Re: [Discuss-gnuradio] QT Throw Bad Alloc on flowgraph startup

[Christoph Mayer]

This may be related to https://github.com/gnuradio/gnuradio/issues/2407

Best regards
Christoph

On Fri, Apr 26, 2019 at 6:42 PM Marcus Müller (GNU Radio maintainer)
<address@hidden> wrote:
>
> Hi Tom,
>
> shoot, that sounds like we half-fixed a bug :(
> How proficient are you with GDB? Could you get a backtrace? (maybe
> based on [1]?)
> Thank you!
> Marcus
>
> [1] https://wiki.gnuradio.org/index.php/TutorialsGDB
>
> On Fri, 2019-04-26 at 09:25 -0700, Tom McDermott wrote:
> >
> > I've had this problem intermittently for about a year.  On starting
> > the flowgraph it will terminate
> > with QT Throw : Bad Alloc.   Building different versions from about
> > 3.7.10 ish to 3.7.latest will change
> > whether or not it happens 100% of the time or 30% of the time.
> >
> > Today, I noticed that disabling the QT Frequency sink causes it to
> > not throw, and the flowgraph runs
> > fine.  One input to QT Freq Sink works OK many times, two inputs
> > causes it to throw virtually every
> > time.
> >
> > After some playing around:
> > If I change the initial QT Frequency sink to start with a much
> > smaller FFT size (256), then it does not
> > QT Throw on startup even with two channels.  The original
> > configuration was to start at FFT size of 1024
> > (causing throw).  Setting the block to start with FFT size of 256
> > causes it not to throw.
> >
> > When the flowgraph starts, the QT Frequency sink does not display any
> > signals.  If, while running
> > in GRC, I change the FFT size then suddenly the signal traces start
> > displaying.  Also while running
> > I can then change the FFT size, and it keeps running, and the display
> > shows the effect of changing
> > the resolution.
> >
> > So I think the QT Throw problem has something to do with the starting
> > FFT size, and the non-display
> > seems to fix itself after changing the FFT size all related to QT
> > Frequency Sink.
> >
> > Ubuntu 16.04,  with gnuradio / GRC  3.7.13.5
> >
> > -- Tom, N5EG
> >
> >
> >
> > _______________________________________________
> > Discuss-gnuradio mailing list
> > address@hidden
> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
>
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio