Re: [boost] boost::scoped_array::release?

From: Ralf W. Grosse-Kunstleve (rwgk_at_[hidden])
Date: 2006-03-09 14:24:50

--- Peter Dimov <pdimov_at_[hidden]> wrote:

> Ralf W. Grosse-Kunstleve wrote:
> > --- Dan Day <coolmandan_at_[hidden]> wrote:
> >
> >> On 3/8/06, Ralf W. Grosse-Kunstleve <rwgk_at_[hidden]> wrote:
> >>
> >>> Are there arguments for not adding release()?
> >>
> >> Check the FAQ on the scoped_ptr documentation.
> >
> > Policing arguments ("you shouldn't to this") are OK only if there is
> > an alternative. As I wrote before, there is no auto_array, therefore
> > the FAQ is just frustrating.
> 
> I'm willing to add scoped_array::release if nobody objects and if you 
> contribute a test. But keep in mind that 1.34 is closed for new features. 

In the meantime I implemented auto_array, starting with the scoped_array
implementation:

  http://phenix-online.org/cctbx_sources/scitbx/include/scitbx/auto_array.h

For the future, eventually the same file should show up here with version
history:

  http://cvs.sourceforge.net/viewcvs.py/cctbx/scitbx/include/scitbx/

In contrast to the STLport implementation I use this approach to implement the
copy constructor (and similarly for the assignment operator):

  class auto_array
  {
      mutable T* ptr;

      auto_array(auto_array const& other)
      {
        ptr = const_cast<auto_array*>(&other)->release();
      }
  };

I know it works on a large number of platforms (several versions of EDG, VC,
g++). valgrind also didn't have any complaints. Is the approach also OK from a
theoretical viewpoint? Or is it necessary to adopt the more involved STLport
approach of introducing an auto_ptr_ref with a common base class for auto_ptr,
auto_ptr_ref?

I'd be happy to contribute my version back to boost. Then the FAQ wouldn't be
frustrating anymore and scoped_array could stay as is.

Cheers,
        Ralf

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