Revision control
Copy as Markdown
// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
/*!
\page qt-conf.html
\title Using qt.conf
\target qt.conf
You can use the \c qt.conf file to override QLibraryInfo paths,
or to specify arguments to be passed to the platform plugins.
\section1 Format and Location
The \c qt.conf file is an INI text file, as described in the
\l {QSettings::Format}{QSettings} documentation.
QLibraryInfo will load \c qt.conf from one of the following locations:
\list 1
\li \c :/qt/etc/qt.conf using the resource system
\li on Apple platforms, in the Resource directory inside the application
bundle, for example \c assistant.app/Contents/Resources/qt.conf on \macos.
\li in the directory containing the application executable, i.e.
QCoreApplication::applicationDirPath() + QDir::separator() + "qt.conf"
\endlist
\section1 Overriding Paths
The \c qt.conf file can be used to override the default paths used by Qt.
These paths are accessible using the QLibraryInfo class.
Without \c qt.conf, the Qt libraries will use the default paths
to look for plugins, translations, and so on. These paths may not
exist on the target system, or they may not be
accessible. Because of this, you may need \c qt.conf to make the Qt
libraries look elsewhere.
The file should have
a \c Paths group with one or more entries that correspond to
values of the QLibraryInfo::LibraryLocation enum. See the
QLibraryInfo documentation for details on the meaning of the
various locations.
\table
\header \li Entry \li Default Value
\row \li \c Prefix \li \l QCoreApplication::applicationDirPath()
\row \li \c Documentation \li \c doc
\row \li \c Headers \li \c include
\row \li \c Libraries \li \c lib
\row \li \c LibraryExecutables \li \c libexec on Unix, \c bin on Windows
\row \li \c Binaries \li \c bin
\row \li \c Plugins \li \c plugins
\row \li \c QmlImports \li \c qml
\row \li \c ArchData \li \c .
\row \li \c Data \li \c .
\row \li \c Translations \li \c translations
\row \li \c Examples \li \c examples
\row \li \c Tests \li \c tests
\row \li \c Settings \li \c .
\endtable
Absolute paths are used as specified in the \c qt.conf file. All
paths are relative to the \c Prefix. On Windows and Linux, the \c
Prefix is relative to the directory containing the application
executable (QCoreApplication::applicationDirPath()). On \macos,
the \c Prefix is relative to the \c Contents in the application
bundle. For example, \c application.app/Contents/PlugIns/ is the
default location for loading Qt plugins. Note that the plugins
need to be placed in specific sub-directories under the
\c{plugins} directory (see \l{How to Create Qt Plugins} for
details).
\note For backwards-compatibility, the entry \c Qml2Imports is valid in the
\c{Paths} section and is treated as fallback for \c{QmlImports}.
For example, a \c qt.conf file could contain the following:
\snippet snippets/code/doc_src_qt-conf.qdoc 0
\note The backslash character is treated as a special character
in INI files (see QSettings). It is therefore recommended to
use forward slashes for paths on Windows as well. Otherwise,
an escape character is required:
\code
Prefix = c:\\SomePath
\endcode
Since Qt 6.8, it is possible to provide more than one path per entry.
They have to be provided as a comma separated list. For example
\code
QmlImports = "/path/to/imports1","/path/to/imports2"
\endcode
It is possible to add spaces before and after the comma. It is also
possible to omit the quotes around entries if path do not contain
commas or spaces.
\section1 Configuring Arguments to the Platform Plugins
The \c qt.conf may contain a \c Platforms group, whose keys are
comma-delimited lists of arguments to be passed to the platform
plugin. The key name is the name of the platform plugin with the
first letter upper-cased followed by \c Arguments.
For example:
\snippet snippets/code/doc_src_qt-conf.qdoc 1
would cause the Windows platform plugin to use the FreeType font engine.
\section1 How to deal with parallel installations of older Qt versions
For environments that require an installation of an earlier major
version of Qt as well, it is possible to use a version-specific
qt.conf. This is often necessary in transition phases from one Qt
version to the next, or to avoid conflicts caused by an existing
file without version.
For this purpose, a file named \tt qt\qtmajorversion.conf can be
used instead of the \c qt.conf file. If both files exist in the
directory described above, \tt qt\qtmajorversion.conf is used.
*/