Bugs item #1102649, was opened at 2005-01-14 22:58 Message generated for change (Settings changed) made by birkenfeld You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1102649&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: John Machin (sjmachin) >Assigned to: Reinhold Birkenfeld (birkenfeld) Summary: pickle files should be opened in binary mode Initial Comment: pickle (and cPickle): At _each_ mention of the pickle file, the docs should say that it should be opened with 'wb' or 'rb' mode as appropriate, so that a pickle written on one OS can be read reliably on another. The example code at the end of the section should be updated to use the 'b' flag. ---------------------------------------------------------------------- Comment By: Martin v. Löwis (loewis) Date: 2005-02-24 21:08 Message: Logged In: YES user_id=21627 sjmachin, it seems pretty clear what to do now. Would you volunteer to come up with a patch yourself? ---------------------------------------------------------------------- Comment By: John Machin (sjmachin) Date: 2005-01-19 14:51 Message: Logged In: YES user_id=480138 Re Fred's question: Refer to thread starting at http://mail.python.org/pipermail/python-dev/2003- February/033362.html Looks like the story is like this: For pickle mode 1 or higher, always use binary mode for reading/writing. For pickle mode 0, either (a) read/write in text mode and if moving to another OS, do so in text mode i.e. convert the line endings where necessary or (b) as for pickle mode 1+, stick with binary throughout. Also should add a generalisation of Tim's comment re NotePad, e.g. something like """A file written with pickle mode 0 and file mode 'wb' will contain lone linefeeds as line terminators. This will cause it to "look funny" when viewed on Windows or MacOS as a text file by editors like Notepad that do not understand this format.""" ---------------------------------------------------------------------- Comment By: Tim Peters (tim_one) Date: 2005-01-19 14:45 Message: Logged In: YES user_id=31435 Yes, binary mode should always be used, regardless of protocol. Else pickles aren't portable across boxes (in particular, Unix can't read a protocol 0 pickle produced on Windows if the latter was written to a text-mode file). "text mode" was a horrible name for protocol 0. ---------------------------------------------------------------------- Comment By: Fred L. Drake, Jr. (fdrake) Date: 2005-01-19 06:09 Message: Logged In: YES user_id=3066 In response to irmin's comment: freopen() is only an option for real file objects; pickles are often stored or read from other sources. These other sources are usually binary to begin with, fortunately, though this issue probably deserves some real coverage in the documentation either way. ---------------------------------------------------------------------- Comment By: Fred L. Drake, Jr. (fdrake) Date: 2005-01-19 06:06 Message: Logged In: YES user_id=3066 Is this true in all cases? Shouldn't files containing text pickles (protocol 0) be opened in text mode? (A problem, given that all protocols should be readable without prior knowledge of the protocol used to write the pickle.) ---------------------------------------------------------------------- Comment By: Irmen de Jong (irmen) Date: 2005-01-16 16:07 Message: Logged In: YES user_id=129426 Can't the pickle code just freopen() the file itself, using binary mode? Or is this against Python's rule "explicit is better than implicit" ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1102649&group_id=5470 _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
