Changes between Initial Version and Version 1 of Ticket #70375, comment 1


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Timestamp:
Jul 14, 2024, 1:01:56 PM (3 months ago)
Author:
RJVB (René Bertin)
Comment:

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  • Ticket #70375, comment 1

    initial v1  
    11You have at least 1 problem here: phonon doesn't seem to have a backend to talk to an actual audio device. For KDE the VLC backend is preferred, but that requires libVLC (which may or may not be available anymore after your changes to the VLC port[s]).
    22
    3 Are you using an X11 version of Qt4, or is there another reason why X11 is getting involved? If the former: I have no idea how it handles X11 errors, but it's possible that it just does an `abort()` whenever one occurs and the application didn't provide its own handler. I started getting crashes like that from GTk applications after a recent upgrade to GTk3 (and apparently sideways related to me running Qt5 apps under X). I patched in an error handler that just prints the message and then continues (into GTk3, so any application that provides its own should still override that). See `XSetIOErrorExitHandler()`.
     3Are you using an X11 version of Qt4, or is there another reason why X11 is getting involved? If the former: I have no idea how it handles X11 errors, but it's possible that it just does an `abort()` whenever one occurs 1) and the application didn't provide its own handler. I started getting crashes like that from GTk applications after a recent upgrade to GTk3 (and apparently sideways related to me running Qt5 apps under X). I patched in an error handler that just prints the message and then continues (into GTk3, so any application that provides its own should still override that). See `XSetIOErrorExitHandler()`.
    44
    55The only thing of the sort that I had to do with Qt5 was to do a regular `exit()` rather than an `abort()` when no `DISPLAY` is defined (and I do get my share of these "failed request" warnings), so it would surprise me a bit if that were different in Qt4.
     6
     71) EDIT: this rambling is of course relevant only if your crash was due to a `SIGABRT`. If not, you could try starting it with `--sync` and run in a debugger with a breakpoint on `_XPrintDefaultError()`. My guess remains that dragon is trying to do something with a window that hasn't been created properly (or has already been destroyed) because of the missing audio backend.
     8
     9https://stackoverflow.com/questions/4456853/need-help-understanding-x11-protocol-errors
     10https://stackoverflow.com/questions/20871304/what-happens-if-you-ignore-a-x11-badwindow-error