Bugs item #1439659, was opened at 2006-02-27 09:51 Message generated for change (Comment added) made by tim_one You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1439659&group_id=5470
Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Documentation Group: Python 2.4 Status: Open Resolution: None Priority: 5 Submitted By: Raghuram Devarakonda (draghuram) Assigned to: Nobody/Anonymous (nobody) Summary: file to store pickled object should be opened in binary mode Initial Comment: Hi, To unpickle objects on UNIX that were pickled on windows, the file should be opened in binary mode for read and write on windows. It will be nice to have this mentioned in the doc. Something along these lines will be good enough: "Please note that if you are writing the pickled object to a file on windows, make sure it is opened in binary mode. Otherwise, the file may not be able to be used to unpickle on other non-windows platforms". Thanks, Raghu. ---------------------------------------------------------------------- >Comment By: Tim Peters (tim_one) Date: 2006-03-06 14:48 Message: Logged In: YES user_id=31435 Pickle files should be opened in binary mode, regardless of pickle protocol, regardless of platform, and regardless of whether reading or writing. That protocol 0 used to be called "text mode" was an historic mistake, and was given that name by a Unix-head who wouldn't know the difference between text and binary mode if it suck its teeth in their posterior and tore off an entire bloody buttock :-) ---------------------------------------------------------------------- Comment By: Terry J. Reedy (tjreedy) Date: 2006-03-06 14:03 Message: Logged In: YES user_id=593130 Any text file written with /r/n in Windows can have problems when read on *nix or Mac or ???, so this problem is not specific to pickle or even to Python. I am under the impression that the new universal newline support was intended to fix such problems (when used). But as a Win- only user (currently) I have no experience with it. ---------------------------------------------------------------------- Comment By: Raghuram Devarakonda (draghuram) Date: 2006-03-06 10:12 Message: Logged In: YES user_id=984087 There seems to be a mistane in my earlier comment. I meant the unpickling on *UNIX* fails even if ASCII was used on windows. Raghu. ---------------------------------------------------------------------- Comment By: Raghuram Devarakonda (draghuram) Date: 2006-03-06 10:11 Message: Logged In: YES user_id=984087 Hi, The point is that even if ASCII protocol is used on windows(as I was), the unpickling process would fail on windows. So the pickle file should be opened in binary mode on windows even for ASCII protocol. This may make reading the file in notepad difficult but then, cross platform support should take precedence, I suppose. Another option would be for python to do line end translations for ASCII pickle files. Raghu. ---------------------------------------------------------------------- Comment By: Terry J. Reedy (tjreedy) Date: 2006-03-05 22:36 Message: Logged In: YES user_id=593130 For ASCII protocol pickles, intended for human readability, one should use text mode to be able to read the file, for instance, in Notepad. For either binary protocol, I would think binary mode should be best even to reread on Windows. If anything is added, I would put "On Windows, open files in a mode (text/binary) that matches the protocol." at the bottom of http://docs.python.org/lib/node64.html Looking forward to 3.0, when file mode might be more significant (text/binary corresponding to unicode/bytes), the "for windoews' qualifier might be omitted, but this might be premature. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1439659&group_id=5470 _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
