const CFoo &bar() const

Question

I have a property of a class, for example, const CFoo &bar() const, what does it mean?

Answer 1

The method bar returns a reference to a const CFoo (that's the const CFoo & part before bar), and calling this method does not modify any variables that are not marked as mutable (that's the const after the parentheses).

See also the C++ FAQ Lite entries What does "Fred const& X" mean? and What is a "const member function"?.