Construct std::function with a constructor based on template

Question

Is it possible to construct a std::function with the constructor of a type defined by a template argument?

For example:

template 

        

Answer 1

I don't think so, because constructors don't have names, you can't take a pointer/reference to them, and in general they don't behave quite like functions.

You could use a lambda to initialize a std::function with the same signature:

const std::function<T()> func = [](void) { return T(); } // or something like that

Calling it produces the same result as using the expression T() to construct a temporary of type T, but possibly with different side-effects. In the case of a true function call there's an extra temporary in the return statement, which nominally is copied/moved to the return value. The implementation may or may not elide the extra temporary.