[Interest] Destructor appearing twice in the stack trace?

[Gian Maxera]

Are you sure that in some way it’s not child of itself ?
Qt automatically destroy all children of an QObject … and I really don’t know how safe is Qt to assign itself as child.

Ciao,
Gianluca.


> On 9 Nov 2015, at 15:55, Etienne Sandré-Chardonnal <etienne.sandre at m4x.org> wrote:
> 
> Dear Gian,
> 
> I have checked that of course. But this is not the case, the destructor has been reduced to a single call to qDebug (see my other mail) and the error persists.
> Also, when I set a breakpoint on the qDebug line, the debugger halts on the second call (both are already in the stack) which is again very suprising.
> 
> I use the debugger often and never had any problem like that before.
> 
> Cheers,
> 
> Etienne
> 
> 
> 
> 2015-11-09 16:43 GMT+01:00 Gian Maxera <gmaxera at gmail.com <mailto:gmaxera at gmail.com>>:
> 
> > On 9 Nov 2015, at 15:38, Konstantin Tokarev <annulen at yandex.ru <mailto:annulen at yandex.ru>> wrote:
> >
> >
> >
> > 09.11.2015, 18:22, "Etienne Sandré-Chardonnal" <etienne.sandre at m4x.org <mailto:etienne.sandre at m4x.org>>:
> >> Dear all,
> >>
> >> I am debugging an app which crashes when an object is being deleted. The debuggers halt on a segmentation fault inside QObject destructor. The object deletion was requested by a call to deleteLater()
> >>
> >> Here is what I get in the stack trace:
> >>
> >> 0    QObject::~QObject    qobject.cpp    993    0x7ffff62c7580
> >> 1    RendererInterface::~RendererInterface    rendererinterface.cpp    119    0x60664f
> >> 2    RendererInterface::~RendererInterface    rendererinterface.cpp    137    0x60667e
> >> 3    qDeleteInEventHandler    qobject.cpp    4391    0x7ffff62d06e5
> >>
> >> How is it possible to have the destructor twice in the stack?? At the beginning I was thinking this was a GDB bug (GDB/MinGW under windows is buggy) but I get the same result when compiling the app under linux.
> >>
> >> Any idea how this can happen?
> >
> > Answer is definitely around lines 119-137 of rendererinterface.cpp
> 
> 
> You are calling delete on the same object into the destructor. You are doing something like that:
> 
> delete this
> 
> inside the destructor.
> 
> Maybe there is some internal variable that got the “this” value and force the object to try to destroy itself.
> 
> 

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