Hmm, not sure why it wouldn't compile for you, I'm using VisualStudio 2005
with OSG 2.6.
Thanks for the link.
Chris.
----- Original Message -----
From: "Paul Melis" <[EMAIL PROTECTED]>
To: "Chris Denham" <[EMAIL PROTECTED]>; "OpenSceneGraph Users"
<[email protected]>
Sent: Tuesday, November 18, 2008 5:37 PM
Subject: Re: [osg-users] A very simple ref_ptr memory leak example.
What compiler are you using? The snippet doesn't compile for me with gcc
4.1.2.
It's not hard indeed to create cycles, and handling them robustly would
mean checking for every reference stored in a Referenced instance if
there isn't a cycle.
Which is not impossible, but adds a lot of overhead I suspect.
See Caveat #4 in
http://andesengineering.com/OSG_ProducerArticles/RefPointers/RefPointers.html
Paul
Chris Denham wrote:
I'm probably treading very old ground here to do with circular usage
of ref_ptr, but it's new to me and I couldn't find any references in
the mail archive about users with similar problems.
I have pasted below, a very simple example of my usage of ref_ptr that
leaks memory.
I can see why it leaks and the destructors are never called, but I am
looking for any good tips on how best to guard against such a scenario.
Do I need to use weak ref pointers to implement this scenario
properly? Can that be done with ref_ptr? I could call unref but that
seems like a bad idea.
It seemed such an easy trap to fall into, I wondered why it doesn't
crop up more often? And if it does, how others have dealt with
circular problems of this type in OSG?
Chris Denham
//------------------------------------------
#include <osg/ref_ptr>
#include <osg/Referenced>
#include <iostream>
int main(int argc, char* argv[])
{
struct B;
struct A : public osg::Referenced
{
~A() { std::cout << "A::~A() called" << std::endl; }
osg::ref_ptr<B> b;
};
struct B : public osg::Referenced
{
~B() { std::cout << "B::~B() called" << std::endl; }
osg::ref_ptr<A> a;
};
osg::ref_ptr<A> a = new A();
osg::ref_ptr<B> b = new B();
a->b = b;
b->a = a;
return 0;
}
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