## Compiling the GTK+ libraries Compiling the GTK+ Libraries — How to compile GTK+ itself |

## Building GTK+ on UNIX-like systems

This chapter covers building and installing GTK+ on UNIX and UNIX-like systems such as Linux. Compiling GTK+ on Microsoft Windows is different in detail and somewhat more difficult to get going since the necessary tools aren't included with the operating system.

Before we get into the details of how to compile GTK+, we should mention that in many cases, binary packages of GTK+ prebuilt for your operating system will be available, either from your operating system vendor or from independent sources. If such a set of packages is available, installing it will get you programming with GTK+ much faster than building it yourself. In fact, you may well already have GTK+ installed on your system already.

On all supported platforms, GTK+ uses the Meson build system.

          tar xvfJ gtk+-3.24.0.tar.xz

Once you have extracted the files from the release archive, and you entered the source directory, you can use the meson command to configure the project.

          meson setup --prefix=/opt/gtk _builddir .

A full list of options can be found by running meson configure from within the build directory. In general, the defaults are right and should be trusted.

After you've run meson setup, you then run the meson compile command to build the project and install it.

          meson compile -C _builddir
          meson install -C _builddir

If you don't have permission to write to the directory you are installing in, you may have to change to root temporarily before running meson install.

Several environment variables are useful to pass to set before running configure. `CPPFLAGS` contains options to pass to the C compiler, and is used to tell the compiler where to look for include files. The `LDFLAGS` variable is used in a similar fashion for the linker. Finally the `PKG_CONFIG_PATH` environment variable contains a search path that pkg-config (see below) uses when looking for files describing how to compile programs using different libraries. If you were installing GTK+ and it's dependencies into `/opt/gtk`, you might want to set these variables as:

          CPPFLAGS="-I/opt/gtk/include"
          LDFLAGS="-L/opt/gtk/lib"
          PKG_CONFIG_PATH="/opt/gtk/lib/pkgconfig"
          export CPPFLAGS LDFLAGS PKG_CONFIG_PATH

You may also need to set the `LD_LIBRARY_PATH` environment variable so the systems dynamic linker can find the newly installed libraries, and the `PATH` environment program so that utility binaries installed by the various libraries will be found.

          LD_LIBRARY_PATH="/opt/gtk/lib"
          PATH="/opt/gtk/bin:$PATH"
          export LD_LIBRARY_PATH PATH

## Dependencies

Before you can compile the GTK+ widget toolkit, you need to have various other tools and libraries installed on your system. The main tool needed during the build process (as differentiated from the tools used in when creating GTK+ mentioned above such as meson) is pkg-config.

- pkg-config is a tool for tracking the compilation flags needed for libraries that are used by the GTK+ libraries. (For each library, a small `.pc` text file is installed in a standard location that contains the compilation flags needed for that library along with version number information.)

Some of the libraries that GTK+ depends on are maintained by by the GTK+ team: GLib, GdkPixbuf, Pango, ATK and GObject Introspection. Other libraries are maintained separately.

- The GLib library provides core non-graphical functionality such as high level data types, Unicode manipulation, and an object and type system to C programs. It is available here.

- The GdkPixbuf library provides facilities for loading images in a variety of file formats. It is available here.

- Pango is a library for internationalized text handling. It is available here.

- ATK is the Accessibility Toolkit. It provides a set of generic interfaces allowing accessibility technologies such as screen readers to interact with a graphical user interface. It is available here.

- Gobject Introspection is a framework for making introspection data available to language bindings. It is available here.

External dependencies

- The GNU libiconv library is needed to build GLib if your system doesn't have the `iconv()` function for doing conversion between character encodings. Most modern systems should have `iconv()`.

- The libintl library from the GNU gettext package is needed if your system doesn't have the `gettext()` functionality for handling message translation databases.

- The libraries from the X window system are needed to build Pango and GTK+. You should already have these installed on your system, but it's possible that you'll need to install the development environment for these libraries that your operating system vendor provides.

