#include <stdio.h>

typedef const char EventArgs;

class EventCallback
{
public:
    virtual ~EventCallback () {}
    virtual bool operator () (EventArgs *evargs) = 0;
};

class EventMethodCallback : public EventCallback
{
    bool (*callback) (void *self, EventArgs *evargs);
    void *self;

public:
    template <class T>
    EventMethodCallback (bool (T::*f) (EventArgs *), T *_self)
    {
        callback = (bool (*) (void *, EventArgs *)) *((void **)&f);
        self = _self;
    }

    virtual bool operator () (EventArgs *evargs)
    {
        return callback (self, evargs);
    }
};

void invoke_event (EventCallback *ec)
{
    bool rc = (*ec) ("abcdef");
    printf ("rc = %d\n", rc);
}

// test class
class X
{
    int a, b;
public:
    X ()
    {
        a = 123;
        b = 456;
    }

    bool callback (EventArgs *evargs)
    {
        printf ("Callback: a=%d b=%d args=%s\n", a, b, evargs);
        return true;
    }
} x;

int main ()
{
    EventCallback *ec = new EventMethodCallback (&X::callback, &x);
    invoke_event (ec);
    delete ec;

    return 0;
}

/*
Results:

[3|zap@zap|~/eeeeeeee]./test
Callback: a=123 b=456 args=abcdef
rc = 1
*/