Peter Dimov wrote:
Michael Marcin: ...
It also allows you to support move assignment emulation rather elegantly using the move library in the sandbox.
There is no need to use a move library. The point of the above assignment is to take advantage of copy elision, which allows the compiler to construct the rvalue argument directly into 'arg', without a copy. In other words, if you have
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 ); } void swap(); //... }; T bar(); int main() { foo x; foo y( bar() ); x = boost::move(y); } Thanks, Michael Marcin