C++ operators overloaded as a consequence ('+', '+=')

Question

When I overload, lets say, the '+' operator for a class in C++

MyClass MyClass::operator+(MyClass _c){
    //code here
}

Does it automatically apply to the '+=' operator? Does the compiler automatically substitute that for its longer conuterpart (a+=b <--> a=a+b)? Or is it a runtime operator function?

Answer 1

No. It doesn't. You need to overload those as well.