Re: [Denemo-devel] Denemo sometimes hangs (crashes) on quit

[Richard Shann]

On Tue, 2015-10-27 at 10:21 +0100, Andreas Schneider wrote:
> Am 27.10.2015 um 09:44 schrieb Richard Shann:
> >> Yes, this is with MIDI hardware attached (my master keyboard), and I'm
> >> using the latest git version (I do not know how to swtich to the release
> >> candidate in git).
> > well, no need at the moment as they are the same - we are in code freeze
> > now for the release.
> >>  It returned to the (gdb) prompt (that is, the prompt
> >> appeared when pressing the return key as many text was in the console
> >> before). 
> > This returning to the prompt when pressing the Return key is something I
> > also see quite often, I've not been sure that it is an indicator of a
> > crash during the termination of the Denemo process, I think perhaps not,
> > as that should be accompanied by a message from GDB about the signal
> > received (e.g. SEGFAULT ...).

I see this hanging thing too quite often. I just experimented with
pressing Ctrl-C instead of the Return key, and sure enough, it is
hanging waiting for a read from stdin. This is happening during the call
to portmidi_destroy(). So my guess is this is one of those situations
where the library code is asking the user to press enter before
returning. There is one that we looked at before - I don't recall which
library, but it goes to great efforts to make sure that it doesn't quit
without this wait - that one puts out Press Enter... to stdout before
waiting for input. There is nothing to be seen in this case so perhaps
this is a different one, or is some other sort of trap.
I'll experiment with not calling portmidi_destroy() just exiting, I'm
not sure what the consequences might be...

Richard