Re: mutable vs const_cast, which is better to modify field from const function?

struct MyObject{};

struct SomeClass
{
     SomeClass():myObject(0){}

     const MyObject * getMyObject()const
     {
         return getMyObject_impl();
     }

     MyObject * getMyObject()
     {
         return getMyObject_impl();
     }

private:

     const MyObject * getMyObject_impl()const
     {
         if(!myObject)
         {
             myObject = new MyObject();

         }
         return myObject;
     }

     MyObject * getMyObject_impl()
     {
         if(!myObject)
         {
             myObject = new MyObject();

         }
         return myObject;
     }

     mutable MyObject * myObject;
};

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So as long as all your other member functions access myObject via the
getMyObject_impl methods it should be ok.