I this post, I've seen this:

class MonitorObjectString: public MonitorObject {
    // some other declarations
    friend inline bool operator==(/*const*/ MonitorObjectString& lhs,
                                  /*const*/ MonitorObjectString& rhs)
    { return lhs.fVal==rhs.fVal; }
}

Before we can continue, THIS IS VERY IMPORTANT:

• I am not questioning anyone's ability to code.
• I am just wondering why someone would need non-const references in a comparison.
• The poster of that question did not write that code.

This was just in case. This is important too:

• I added both /*const*/s and reformatted the code.

Now, we get back to the topic:

I can't think of a sane use of the equality operator that lets you modify its by-ref arguments. Do you?