I have a code section of the form

auto myObject = someFunc <T> ();

someFunc returns an object of type T by value.

Despite setting T& T::operator= ( T const& other ) and T& T::operator= ( T && other ) to private. I get no compiler error.

How do I find out what the expression actually uses?

CodePudding user response：

In

auto myObject = someFunc <T> ();

no operator = is used. When you have

type_name variable_name = intializer

you are declaring and initializing an object and only constructors are used to initialize an object.

operator = is only used when you are doing assignment, and that only occurs after you've defined a variables.

In your code depending on a number of conditions you will either see return value optimization (RVO) or named return value optimization (NRVO) meaning you will only see one constructor call or a copy/move operation will happen and you will see two constructor calls happen. One for the object created in someFunc and the other to copy/move that value into myObject.

type_name variable_name = intializer; // initialization
variable_name = something;            // assignment