id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
7330	Patch adding move constructors and move assignments	Antony Polukhin	Douglas Gregor	"Use of move constructor and move assignment reduce memory allocation/deallocations count and do not call functor copy operator for big functors.
Example:
{{{
struct big_aggregating_structure {
    int disable_small_objects_optimizations[32];
    
    void operator()() {}
};

...

function<void()> f1 = big_aggregating_structure();
function<void()> f2 = f1; // will call new, copy()
function<void()> f3 = std::move(f1); // Just swaps pointers, leaves f1 empty
f3 = f2; // Will call new, copy(), destory(), delete
f3 = std::move(f2); // Just swaps pointers, leaves f2 empty (calls destory(), delete for f3)

{
    function<void()> f_new1 = big_aggregating_structure();
    function<void()> f_new2 = std::move(f_new1);
    // Without move constructor, there will be additional new, copy(), destroy(), delete calls
}

}}}

This patch could be very usefull for boost::asio, boost::thread and anyone, who uses boost::function in STL containers on C++11 compilers.
Patch was tested on MSVC2010, GCC-4.6"	Patches	closed	To Be Determined	function	Boost Development Trunk	Optimization	fixed