source: introduction/important/locale-issues.xml@ c151abf

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<sect1 id="locale-issues" xreflabel="Locale Related Issues">
  <?dbhtml filename="locale-issues.html"?>

  <sect1info>
    <othername>$LastChangedBy$</othername>
    <date>$Date$</date>
  </sect1info>

  <title>Locale Related Issues</title>

  <para>This page contains information about locale related problems and
  issues. In this paragraph you'll find a generic overview of things that can
  come up when configuring your system for various locales. The previous
  sentence and the remainder of this paragraph must still be
  revised/completed.</para>

 <sect2>

    <title>Package Specific Locale Issues</title> 

    <para>For package specific issues, find the concerned package from the list
    below and follow the link to view the available information. If a package
    is not listed here, it means there are no known locale specific issues or
    problems with that package.</para>

    <itemizedlist>

      <title>List of Packages with Locale Related Issues</title>

      <listitem>
        <para><xref linkend="locale-mc"/></para>
      </listitem>
      <listitem>
        <para><xref linkend="locale-unzip"/></para>
      </listitem>

    </itemizedlist>

    <sect3 id="locale-mc" xreflabel="MC-&mc-version;">

      <title><xref linkend="mc"/></title>

      <para>This package makes the assumption that <quote>characters</quote>
      and <quote>bytes</quote> are the same thing. This is not true in UTF-8
      based locales. Due to this assumption <application>MC</application> will
      incorrectly position characters on the screen. After the cursor is moved
      a bit the screen becomes totally unreadable, as illustrated on
      <ulink url="http://anduin.linuxfromscratch.org/files/BLFS/mc-bad.png">this
      screenshot</ulink> (taken in a ru_RU.UTF-8 locale). Additionally, input
      of non-ASCII characters in the editor is impossible, even after selecting
      <quote>Other 8-bit</quote> encoding from the menu.</para>

    </sect3>

    <sect3 id="locale-unzip" xreflabel="UnZip-&unzip-version;">

      <title><xref linkend="unzip"/></title>

      <note>
        <para>Use of <application>UnZip</application> in the
        <application>JDK</application>, <application>Mozilla</application>,
        <application>DocBook</application> or any other BLFS package
        installation is not a problem, as BLFS instructions never use
        <application>UnZip</application> to extract a file with non-ASCII
        characters in the file's name.</para>
      </note>

      <para>The <application>UnZip</application> package assumes that filenames
      stored in the ZIP archives created on non-Unix systems are encoded in
      CP850, and that they should be converted to ISO-8859-1 when writing files
      onto the filesystem. Such assumptions are not always valid. In fact,
      inside the ZIP archive, filenames are encoded in the DOS codepage that is
      in use in the relevant country, and the filenames on disk should be in
      the locale encoding. In MS Windows, the OemToChar() C function (from
      <filename>User32.DLL</filename>) does the correct conversion (which is
      indeed the conversion from CP850 to a superset of ISO-8859-1 if MS
      Windows is set up to use the US English language), but there is no
      equivalent in Linux.</para>

      <para>When using <command>unzip</command> to unpack a ZIP archive
      containing non-ASCII filenames, the filenames are damaged because
      <command>unzip</command> uses improper conversion when any of its
      encoding assumptions are incorrect. For example, in the ru_RU.KOI8-R
      locale, conversion of filenames from CP866 to KOI8-R is required, but
      conversion from CP850 to ISO-8859-1 is done, which produces filenames
      consisting of undecipherable characters instead of words (the closest
      equivalent understandable example for English-only users is rot13). There
      are several ways around this limitation:</para>

      <para>1) For unpacking ZIP archives with filenames containing non-ASCII
      characters, use <ulink url="http://www.winzip.com/">WinZip</ulink> while
      running the <ulink url="http://www.winehq.com/">Wine</ulink> Windows
      emulator.</para>

      <para>2) After running <command>unzip</command>, fix the damage made to
      the filenames using the <command>convmv</command> tool
      (<ulink url="http://j3e.de/linux/convmv/"/>). The following is an example
      for the ru_RU.KOI8-R locale:</para>

      <blockquote>
        <para>Step 1. Undo the conversion done by
        <command>unzip</command>:</para>

<screen><userinput>convmv -f iso-8859-1 -t cp850 -r --nosmart --notest \
    <replaceable>[/path/to/unzipped/files]</replaceable></userinput></screen>

        <para>Step 2. Do the correct conversion instead:</para>

<screen><userinput>convmv -f cp866 -t koi8-r -r --nosmart --notest \
    <replaceable>[/path/to/unzipped/files]</replaceable></userinput></screen>
      </blockquote>

      <para>3) Apply this patch to unzip:
      <ulink url="https://bugzilla.altlinux.ru/attachment.cgi?id=532"/></para>

      <para>It allows to specify the assumed filename encoding in the ZIP
      archive using the <option>-O charset_name</option> option and the
      on-disk filename encoding using the <option>-I charset_name</option>
      option. Defaults: the on-disk filename encoding is the locale encoding,
      the encoding inside the ZIP archive is guessed according to the builtin
      table based on the locale encoding. For US English users, this still
      means that unzip converts from CP850 to ISO-8859-1 by default.</para>

      <para>Caveat: this method works only with 8-bit locale encodings, not
      with UTF-8. Attempting to use a patched <command>unzip</command> in UTF-8
      locales may result in a segmentation fault and is probably a security
      risk.</para>

    </sect3>

  </sect2>

</sect1>