Path: csiph.com!usenet.pasdenom.info!weretis.net!feeder4.news.weretis.net!feeds.phibee-telecom.net!newsfeed.xs4all.nl!newsfeed5.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail
Return-Path: <gandalf@shopzeus.com>
X-Original-To: python-list@python.org
Delivered-To: python-list@mail.python.org
X-Spam-Status: OK 0.074
X-Spam-Evidence: '*H*': 0.85; '*S*': 0.00; 'correct,': 0.09; 'immutable': 0.09; 'read()': 0.09; 'threads,': 0.09; 'threads.': 0.09; 'subject:failed': 0.16; 'threads': 0.16; 'fixed.': 0.17; 'memory': 0.18; 'idea': 0.24; 'least': 0.25; 'header:In-Reply- To:1': 0.25; 'header:User-Agent:1': 0.26; 'once,': 0.29; 'usually': 0.30; 'saves': 0.30; 'problem.': 0.32; 'file': 0.32; 'much.': 0.33; 'to:addr:python-list': 0.33; 'agree': 0.34; 'done': 0.34; 'open': 0.35; 'explain': 0.36; 'but': 0.36; 'too': 0.36; 'two': 0.37; 'data': 0.37; 'subject:: ': 0.38; 'easier': 0.38; 'object': 0.38; 'to:addr:python.org': 0.39; 'received:192': 0.39; 'received:192.168': 0.40; 'subject:-': 0.40; 'share': 0.61; 'first': 0.61; 'between': 0.63; 'different': 0.63; 'our': 0.65; 'protect': 0.69; 'received:204': 0.72; 'demand.': 0.91; 'hands': 0.97
Date: Thu, 02 Aug 2012 12:14:14 +0200
From: Laszlo Nagy <gandalf@shopzeus.com>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120714 Thunderbird/14.0
MIME-Version: 1.0
To: python-list@python.org
Subject: Re: CRC-checksum failed in gzip
References: <CAF_E5JahAZ4w3em_aqBbx63pxiTU-nqtRLZWb5_jRQr2yqhRWA@mail.gmail.com> <50190ED6.1040100@shopzeus.com> <mailman.2825.1343826107.4697.python-list@python.org> <501956a7$0$29978$c3e8da3$5496439d@news.astraweb.com> <CAF_E5JZ5=JkR3R=Y9VQ+sp_hCOODMaz2zHRwYVqbexNOCDNX0A@mail.gmail.com> <501961C7.1050405@shopzeus.com> <CAF_E5JamtuPZunDFMaknmBsczRzg7UkxzMsVdy122aQJOrGVKA@mail.gmail.com> <mailman.2845.1343843853.4697.python-list@python.org> <3hrpe9-hbi.ln1@satorlaser.homedns.org>
In-Reply-To: <3hrpe9-hbi.ln1@satorlaser.homedns.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
X-BeenThere: python-list@python.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: General discussion list for the Python programming language <python-list.python.org>
List-Unsubscribe: <http://mail.python.org/mailman/options/python-list>, <mailto:python-list-request@python.org?subject=unsubscribe>
List-Archive: <http://mail.python.org/pipermail/python-list>
List-Post: <mailto:python-list@python.org>
List-Help: <mailto:python-list-request@python.org?subject=help>
List-Subscribe: <http://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe>
Newsgroups: comp.lang.python
Message-ID: <mailman.2862.1343902460.4697.python-list@python.org>
Lines: 16
NNTP-Posting-Host: 2001:888:2000:d::a6
X-Trace: 1343902460 news.xs4all.nl 6843 [2001:888:2000:d::a6]:42169
X-Complaints-To: abuse@xs4all.nl
Xref: csiph.com comp.lang.python:26393


> Technically, that is correct, but IMHO its complete nonsense to share 
> the file object between threads in the first place. If you need the 
> data in two threads, just read the file once and then share the 
> read-only, immutable content. If the file is small or too large to be 
> held in memory at once, just open and read it on demand. This also 
> saves you from having to rewind the file every time you read it.
>
> Am I missing something?
We suspect that his program reads the same file object from different 
threads. At least this would explain his problem. I agree with you - 
usually it is not a good idea to share a file object between threads. 
This is what I told him the first time. But it is not in our hands - he 
already has a program that needs to be fixed. It might be easier for him 
to protect read() calls with a lock. Because it can be done 
automatically, without thinking too much.