Calling member function that is being pointed.

[corrigan]

Here is my code:

#include <iostream>
using std::cout;
using std::endl;

class foo;

class bar
{
public:
    void (foo::*memberFunctionPointer)();
    void other(){((this)->*(this->memberFunctionPointer))();} //Error
};

class foo
{
public:
    bar myBar;
    void hello(){ cout << "hello" << endl;}
};

int main()
{
    foo testFoo;

    testFoo.myBar.memberFunctionPointer = &foo::hello;
    ((testFoo).*(testFoo.myBar.memberFunctionPointer))(); //OK
    testFoo.myBar.other();                                

    return 0;
}

Unfortunately, compiler stops at ((this)->*(this->memberFunctionPointer))();
with error:
pointer to member type 'void (foo::)()' incompatible with object type 'bar'

Thanks in advance for any help

[meesa]

You've got bad syntax.
Change the last part of the class such as:

//...
public:
    void hello(){ cout << "hello" << endl;}
}myBar; //This make a global foo::myBar. 

[imi]

Well, the problem is exactly what it's saying. You are trying to call a member function of class foo with a this-pointer of class bar.

((this)->*(this->memberFunctionPointer))();

The second this-> is redundant, since you are in the scope of bar, so lets write this as

((this)->*(memberFunctionPointer))();

you see? "this" is of type bar* here, whereas memberFunctionPointer is of type "void foo::*()", hence the error. If you want to call a member function of class foo within bar, then you either have to pass a foo* - parameter to other() or store such an object within bar.

Like this:

    void other(Foo& foo){(foo.*(this->memberFunctionPointer))();}
...
testFoo.myBar.other(testFoo);

or this:

class bar
{
    foo* pfoo;
public:
    bar(foo* f):pfoo(f) {}
    void other(){(pfoo->*(this->memberFunctionPointer))();}

Remember: Only because bar is a member variable of foo doesn't mean it knows it's surrounding foo instance when you call to testFoo.myBar.*

Ciao, Imi.