RE: [osg-users] Event handler memory leak...

Jeff Kershner Mon, 21 Aug 2006 13:47:02 -0700

I understand about there not being enough information, and I apologize about this. Since I am so new to OSG, I assumed I was doing something wrong that was common for beginners.

I tried what you asked and I am getting the same crash at the same place. Am I declaring my derived EventHandler class correctly:

class EventHandler : public osgGA::GUIEventHandler

{

public:

EventHandler() {}

protected:

virtual ~EventHandler() {} // Thanks Thomas

public:

virtual bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)

{

return osgGA::GUIEventHandler::handle(ea, aa);

}

};

From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Don Burns
Sent: Monday, August 21, 2006 1:34 PM
To: osg users
Subject: Re: [osg-users] Event handler memory leak...

Hi Jeff,

I'm afraid I don't see enough information in the email to figure this one out, but it does look like you are trying to delete something on the stack.

This is a bit of a shot in the dark, but does anything change if you simply do this?:

m_Viewer.getEventHandlerList().push_front(new EventHandler);

-don

On 8/21/06, Jeff Kershner <[EMAIL PROTECTED]> wrote:

I have an EventHandler publicly derived from osgGA::GUIEventHandler (as well as I made sure there the destructor is virtual). I dynamically create an instance of my EventHandler class like this:

osg::ref_ptr<osgGA::GUIEventHandler> eh(new EventHandler());

m_Viewer.getEventHandlerList().push_front(eh);

My derived handle function is getting called correctly and everything seems to work. But when I exit out of my application I get an 'Unhandled exception.' My call stack in telling me the following:

MyApplicationName!EventHandler::`scalar deleting destructor'() + 0x42

MyApplicationName!EventHandler::`scalar deleting destructor'() + 0x5b

Any ideas?

From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Don Burns
Sent: Monday, August 21, 2006 1:10 PM

To: osg users
Subject: Re: [osg-users] Event handler memory leak...

Any time you call "new" you are dynamically allocating memory. So.... now I'm lost, what was the original question?

-don

On 8/21/06, Jeff Kershner <[EMAIL PROTECTED]> wrote:

That was the original allocation… but then I changed to this:

osg::ref_ptr<osgGA::GUIEventHandler> eh(new EventHandler());

m_Viewer.getEventHandlerList().push_front(eh);

From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Don Burns
Sent: Monday, August 21, 2006 12:46 PM

To: osg users
Subject: Re: [osg-users] Event handler memory leak...

What is this:

EventHandler* pEventHandler = new EventHandler();

(from your original message)

-don

On 8/21/06, Jeff Kershner <[EMAIL PROTECTED]> wrote:

Nothing is dynamically allocated in my test app and so I am not freeing or deleting anything.

From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Don Burns
Sent: Monday, August 21, 2006 12:09 PM

To: osg users
Subject: Re: [osg-users] Event handler memory leak...

Are you freeing something that was already being managed by a ref_ptr?

On 8/21/06, Jeff Kershner <[EMAIL PROTECTED]> wrote:

Thanks for the reply:

So now I declared my derived event handler class like this:

osg::ref_ptr<osgGA::GUIEventHandler> eh(new EventHandler());

m_Viewer.getEventHandlerList().push_front(eh);

But I am getting a crash in the msvcr71d.dll in free.c. I believe the error I am getting is this:

`scalar deleting destructor'() + 0x42

`scalar deleting destructor'() + 0x5b

So this is either MSVC++ 7.1 telling me that it is breaking on what it thinks to be a memory leak, or it is actually trying to free something that has already been freed. Since this crash only happens when I run with the debugger, I am leaning towards the first…

Any ideas?

From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Don Burns
Sent: Friday, August 18, 2006 4:54 PM
To: osg users
Subject: Re: [osg-users] Event handler memory leak...

Hi Jeff,

Note that the definition for EventHandlerList is:

typedef std::list< osg::ref_ptr<osgGA::GUIEventHandler> > EventHandlerList;

So, when you call

m_Viewer.getEventHandlerList().push_front(pEventHandler);

The address stored in pEventHandler is then managed by a ref_ptr, the reference count is incremented. When the Viewer's eventHandlerList goes out of scope, the reference on the address will be decremented, and if the result is a reference count of 0, it will be deleted. You should not delete it in your own code.

BTW, some compilers and profiling tools don't handle reference pointers well and may give you faulty information about memory leaks.

-don

On 8/16/06, Jeff Kershner <[EMAIL PROTECTED]> wrote:

I have an event handler class like this:

class EventHandler : public osgGA::GUIEventHandler

{

public:

virtual bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa);

};

The handle function just calls the base class' handle function…

This is how it is implemented:

EventHandler* pEventHandler = new EventHandler();

m_Viewer.getEventHandlerList().push_front(pEventHandler);

When my application exits, I get a memory leak that is caused by this EventHandler. Do I need to delete this EventHandler pointer?

It feels weird to delete a pointer that I am handing to another system…

Finally, as a side note, does the EventHandler class that I create need to have a virtual destructor explicitly written?

Thanks,

/jk

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RE: [osg-users] Event handler memory leak...

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