Why can I call a non-const member function pointer from a const method?
- by sdg
A co-worker asked about some code like this that originally had templates in it.
I have removed the templates, but the core question remains: why does this compile OK?
#include <iostream>
class X
{
public:
void foo() { std::cout << "Here\n"; }
};
typedef void (X::*XFUNC)() ;
class CX
{
public:
explicit CX(X& t, XFUNC xF) : object(t), F(xF) {}
void execute() const { (object.*F)(); }
private:
X& object;
XFUNC F;
};
int main(int argc, char* argv[])
{
X x;
const CX cx(x,&X::foo);
cx.execute();
return 0;
}
Given that CX is a const object, and its member function execute is const, therefore inside CX::execute the this pointer is const.
But I am able to call a non-const member function through a member function pointer.
Are member function pointers a documented hole in the const-ness of the world?
What (presumably obvious to others) issue have we missed?
