qt.conf file overrides the hard-coded paths that are compiled into the Qt library. These paths are accessible using the QLibraryInfo class. Without
qt.conf, the functions in QLibraryInfo return these hard-coded paths; otherwise they return the paths as specified in
qt.conf, the Qt libraries will use the hard-coded paths to look for plugins, translations, and so on. These paths may not exist on the target system, or they may not be accesssible. Because of this, you need
qt.conf to make the Qt libraries look elsewhere.
QLibraryInfo will load
qt.conf from one of the following locations:
:/qt/etc/qt.confusing the resource system
- on Mac OS X, in the Resource directory inside the application bundle, for example
- in the directory containing the application executable, i.e. QCoreApplication::applicationDirPath() + QDir::separator() + "qt.conf"
qt.conf file is an INI text file, as described in the QSettings documentation. The file should have a
Paths group which contains the entries that correspond to each value of the QLibraryInfo::LibraryLocation enum. See the QLibraryInfo documentation for details on the meaning of the various locations.
Absolute paths are used as specified in the
qt.conf file. All paths are relative to the
Prefix. On Windows and X11, the
Prefix is relative to the directory containing the application executable (QCoreApplication::applicationDirPath()). On Mac OS X, the
Prefix is relative to the
Contents in the application bundle. For example,
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
plugins directory (see How to Create Qt Plugins for details).
For example, a
qt.conf file could contain the following:
[Paths] Prefix = /some/path Translations = i18n
Subgroups of the
Paths group may be used to specify locations for specific versions of the Qt libraries. Such subgroups are of the form
Paths/x.y.z, where x is the major version of the Qt libraries, y the minor, and z the patch level. The subgroup that most closely matches the current Qt version is used. If no subgroup matches, the
Paths group is used as the fallback. The minor and patch level values may be omitted, in which case they default to zero.
For example, given the following groups:
Paths Paths/4 Paths/4.1 Paths/4.2.5 Paths/6
The current version will be matched as shown:
- 4.0.1 matches
- 4.1.5 matches
- 4.6.3 matches
Paths/4.2.5(because 4.2.5 is the latest version with the same major version number)
- 5.0.0 matches
- 6.0.2 matches
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