if vptr is created when object is created then why the size of class having virtual function comes as 4 on 32 bit sys and 8 on 64 bit machine solved if vptr is created when object is created then why the size of class having virtual function comes as 4 on 32 bit sys … Read more
A few things. First name your functions sensible things, those names are gibberish and mean nothing to anyone on here. Second, you’re error is quite simple. The “Wolf” and “Animal” class do not need to re-declare “inicjatywa,” so long as they declare their inheritance of “Organizmy” to be public (as they have) the ‘outside world’ … Read more
Your basic assumption is incorrect. The size of the object does not increase with the number of virtual functions. If the class has ANY virtual functions then it has a single pointer to a vtable for that class. The size of the object won’t change beyond that regardless how many virtual functions: struct s0 {}; … Read more
With virtual inheritance, the most derived class should call virtual base constructor, so: struct D : C<B> // D: ThermostatedRotorJobQueueFactoryStub { D(const X& x, const Y& y) : A(this), C(this, x, y) { cout << “D constructor” << endl; } }; But that is also true for C<B>: template <> struct C<B> : B { … Read more
You create an instance of B that is lets say “Bigger”, but the variable ‘a’ is converted into class A that is “Smaller” and contains the method print A. You did something similar to: A : IClass B : IClass The interface exposes some method that is in both A and B, and you to … Read more
Are you sure the definition is actually defining function onChar in class Game and not in class Screen? If you accidentally wrote this as the definition for onChar (which I can imagine could easily happen): void Screen::KeyListener::onChar(char c) {} then you are defining function in class Screen. solved is there an equivalent to ‘classname.this’ from … Read more
There are many possible reasons, but four come immediately to mind. The IP address is invalid. The IP address is unreachable because of an error in routing table configuration on intermediate nodes. A firewall somewhere is refusing to admit the traffic. The target host has inetd so configured as not to accept inbound telnet requests. … Read more
You’re right, C::fn() is called when my example is ran alone. My problem actually was that I was dynamically loading this class (C) with ros:pluginlib (http://ros.org/wiki/pluginlib) so the multiple inheritance issue is probably coming from there. That’s a completly different issue I’ll have to look into. solved C++: virtual functions with multiple derivations