Path: csiph.com!usenet.pasdenom.info!weretis.net!feeder4.news.weretis.net!rt.uk.eu.org!newsfeed.xs4all.nl!newsfeed2.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.001 X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'python,': 0.02; 'subject:Windows': 0.02; 'subject:Python': 0.06; '64-bit': 0.07; 'memory.': 0.07; '32-bit': 0.09; 'differing': 0.09; 'pointers': 0.09; 'python': 0.11; "wouldn't": 0.14; 'windows': 0.15; '4gb': 0.16; 'backwards': 0.16; 'compiler.': 0.16; 'longs': 0.16; 'object).': 0.16; 'subject: \n ': 0.16; 'subject:between': 0.16; 'subject:bit': 0.16; 'underlying': 0.16; 'sat,': 0.16; 'wrote:': 0.18; 'bit': 0.19; '(the': 0.22; 'to:name:python-list@python.org': 0.22; 'install': 0.23; 'specify': 0.24; 'versions': 0.24; "haven't": 0.24; 'looks': 0.24; 'header:In-Reply-To:1': 0.27; 'installed': 0.27; 'message-id:@mail.gmail.com': 0.30; 'linux.': 0.31; 'linux': 0.33; 'running': 0.33; 'subject:the': 0.34; 'could': 0.34; 'received:209.85': 0.35; 'received:google.com': 0.35; 'version': 0.36; 'really': 0.36; 'interact': 0.36; 'ram': 0.36; 'possible': 0.36; 'subject:?': 0.36; 'hi,': 0.36; 'searching': 0.37; 'received:209': 0.37; 'to:addr:python-list': 0.38; 'pm,': 0.38; 'little': 0.38; 'expect': 0.39; 'to:addr:python.org': 0.39; 'how': 0.40; 'even': 0.60; 'address': 0.63; 'more': 0.64; 'hours': 0.66; 'between': 0.67; 'anything.': 0.68; 'max.': 0.84; 'rolls': 0.84; 'whereas': 0.91 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:content-type:content-transfer-encoding; bh=I8UgNpqsoxbii1BqX1ibVUWBAG+9/KCseFsLcxTkH6A=; b=XYTmC2tUJVNXiUsQ/55gmyeVm7yS5A5vZr+QUCKBixhNO5e2kDOth/yFTMQYOTITYf 8Y1tU6GEax7qtSrewFZ/uGV3gSmOW4+3o/vwrxXds6WHvzBcEful2CloUmYyCq8sA+Wb SIkXBpS2+QnqayCJDyjm0Xq5DXUZaVayfj+g3bB+wYqtCHqCAjDmD1BVDgIHXFngXsJ7 sqb2papaTY25wdUHe0+tybgjZRxX5v4Hnj4DaI2xXjjYBc2OJRs6T+B9oOicrjrXwoA1 x9eZzrkwFQPbVS4pd6qoijUoB6BglG4cfrOHTq80SvxtFmT6iIRLvzV6ijpHQG/y5Px+ j0Vw== X-Gm-Message-State: ALoCoQk0B9xAzbWhm1iU+KUN9hN+dcdjdw+zZpLhZiIeSL2a/mQd80fqISixaNOpy4DIU+V/twxKPY/oBtTltJn7od8UvGg6pgYJzJ2YbcBPTOltr21JKJ6qBJsT0xPFBq/Gg65IIlOc X-Received: by 10.236.46.225 with SMTP id r61mr32343763yhb.107.1399812823660; Sun, 11 May 2014 05:53:43 -0700 (PDT) X-Received: by 10.236.46.225 with SMTP id r61mr32343754yhb.107.1399812823562; Sun, 11 May 2014 05:53:43 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: From: Benjamin Kaplan Date: Sun, 11 May 2014 05:53:23 -0700 Subject: Re: What is the difference between 32 and 64 bit Python on Windows 7 64 bit? To: "python-list@python.org" Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Junkmail-Whitelist: YES (by domain whitelist at mpv2.tis.cwru.edu) X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Newsgroups: comp.lang.python Message-ID: Lines: 35 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1399813207 news.xs4all.nl 2857 [2001:888:2000:d::a6]:51516 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:71315 On Sat, May 10, 2014 at 11:56 PM, Ross Gayler wrote: > > Hi, > > I want to install Python on a PC with 16GB of RAM and the 64 bit version = of Windows 7. > I want Python to be able to use as much as possible of the RAM. > > When I install the 64 bit version of Python I find that sys.maxint =3D=3D= 2**31 - 1 > Whereas the Pythpon installed on my 64 bit linux system returns sys.maxin= t =3D=3D 2**63 - 1. > That comes from the underlying C implementation. 64-bit MSVC still has long int as 32-bit. You need to specify long long int to get a 64-bit number even on a 64-bit compiler. Microsoft is a little nuts on the backwards compatiblity. > It looks to me as though 32 and 64 bit versions of Python on 64 bit Windo= ws are both really 32 bit Python, differing only in how they interact with = Windows. So I wouldn't expect 64 bit Python running on 64 bit Windows to al= low the large data struictures I could have with 64 bit Python running on 6= 4 bit linux. > > Is that true?I have spent a couple of hours searching for a definitive de= scription of the difference between the 32 and 64 bit versions of Python fo= r Windows and haven't found anything. > long int (the size of an integer) !=3D size_t (the size of an object). 64-bit Python still uses 64-bit pointers so it can still address more than 4GB of memory. It just rolls over into longs after 32-bit int max instead of after 64-bit int max.