C atexit(), g_atexit -- how to cleanup when a gtk application crashes?

[Stefan Salewski <mail ssalewski de>]

On Wed, 2016-11-30 at 10:41 +0000, Emmanuele Bassi wrote:

https://developer.gnome.org/glib/stable/glib-Miscellaneous-Utility-Functions.html#g-atexit

I have a related problem:

In the last weeks I cleaned up the Nim GTK3 Editor application:

https://github.com/ngtk3/NEd

The primary problem was that I don't cared enough about thread safety
-- I already fixed that following the hints from

https://developer.gnome.org/gdk3/stable/gdk3-Threads.html#gdk-threads-add-idle

One remaining problem is, that I create a second thread and a new
process in the application.

And it would be good if thread and process is terminated when a program
crash of the appication occurs.

Current solution is 

proc cleanup {.noconv.} =
  var msg: StatusMsg
  msg.filepath = nil
  channel.send(msg)
  joinThreads(thread)
  if nsProcess != nil:
    nsProcess.terminate
    discard nsProcess.waitForExit
    nsProcess.close

addQuitProc(cleanup)

which is internally based on C lib atexit() function. Seems to work
fine generally, but problem is the GTK3 process handling:

./ned file1.nim &
./ned file2.nim

file2.nim is send to the primary process, and second process
terminates, as described by

https://wiki.gnome.org/HowDoI/GtkApplication

Unfortunately so the cleanup proc is called already, while the main
application is still running.