Path: csiph.com!newsfeed.hal-mli.net!feeder3.hal-mli.net!newsfeed.hal-mli.net!feeder1.hal-mli.net!newsfeed.xs4all.nl!newsfeed5.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 0.000 X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'url:sourceforge': 0.03; 'subject:: [': 0.03; 'exit': 0.07; 'missed': 0.09; 'subject:How': 0.09; 'may,': 0.09; 'port,': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'thread,': 0.09; 'timeout': 0.09; 'thread': 0.11; 'aug': 0.13; 'sat,': 0.15; 'blocks': 0.16; 'cleanly': 0.16; 'daemon,': 0.16; 'encountered.': 0.16; 'for,': 0.16; 'no...': 0.16; 'received:80.91.229.3': 0.16; 'received:plane.gmane.org': 0.16; 'why,': 0.16; 'bytes': 0.17; 'subject:] ': 0.19; 'pending': 0.20; 'putting': 0.20; 'runs': 0.22; 'header:X-Complaints-To:1': 0.28; '(unless': 0.29; 'sleep': 0.29; 'could': 0.32; 'says': 0.33; '+0200,': 0.33; 'url:home': 0.33; 'to:addr:python-list': 0.33; 'data,': 0.35; 'open': 0.35; 'there': 0.35; 'received:org': 0.36; 'but': 0.36; 'data.': 0.36; 'test': 0.36; 'should': 0.36; 'charset :us-ascii': 0.36; 'data': 0.37; 'behind': 0.38; 'some': 0.38; 'sure': 0.38; 'to:addr:python.org': 0.39; 'header:Received:5': 0.40; 'think': 0.40; 'close': 0.63; 'different': 0.63; 'serial': 0.66; 'subject:wait': 0.84; 'dennis': 0.91; 'killed': 0.91 X-Injected-Via-Gmane: http://gmane.org/ To: python-list@python.org From: Dennis Lee Bieber Subject: Re: [Newbie] How to wait for asyncronous input Date: Sat, 11 Aug 2012 14:21:30 -0400 Organization: > Bestiaria Support Staff < References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Gmane-NNTP-Posting-Host: adsl-76-253-105-172.dsl.klmzmi.sbcglobal.net X-Newsreader: Forte Agent 3.3/32.846 X-No-Archive: YES X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.12 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: 33 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1344709296 news.xs4all.nl 6987 [2001:888:2000:d::a6]:60669 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:26922 On Sat, 11 Aug 2012 09:07:51 +0200, pozz declaimed the following in gmane.comp.python.general: > Il 11/08/2012 01:12, Dennis Lee Bieber ha scritto: > > What you apparently missed is that serial.read() BLOCKs until data > > is available (unless the port was opened with a read timeout set). > > [...] > > > > serial.read() may, there for, be using select() behind the scenes. > > Hmm..., so I could open the serial port with timeout=0 so the read(), > that runs in a different thread, would block forever, so putting the > thread in a sleep state until some bytes arrive. No... timeout=0 says "never block" -- it will return immediately with or without any data. timeout=None is "block until data arrives" http://pyserial.sourceforge.net/pyserial_api.html#classes > > When the main thread wants to close the serial port, the receiving > thread can be killed (I don't know why, but I think it will be possible). If the thread is a daemon, it should die when the main program does. Not sure what happens on port closure -- the pending read may return with no data, which would be a condition the thread could test for and exit cleanly when encountered. -- Wulfraed Dennis Lee Bieber AF6VN wlfraed@ix.netcom.com HTTP://wlfraed.home.netcom.com/