the object has type qualifiers that are not compatible with the member function using vector

Question

The example generates the error

the object has type qualifiers that are not compatible with the member function

and I can't figure out why.

Ah

class A {
public:
   void f2(XXX* ..) const;
protected:
   const vector<XYZ> f(){return m;}
   vector<XYZ> m;
}

A.cpp

void A::f2(XXX* ..) const
{
const vector<XYZ>& P= this->f(); // Here I get this error as well
}

Can someone explain me what I've done wrong? Thanks.

Answer 1

You can't call a non-const function from a const function. This means that f needs to be const qualified as well:

const std::vector<XYZ> f() const { return m; }

otherwise you can't call it from f2 .