Moving rvalue inside class member

Question

I've been browsing for a while in search of an answer but I don't seem to find it. So I decided to specifically ask the question here.

I've been trying to use something like this (and variants hereof):

struct NonCopyable
{
    NonCopyable() { };
    NonCopyable(const NonCopyable& other) = delete;
    NonCopyable(NonCopyable&& other) {  };
};

struct Host
{
    Host(NonCopyable&& nc) : m_nc(nc) { }
    NonCopyable m_nc;
};

to achieve this:

Host h(NonCopyable());

In other words, I'd like to construct NonCopyable inside the m_nc. Is this at all possible?

Answer 1

Note that nc is an lvalue as a named parameter, you need to convert it to rvalue, e.g. via std::move

Host(NonCopyable&& nc) : m_nc(std::move(nc)) { }

EDIT

There's a most vexing parse issue. Host h(NonCopyable()); is not a variable definition, but a function declaration; which declares a function named h, which returns Host and takes an unnamed parameter with type of function pointer (which takes nothing and returns NonCopyable).

Just change it to Host h{NonCopyable()};.