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Add corrections for some paths (e.g. man pages) Tags git-svn-id: svn://svn.linuxfromscratch.org/BLFS/trunk/BOOK@12783 af4574ff-66df-0310-9fd7-8a98e5e911e0
65 lines
3.3 KiB
XML
65 lines
3.3 KiB
XML
<?xml version="1.0" encoding="ISO-8859-1"?>
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<!DOCTYPE note PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
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<!ENTITY % general-entities SYSTEM "../general.ent">
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%general-entities;
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]>
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<!-- $LastChangedBy: $
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$Date: $ -->
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<sect2>
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<title>Qt Installation Alternatives</title>
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<para>The installation of <application>Qt</application> presents
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several challenges and choices. Complicating the Qt installation is the fact
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that there are two versions, <application>Qt4</application> and
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<application>Qt5</application>, that have executable programs with
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identical names. If both packages are installed on one system,
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the only methods to manage which set of programs is used is to
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either control the users' <envar>PATH</envar> or to rename files
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either directly or via symbolic links. Both packages cannot
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be installed in the same directory.
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</para>
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<para>If you are only going to install one of the Qt versions,
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the choice of installation methods is easier. You can either
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install the components in the several directories of the <filename
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class='directory'>/usr</filename> hierarchy or install the
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entire package in a separate directory of your choice. We
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refer to these options below as "Method 1: Installing in /usr"
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and "Method 2: Installing in /opt".</para>
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<para>If both versions of Qt are to be installed, one or both versions need
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to be installed in a separate directory. For the purposes here we use the
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<filename class='directory'>/opt</filename> directory. The selection of
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which version is being used by individual users on a system is controlled
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by the <envar>PATH</envar> variable. Other systems can be designed, but
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the BLFS editors find the <envar>PATH</envar> method easiest.</para>
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<para> The advantage of installing in <filename
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class='directory'>/usr</filename> is that no updates to the
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<filename>/etc/ld.so.conf</filename> or
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<filename>/etc/man_db.conf</filename> files are required. The package files
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are distributed within several subdirectories of the <filename
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class='directory'>/usr</filename> hierarchy. This is the method that most
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commercial distributions use. The disadvantage for BLFS users is that this
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Qt instance cannot be upgraded while it is in use. For instance, it cannot
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be upgraded from a running KDE environment. It also precludes having
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multiple versions of Qt on your system and does not allow reverting to
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an existing, known working instance of Qt.</para>
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<para> The advantage of installing <application>Qt</application> in a
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custom directory such as
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<filename class='directory'>/opt/qt-&qt4-version;</filename> or
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<filename class='directory'>/opt/qt-&qt5-version;</filename> or
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is that it keeps all the
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package files consolidated in a dedicated directory hierarchy. By using
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this method, an update can be made without overwriting a previous
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installation and users can easily revert to a previous version by changing
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one symbolic link or merely changing the PATH variable. It also allows a
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developer to maintain multiple versions of <application>Qt4</application>
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or <application>Qt5</application> for testing. </para>
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</sect2>
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