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List:       kde-devel
Subject:    Re: Object crashes app after being deleted
From:       Michael Pyne <michael.pyne () kdemail ! net>
Date:       2006-09-26 19:36:27
Message-ID: 200609261536.32411.michael.pyne () kdemail ! net
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On Monday 25 September 2006 17:22, Robert Hogan wrote:
> Hi there,
>
> An event from the tork object causes the deletion of the client object.
> There's stuff still going on in the client object (called from the tork
> object) , which I would expect to cease once it's destroyed.
>
> However, it appears to continue and since the stuff it needs is no longer
> available (because the client object is being deleted) it crashes.
>
> What do I need to do here? I'm pretty sure I'm missing something blindingly
> obvious.

Is the thing that you are deleting a QObject?  If so you might want to call 
deleteLater() on it instead of deleting it right then.

C++ tidbit:

If you delete an object while that object has code that that is running, the 
code will still try to go to completion in the function.

e.g.

void MyClass::foo()
{
  printStuff();
  print(this->m_a);
  // If you delete object when it is running here...

  ::doMoreStuff(); // It keeps running!
  
  // But it doesn't crash til here as long as doMoreStuff
  // doesn't reference this object.
  this->keelOver(); // this points to freed memory
}

If it's not a QObject you need to restructure your code such that the object 
is not deleted until it is finished being used.  Shared pointers may help you 
out with that.

Regards,
 - Michael Pyne

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