: Thu, 26 Aug 2004 06:55:04 +0000 (UTC)
X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov)
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441
X-Priority: 3
X-Spam-Checker-Version: SpamAssassin 2.64-mulga_r1 (2004-01-11) on 
	mulga.cs.mu.OZ.AU
X-Orig-X-Trace: news.uni-berlin.de gqdg264YwxAX9ZuVegnwageRWQihAqUw6q7q+FH3hmXLipiP7b
X-Spam-Status: No, hits=-2.5 required=5.0 tests=AWL,BAYES_00,PRIORITY_NO_NAME 
	autolearn=no version=2.64-mulga_r1
X-MSMail-Priority: Normal
X-Received: (from fjh@localhost)
	by mulga.cs.mu.OZ.AU (8.12.10+Sun/8.12.9/Submit) id i7Q6sxEY009511;
	Thu, 26 Aug 2004 16:54:59 +1000 (EST)
X-Path: comp-std-cpp-robomod!not-for-mail
X-Delivered-To: std-c++@ucar.edu
X-Authentication-Warning: mulga.cs.mu.OZ.AU: fjh set sender to devnull@stump.algebra.com using -f
X-Newsreader: Microsoft Outlook Express 6.00.2800.1437
X-Newsgroups: comp.std.c++
Xref: g2news1.google.com comp.std.c++:2185


"tom_usenet" <tom_usenet@hotmail.com> wrote:
> On Tue, 10 Aug 2004 17:18:53 GMT, alexvn@big-foot.com ("Alex
Vinokur")

> >The more specific question: do we need construct() and destroy()
indeed? For instance, g++ doesn't use them.
>
> We do need them for special pointer types, yes. e.g. a pointer might
> be an int (for an offset), in which case new((void*)anint) T(val) is
> just not going to work; the allocator will need something like:
>
> void myallocator::construct(pointer p, const_reference value)
> {
>   T* ptr = base_address + p;
>   new ((void*)ptr) value_type(value);
> }

How does this work if you've used allocate() to allocate memory for an
array of T?

Jonathan


---
[ comp.std.c++ is moderated.  To submit articles, try just posting with ]
[ your news-reader.  If that fails, use mailto:std-c++@ncar.ucar.edu    ]
[              --- Please see the FAQ before posting. ---               ]
[ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html                       ]