Incorrect values from operator casting with reference

I'm trying to make a float wrapper (which will also do some magic stuff in the constructor).

However I find myself with quite odd errors.

class Foo {
public:
   Wrapper();

   operator const float& () const { return m_bar; }
   op开发者_如何学Cerator float& () { return m_bar; }

   const float& Get() const { return m_bar; }
   float& Get(){ return m_bar; }
private:
   float m_bar;
};

if I use Get() then I get the correct value but if I just use the cast operator then I get random values.

Isn't it possible cast a reference to a member?

As you stated in your comment, you're passing the class to a vararg function (I guess it is vararg by the formating). The vararg passing does not work because it passes the address of the class and not a cast type (it doesn't know what it should cast it to when passing).

Using Get or an explicit cast is the only solution if you need to use varargs.