Re: [Boost-users] [shared_ptr] Is it possible for a shared_ptr to hand over it ownership

25 Dec 2008

      On Thu, Dec 25, 2008 at 4:57 AM, Max  wrote:
...
Suppose I have a shared_ptr which is the only owner of the pointee.
I hope there is a way to hand over its ownership to another object
without rendering the pointee being deleted.
Or, if the answer is no, is there an alternative class that has
this feature?
The use case is like this:
B b;
{
shared_ptr p1(A()), p2(A());
b.GetOwnership(p1.HandOver());
// now p1 is empty
}
That's not possible because in general shared_ptr can use custom
deleters and/or aliasing which B can't deal with, unless it's
shared_ptr itself. :)

Consider:

boost::shared_ptr<FILE>
open_file( char const * name, char const * mode )
{
  if( FILE * f=fopen(name,mode) )
    return boost::shared_ptr<FILE>(f,fclose);
  else
    boost::throw_exception(file_open_error());
}

Emil Dotchevski
Reverge Studios, Inc.
http://www.revergestudios.com/reblog/index.php?n=ReCode