Re: [Boost-users] Problem with enable_shared_from_this and shared_ptr

Subject: Re: [Boost-users] Problem with enable_shared_from_this and shared_ptr
From: Ganeshram Iyer (ganeshramiyer_at_[hidden])
Date: 2010-08-06 10:14:28

Thanx Ryan. Very helpful. You have a comment that "This is where the
tr1::bad_weak_ptr happens". Is this something that still needs to be
addressed in your code or is there a solution already?
Thanks in advance
Ganesh

On Fri, Aug 6, 2010 at 2:40 AM, Ryan McConnehey <mccorywork_at_[hidden]>wrote:

>  Ganeshram Iyer wrote:
>
> Ryan,
> Is there any chance you can post what you added to your provided example to
> fix the problem you were having? I would love to see what that example looks
> like when it is working.
> Thanks in advance
> Ganesh
>
> Sorry for the delay in answering your question.  I missed it in my inbox.
> Anyway I've included what I changed in the code.  I didn't see any point in
> giving the user a choice in how pool was created when one of the option
> gives an error.  So, I added a static methods that creates a pool in a
> shared_ptr and hid the constructor.  This forced the user to get the pool
> inside a shared_ptr and removed the possibility of an error when calling the
> get method.
>
> Ryan
>
>
> [CODE]
>
> //C++ Includes
> #include <exception>
> #include <iostream>
> #include <vector>
> #include <algorithm>
>
> //Boost Includes
> #include <boost/shared_ptr.hpp>
> #include <boost/enable_shared_from_this.hpp>
>
> class pool : public boost::enable_shared_from_this< pool >  {
> private:
>  using boost::enable_shared_from_this< pool >::shared_from_this;
>
> private:
>  pool(){}
>
> public:
>  static boost::shared_ptr<pool> create(void) {
>    return boost::shared_ptr<pool>(new pool);
>  }
>
> public:
>  boost::shared_ptr<int> get(void)  {
>    boost::shared_ptr<pool> aPool = shared_from_this();   //This is where
> the tr1::bad_weak_ptr happens.
>    return boost::shared_ptr<int>(new int);
>  }
> };
>
>
> int main(int argc, char * argv[]) {
>  try {
>    boost::shared_ptr<pool> myPool = pool::create();
>
>    boost::shared_ptr<int> a = myPool->get();
>  }
>  catch (std::exception & exception)  {
>    std::cout << exception.what() << std::endl;
>  }
>
>  return 0;
> }
>
>
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>

-- 
Ganeshram Iyer
Open Source and CAD: http://ossandcad.blogspot.com
ganeshramiyer_at_[hidden]