C++11 move constructor not called, default constructor preferred
07:24 27 Oct 2012

Suppose we have this class:

class X {
public:
    explicit X (char* c) { cout<<"ctor"<

and this sample usage:

X x("test");
cout << x.c() << endl;
X y(x);
cout << y.c() << endl;
X z( X("test") );
cout << z.c() << endl;

The output is:

ctor
test
copy
test
ctor   <-- why not move?
test

I am using VS2010 with default settings. I'd expect the last object (z) to be move-constructed, but it's not! If I use X z( move(X("test")) ); then the last lines of the output are ctor move test, as I'd expect. Is it a case of (N)RVO?

Q: Should the move-ctor be called according to the standard? If so, why isn't it called?

c++ c++11 move-semantics