Added Area-Library, Library-Isolate, Triaged labels.

Removed Type-Defect label.
Added Type-Enhancement label.

This comment was originally written by @kaendfinger

This can be marked as fixed I think, because we can add hooks for SIGTERM.

This comment was originally written by @zoechi

Does this work on all platforms?
I haven't used it myself but there were complaints in the forum after this was implemented (several months ago though) that there is no single hook that works on all platforms.

This comment was originally written by googlegroups...@kaioa.com

According to the docs, most of those process signals are not available on Windows:

https://api.dartlang.org/apidocs/channels/stable/dartdoc-viewer/dart-io.ProcessSignal#id_watch

I just tried it myself. This example works with Linux, but not with Windows:

    import 'dart:io';
    
    void main() {
      ProcessSignal.SIGTERM.watch().listen((_) {
        print('SIGTERM');
      });
    }

On Windows, it bombs with:

    Uncaught Error: SignalException: Failed to listen for SIGTERM

Note: calling exit(0) does not call SIGTERM listeners. I think that this decision should be re-evaluated.

This comment was originally written by @kaendfinger

Whatever node does to fake SIGTERM or something for it's exit listener, that's what we need to do.

This could be solved by an exit-callback for the current isolate: #21999

We now have addOnExitListener
https://api.dartlang.org/stable/2.0.0/dart-isolate/Isolate/addOnExitListener.html