) is the official C interface for the popular GUI library GTK .
gtkmm is free software distributed under the GNU Lesser General Public License (LGPL).
The X Window System, also known as X11, is probably the most well known.
We will develop a threaded worker class, a trivial once, otherwise it will abort with an error.
This has the additional perk of aborting the program if threads are not supported at all.
If the rest of this function doesn’t make sense to you, walk away from this tutorial and go read the Gtkmm one.
This is by design: all gtk events (including window refreshing and updates) are handled in the mainloop, and while your application or callback code is running the mainloop can't handle window update events.
Therefore nothing will happen in the application windows.
If our drawing application is going to take a long time (longer than 1/30th of a second) then simply launching a new drawing thread every time the timer executes could result in a pile-up of threads and a lot of memory badness.