Passing a pointer to a class member function as a parameter

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You cannot cast a function pointer to void*.

If you want a function pointer to point to a member function you must declare the type as

ReturnType (ClassType::*)(ParameterTypes...)

Further you cannot declare a function pointer to a bound member function, e.g.

func_ptr p = &t1.get_pc // Error

Instead you must get the address like this:

func_ptr p = &test::get_pc // Ok, using class scope.

Finally, when you make a call to a function pointer pointing to a member function, you must call it with an instance of the class that the function is a member of. For instance:

(this->*cb_func)(); // Call function via pointer to current instance.

Here’s the full example with all changes applied:

#include <iostream>

class test {
public:
    typedef void (test::*callback_func_ptr)();
    callback_func_ptr cb_func;
    void get_pc();
    void set_cb_ptr(callback_func_ptr ptr);
    void call_cb_func();
};

void test::get_pc() {
    std::cout << "PC" << std::endl;
}

void test::set_cb_ptr(callback_func_ptr ptr) {
    cb_func = ptr;
}

void test::call_cb_func() {
    (this->*cb_func)();
}

int main() {
    test t1;
    t1.set_cb_ptr(&test::get_pc);
    t1.call_cb_func();
}

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