Are all temporaries rvalues in C++?

Question

I have been coding in C++ for past few years. But there is one question that I have not been able to figure out. I want to ask, are all temporaries in C++, rvalues?

Answer 1

Prasoon Saurav already linked a very good clc++ thread. In there, James Kanze explains why the question doesn't really make sense. It boils down to:

• rvalue-ness is a (boolean) property of expressions - each expression is either an lvalue or an rvalue
• temporaries are not expressions

For that reason, the question doesn't make sense.

A good example is the following code:

int main() {
  const int& ri = 4;
  std::cout << ri << std::endl; 
}

The temporary int with value 4 is not an expression. The expression ri that's printed is not a temporary. It's an lvalue, and refers to a temporary.