Path: csiph.com!eternal-september.org!feeder.eternal-september.org!feeds.phibee-telecom.net!newsfeed.xs4all.nl!newsfeed8.news.xs4all.nl!news.tele.dk!news.tele.dk!small.news.tele.dk!newsgate.cistron.nl!newsgate.news.xs4all.nl!nzpost1.xs4all.net!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; 'url:pypi': 0.03; 'cc:addr :python-list': 0.09; 'received:openend.se': 0.09; 'received:theraft.openend.se': 0.09; 'separately': 0.09; 'subject:python': 0.14; 'wed,': 0.15; 'argument.': 0.16; 'cc:addr:lac': 0.16; 'cc:addr:openend.se': 0.16; 'ctypes.': 0.16; 'from:addr:lac': 0.16; 'from:addr:openend.se': 0.16; 'from:name:laura creighton': 0.16; 'libs': 0.16; 'message- id:@fido.openend.se': 0.16; 'received:fido': 0.16; 'received:fido.openend.se': 0.16; 'this).': 0.16; 'laura': 0.18; 'load': 0.20; '2015': 0.20; 'cc:addr:python.org': 0.20; 'cc:2**1': 0.22; 'ctypes': 0.22; 'libraries': 0.22; 'see:': 0.22; 'sep': 0.22; "haven't": 0.24; "doesn't": 0.26; '(which': 0.26; 'loads': 0.29; 'once,': 0.29; 'received:se': 0.29; 'them?': 0.29; 'thread,': 0.29; 'cc:no real name:2**1': 0.29; 'knows': 0.32; 'anybody': 0.32; 'maybe': 0.33; 'problem': 0.33; 'url:python': 0.33; 'done,': 0.33; 'loading': 0.33; 'file': 0.34; 'problem.': 0.35; 'but': 0.36; 'should': 0.36; 'instead': 0.36; 'there': 0.36; 'url:org': 0.36; 'depends': 0.36; 'subject:: ': 0.37; 'two': 0.37; 'wanted': 0.37; 'mean': 0.38; 'ever': 0.60; 'header:Message-Id:1': 0.61; 'first?': 0.84; 'header:In-reply-to:1': 0.84; 'url:ml': 0.84 To: "chenchao@inhand.com.cn" cc: python-list@python.org, lac@openend.se From: Laura Creighton Subject: Re: python how to load multiple C libraries In-reply-to: <55F937D6.6040104@inhand.com.cn> References: <55F937D6.6040104@inhand.com.cn> Comments: In-reply-to "chenchao@inhand.com.cn" message dated "Wed, 16 Sep 2015 17:35:18 +0800." MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-ID: <17721.1442409221.1@fido> Content-Transfer-Encoding: quoted-printable Date: Wed, 16 Sep 2015 15:13:41 +0200 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.3.9 (theraft.openend.se [82.96.5.2]); Wed, 16 Sep 2015 15:13:51 +0200 (CEST) X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.20+ 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: 37 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1442409253 news.xs4all.nl 23782 [2001:888:2000:d::a6]:33518 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:96676 In a message of Wed, 16 Sep 2015 17:35:18 +0800, "chenchao@inhand.com.cn" = write s: >hi: >I encountered a problem. I use ctypes load multiple C libraries, but = >the libraries have dependence each other.So, how can i load these = >libraries. For example, I have two libraries:A=E3=80=81B, but A depends o= n B, B = >depends on A. So how do I load them? Is there anybody know how to do it? I don't know how to do this with ctypes (which doesn't mean it cannot be done, just that I haven't ever wanted to do this). What happens if you make a small file that loads both separately and loads that one first? It may be that you can get what you want with by loading the first lib RTLD_LAZY instead of RTLD_NOW. see: http://stackoverflow.com/questions/22591472/dyanamic-library-linking-by-rt= ld-lazy see: this very old thread, maybe CTypes knows about it now. http://osdir.com/ml/python.ctypes/2006-10/msg00029.html But I have never tried. These days I used cffi instead of ctypes. If you use cffi https://pypi.python.org/pypi/cffi there should not be any problem if you use ffi.set_source(), = only once, but mentioning both libs in the libraries=3D[...] argument. Laura