Plugin development - old library version keeps being used after recompiling

Nicolás Alvarez nicolas.alvarez at
Sun Jan 17 02:06:54 GMT 2021

El sáb, 16 de ene. de 2021 a la(s) 04:50, David Lerch
(alemariusnexus at escribió:
> Hey,
> I'm starting development of a ThumbCreator-based thumbnailer plugin
> based on kffmpegthumbnailer
> (
> and ffmpegthumbs (, and
> I have managed to get some simple code working in Dolphin.
> The problem is that some part of the system (some kind of KDE service
> cache?) seems to be caching my thumbnailer's shared library because
> when I change its code and recompile, the new changes don't seem to
> come into effect right away. I don't know what triggers it to
> eventually load the new version - it seems to just magically happen
> after a few minutes. Even if I restart Dolphin, disable and re-enable
> the thumbnailer in Dolphin, or run `kbuildsycoca5 --noincremental` -
> it doesn't seem to change anything. It's borderline impossible to
> develop when I can never be sure if it's running the old or the new
> version.
> My current code isn't online anywhere yet, but it's still mostly
> identical to kffmpegthumbnailer if that helps. I simply symlinked the
> .so-file in /usr/lib/x86_64-linux-gnu/qt5/plugins (so it should always
> see the newest version), the .desktop-file for the service in
> /usr/share/kservices5 and the .kcfg-file in /usr/share/config.kcfg.
> Can I maybe force KDE to reload the new library, or something similar?

KIO plugins run in separate processes, not inside Dolphin. There isn't
a "shared library cache", it's just the thumbnailer is still running
in the background.

The process will be shown as something like " [kdeinit5]
thumbnail", as a child process of either kdeinit5, or of Dolphin (if
you used KDE_FORK_SLAVES as Meven suggested). Try "killall".


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