Boost C++ Libraries: Ticket #10992: Chrono IO state savers inconsistent with Boost.IO state savers

viboes — Mon, 16 Feb 2015 15:10:39 GMT

Please, could you be more explicit?

Are you referring to

    struct duration_style_io_saver
    {
      //! the type of the state to restore
      typedef std::ios_base state_type;
      //! the type of aspect to save
      typedef duration_style aspect_type;
      /**
       * Explicit construction from an i/o stream.
       *
       * Store a reference to the i/o stream and the value of the associated @c duration_style.
       */
      explicit duration_style_io_saver(state_type &s) :
        s_save_(s)
      {
        a_save_ = get_duration_style(s_save_);
      }
      /**
       * Construction from an i/o stream and a @c duration_style to restore.
       *
       * Stores a reference to the i/o stream and the value @c duration_style to restore given as parameter.
       */
      duration_style_io_saver(state_type &s, aspect_type new_value) :
        s_save_(s), a_save_(new_value)
      {
      }
      /**
       * Destructor.
       *
       * Restores the i/o stream with the duration_style to be restored.
       */
      ~duration_style_io_saver()
      {
        this->restore();
      }
      /**
       * Restores the i/o stream with the duration_style to be restored.
       */
      void restore()
      {
        set_duration_style(s_save_, a_save_);
      }
    private:
      duration_style_io_saver& operator=(duration_style_io_saver const& rhs) ;
      state_type& s_save_;
      aspect_type a_save_;
    };

status changed

viboes — Mon, 16 Feb 2015 15:12:51 GMT

status new → assigned

rkawulak — Mon, 16 Feb 2015 22:59:52 GMT

Yes. The second constructor should be implemented the following way to be consistent with IO state saver semantics (see for example basic_ios_iostate_saver):

duration_style_io_saver(state_type &s, aspect_type new_value) :
  s_save_(s), a_save_(get_duration_style(s))
{
  set_duration_style(s, new_value);
}

The same for all the remaining Chrono IO state savers.

viboes — Mon, 16 Feb 2015 23:27:21 GMT

Thanks for catching this point. I missed it completly. I should stop adding code that I don't test.

viboes — Mon, 16 Feb 2015 23:29:31 GMT

Have you find other cases?

rkawulak — Tue, 17 Feb 2015 00:01:20 GMT

IIRC, all IO state savers in Chrono library are implemented this way.

milestone changed

viboes — Tue, 17 Feb 2015 00:25:31 GMT

milestone To Be Determined → Boost 1.58.0

https://github.com/boostorg/chrono/commit/d08ef2352a68a8b616c7e14cf30066204907f019

rkawulak — Fri, 27 Feb 2015 04:21:46 GMT

Seems that not all documentation comments have been updated accordingly.

viboes — Fri, 27 Feb 2015 18:19:35 GMT

Ok, I will take a look.

status changed; resolution set

viboes — Mon, 09 Mar 2015 07:26:02 GMT

status assigned → closed
resolution → fixed

https://github.com/boostorg/chrono/commit/ec29de7bf0ea3a83ee54f449438624f8c15c8139