Running peel-gen

TL;DR: peel-gen --recursive Gtk 4.0

Most of the C++ code which makes up the peel bindings is not manually written, but gets automatically generated from GIR, the machine-readable XML-based API description format.

The generated bindings are not shipped along with peel. Rather, you should generate bindings yourself. You could generate the bindings once, and then check them into a source control repository. However, we recommend you to instead generate the bindings right at your project’s build time, as a part of your project’s build system if you use one. This way, you get bindings tailored for your specfic environment you’re building in, such as the specific version of GTK that you have, and the system-dependent definitions such as GPid and goffset.

To generate the bindings, you should, first of all, obtain the relevant GIR files for the libraries you’re going to use; for example, the file describing GTK 4 is named Gtk-4.0.gir. Typically, on a Linux distribution, these files are part of the relevant development packages, along with the C headers. For instance, the GIR file for GTK is contained in the libgtk-4-dev package on Debian, and in the gtk4-devel package on Fedora. Typically, system-wide GIR files are installed into /usr/share/gir-1.0/.

Secondly, you need the peel-gen executable, which is the peel bindings generator. It is implemented in Python 3 with no external dependencies (same as Meson). It can be run directly from the peel source repository (peel-gen.py, this is known as running peel-gen “uninstalled”), or as peel-gen command if peel is installed.