Peter Dimov wrote:
Michael Marcin: ...
For rvalues yes but for lvalues you need move emulation. Which can be implemented in the sandbox move library as follows.
class foo { public: foo(); foo( T t ); foo( boost::move_from<foo> other ) { swap( other.source ); }
foo& operator=( foo rhs ) { swap( rhs ); }
I see what you mean now, thanks. This is, I believe, the Adobe approach for move emulation:
http://stlab.adobe.com/group__move__related.html
It's based on the Adobe/Stepanov philosophy that all types are copyable, so it doesn't support move-only types. This takes away one motivation for having move. std::vector won't use adobe::move/boost::move, so this takes away the other motivation. What's left? :-)
Adobe may believe that all types are Regular but I have types that can't be copied (at least not efficiently) and I disallow their copying to prevent clients of my code from shooting themselves in the performance foot. The move library in the boost sandbox by Daniel James, which is a continuation of the work by others including Adobe, relaxes these constraints and supports move only types. I use it in some performance sensitive code or when I need/want stronger exception safety guarantees. Thanks, Michael Marcin