gtk  4.3.1
About: GTK (the GIMP Toolkit; version 4; formerly GTK+) is a library for creating graphical user interfaces for the X Window System. Unstable release.
  Fossies Dox: gtk-4.3.1.tar.xz  ("unofficial" and yet experimental doxygen-generated source code documentation)  

gtk Documentation

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GTK — The GTK toolkit

Build status

General information

GTK is a multi-platform toolkit for creating graphical user interfaces. Offering a complete set of widgets, GTK is suitable for projects ranging from small one-off projects to complete application suites.

GTK is free software and part of the GNU Project. However, the licensing terms for GTK, the GNU LGPL, allow it to be used by all developers, including those developing proprietary software, without any license fees or royalties.

The official download location

The official web site

The official developers blog

Discussion forum

Nightly documentation can be found at

Nightly flatpaks of our demos can be installed from the GNOME Nightly repository:

  • flatpak remote-add --if-not-exists gnome-nightly
  • flatpak install gnome-nightly org.gtk.Demo4
  • flatpak install gnome-nightly org.gtk.WidgetFactory4
  • flatpak install gnome-nightly org.gtk.IconBrowser4

Building and installing

In order to build GTK you will need:

You will also need various dependencies, based on the platform you are building for:

If you are building the X11 backend, you will also need:

  • Xlib, and the following X extensions:
    • xrandr
    • xrender
    • xi
    • xext
    • xfixes
    • xcursor
    • xdamage
    • xcomposite

If you are building the Wayland backend, you will also need:

  • Wayland-client
  • Wayland-protocols
  • Wayland-cursor
  • Wayland-EGL

Once you have all the necessary dependencies, you can build GTK by using Meson:

$ meson _build .
$ cd _build
$ ninja

You can run the test suite using:

$ meson test

And, finally, you can install GTK using:

$ sudo ninja install

Complete information about installing GTK and related libraries can be found in the file:


Or online

How to report bugs

Bugs should be reported on the issues page.

In the bug report please include:

  • Information about your system. For instance:

    • which version of GTK you are using
    • what operating system and version
    • for Linux, which distribution
    • if you built GTK, the list of options used to configure the build

    And anything else you think is relevant.

  • How to reproduce the bug.

    If you can reproduce it with one of the demo applications that are built in the demos/ subdirectory, on one of the test programs that are built in the tests/ subdirectory, that will be most convenient. Otherwise, please include a short test program that exhibits the behavior. As a last resort, you can also provide a pointer to a larger piece of software that can be downloaded.

  • If the bug was a crash, the exact text that was printed out when the crash occurred.

  • Further information such as stack traces may be useful, but is not necessary.

Contributing to GTK

Please, follow the contribution guide to know how to start contributing to GTK.

Release notes

The release notes for GTK are part of the migration guide in the API reference. See:

Licensing terms

GTK is released under the terms of the GNU Lesser General Public License, version 2.1 or, at your option, any later version, as published by the Free Software Foundation.

Please, see the COPYING file for further information.

GTK includes a small number of source files under the Apache license:

  • A fork of the roaring bitmaps implementation in gtk/roaring
  • An adaptation of timsort from python in gtk/timsort