Re: const pointer to class problem

> class FOO {
> public:
>     int Version(void){return m_ver;};
[...]
>   };
>
> void PrintVer(const FOO * fp)
>   {
>   int v = fp->Version();  /* error here */

> If I remove the const from the routine declaration, it works fine, but
> I'd rather not do that.   I guess I don't understand what the compiler
> is trying to tell me, and have no idea of how to work around this
> without removing the const.

Your subject says "const pointer to class" but it's not.  It's a [non-
const] pointer to a const object.  To answer your question, since the
object--not the pointer-- is const, you cannot call functions on it
unless they are also "const".  (The presumption is that const
functions don't modify the object, so it remains unchanged.  Ignore
the "mutable" keyword and casting, and it works out pretty well.)

When you write a member function that does not change the object (e.g.
FOO::Version()), declare the function const. Then it can be called on
a const or non-const object:

class FOO  {
public:
     int Version() const {return m_ver;}
//...
};

Note the "const" after the parameter list.

--
Chris


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