[boost] [Boost-bugs] [ boost-Bugs-1646100 ] No zero-argument in_place()

From: SourceForge.net (noreply_at_[hidden])
Date: 2007-01-27 14:30:24

Bugs item #1646100, was opened at 2007-01-27 11:30
Message generated for change (Tracker Item Submitted) made by Item Submitter
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Nobody/Anonymous (nobody)
Summary: No zero-argument in_place()

Initial Comment:
There is no zero-argument version of boost::in_place(). I would have expected this to exist, and to be a factory for a type's default constructor.

This is necessary when attempting to use boost::optional with a type that is not CopyConstructible, or where the copy constructor is expensive:

    #include <boost/optional.hpp>
    #include <boost/utility/in_place_factory.hpp>

    boost::optional<my_type> my_optional;
    my_optional = boost::in_place();

I'm not aware of any other way to initialise a boost::optional to a default-constructed instance without unnecessary and perhaps impossible copying.

--Clive.
  (clive-nospam-boost.org_at_[hidden])

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