How Does One Create A Gtk+ Application?

How does one go about creating a gtk+ working application? Is it even possible?

Seriously.

TL;DR: The Gtk+ ABI is broken so often that distribution-supplied binaries rarely work.

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Imagine it is the time when Gtk+ 3.0 was released. You have a beautiful application with no bugs. For the sake of argument. Distributions ship it pre-compiled and life is good.

Then distributions update Gtk+ and everything based on GtkGrid breaks. You work around that in your source code, but distributions do not release new versions of your program until its next release.

In the meantime, Gtk+ breaks ABI compatibility for mouse wheel scrolling. Distributions update that and your program ceases to work with mouse wheels. You work around that in your source code, but distributions do not release new versions of your program until its next release.

In the meantime, Gtk+ breaks ABI compatibility of scrolled windows. Windows that used to have sane sizes now have near-zero size and when distributions update Gtk+, users of your application are not impressed. You work around that in your source code, but distributions do not release new versions of your program until its next release.

In the meantime, Gtk+ breaks ABI compatibility of redrawing. Parts of the gui that used to render correctly now stops updating at all. When distributions update Gtk+, your program ceases to work. You work around that in your source code, but distributions do not release new versions of your program until its next release.

Somewhere in the middle of this, Ubuntu decides to break scrollbars using a Gtk+ plugin. Your first hint that this has happened is when Ubuntu users start filing bug reports.

In the meantime, the layout rules for GtkGrid change again. When distributions update Gtk+, your program looks awful. You work around that in your source code, but distributions do not release new versions of your program until its next release.

Your program works with multiple screens. Or rather, it used to work with multiple screens. Then Gtk+ dropped support for it without notice.

Now I hear we are in for another round of breaking rendering because of some Wayland deficiency. It sounds like something that will require a runtime version check to deal with. In the meantime, if any distribution ships with updated Gtk+ but without your program updated, well, things will be broken.

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The sum of all the above is that your application will have serious issues for anyone using the distribution supplied binary. And it is not because of anything you did wrong!

How does one shield oneself from this, i.e., how does one ensure that the binary compiled (say) three years (or months) ago continues to work reasonably? I don’t know. As far as I know, Gtk+ does not support parallel installations of 3.0, 3.2, …; if Gtk+ does support it, then none of the distributions do it. I’m sure it would be painful. Note, that using static copies of Gtk+ is not a viable solution because the binaries are created by distributions. They really have no way of knowing what Gtk+ version to use for any given application and they probably would not like to deal with the security implications of static linking.

(Note: the time ordering of the above is probably off here and there. There are probably also more ABI breaks that I do not remember right now.)

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