- The fontconfig library provides Pango with a standard way of locating fonts and matching them against font names.

- Cairo is a graphics library that supports vector graphics and image compositing. Both Pango and GTK+ use cairo for all of their drawing.

- libepoxy is a library that abstracts the differences between different OpenGL libraries. GTK+ uses it for cross-platform GL support.

- The Wayland libraries are needed to build GTK+ with the Wayland backend.

- The shared-mime-info package is not a hard dependency of GTK+, but it contains definitions for mime types that are used by GIO and, indirectly, by GTK+. gdk-pixbuf will use GIO for mime type detection if possible. For this to work, shared-mime-info needs to be installed and `XDG_DATA_DIRS` set accordingly at configure time. Otherwise, gdk-pixbuf falls back to its built-in mime type detection.

## Building and testing GTK+

First make sure that you have the necessary external dependencies installed: pkg-config, GNU make, the JPEG, PNG, and TIFF libraries, FreeType, and, if necessary, libiconv and libintl. To get detailed information about building these packages, see the documentation provided with the individual packages. On a Linux system, it's quite likely you'll have all of these installed already except for pkg-config.

Then build and install the GTK+ libraries in the order: GLib, Pango, ATK, then GTK+. For each library, follow the steps of `configure`, `make`, `make install` mentioned above. If you're lucky, this will all go smoothly, and you'll be ready to start compiling your own GTK+ applications. You can test your GTK+ installation by running the gtk3-demo program that GTK+ installs.

If either the meson setup or the meson compile commands fail, look closely at the error messages printed; these will often provide useful information as to what went wrong.

## Extra Configuration Options

In addition to the standard meson options when configuring the GTK+ project, you have a number of additional arguments. (Command line arguments for the other libraries are described in the documentation distributed with the those libraries.)

`meson setup`
[ -Dxinerama=[yes/no/auto] ]
[ -Dgtk_doc=[false/true] ]
[ -Dprint_backends=["cups,file,lpr,papi,test,auto"] ]
[ -Dx11_backend=[false/true] ]
[ -Dwin32_backend=[false/true] ]
[ -Dquartz_backend=[false/true] ]
[ -Dbroadway_backend=[false/true] ]
[ -Dwayland_backend=[false/true] ]
[ -Dintrospection=[false/true] ]
[ -Dinstalled_tests=[false/true] ]

`-Dxinerama`. By default GTK will try to link against the Xinerama libraries if they are found. This option can be used to explicitly control whether Xinerama should be used.

`-Dgtk_doc`. The gtk-doc package is used to generate the reference documentation included with GTK+. By default support for gtk-doc is disabled because it requires various extra dependencies to be installed. If you have gtk-doc installed and are modifying GTK+, you may want to enable gtk-doc support by passing in `-Dgtk_doc=true`. If not enabled, pre-generated HTML files distributed with GTK+ will be installed.

`-Dprint_backends`. By default GTK will try to build the appropriate print backend for the system. You can specify the print backends manually to explicitly control which backends should be build.

`-Dx11_backend`, `-Dwin32_backend`, `-Dquartz_backend`, `-Dbroadway_backend`, `-Dwayland_backend`. Enable specific backends for GDK. If none of these options are given, the x11 backend will be enabled by default, unless the platform is Windows, in which case the default is win32. If any backend is explicitly enabled or disabled, no other platform will be enabled automatically. Other supported backends are the quartz backend for macOS, and the HTML-based Broadway backend.

`-Dintrospection`. Build with or without introspection support. The default is 'true'.

`-Dinstalled-tests`. Whether to install tests on the system. If enabled, tests and their data are installed in `${libexecdir}/gtk+/installed-tests`. Metadata for the tests is installed in `${prefix}/share/installed-tests/gtk+`. To run the installed tests, gnome-desktop-testing-runner can be used.