Why do I get a compilation error when I call a base-class function with a pointer to a pointer to an inherited class? Example: class cFoo {}; class cBar : public cFoo {}; void func1(cFoo *) {} // base class void func2(cFoo **) {} // base class void main(void) { cBar bar, *pbar; // inherited class func1(&bar); // compiles ...
Hi all! I'm currently working on integrating a third-party package that uses lots of RTTI stuff on a non-RTTI platform (Android). Basically, I did my own RTTI implementation but I'm stuck on a problem. The issue is that a lot of classes are having the diamond inheritance problem since all the classes derive from the same base class (ob...
Is there a way in C++ to construct your class such that given a pointer to your class you can instruct dynamic_cast<>() how to cast to another class for which you are wrapping the implementation? Would operator cast do the trick? Imagine I have an Abstract interface base class and derive a concreteA from this as well as concreteB, but ...
The dynamic_cast operator is returning zero (0) when I apply to a pointer that points to an instance of a multiply inherited object. I don't understand why. The hierarchy: class Field_Interface { public: virtual const std::string get_field_name(void) const = 0; // Just to make the class abstract. }; class Record_ID_Interface {...
Possible Duplicate: Regular cast vs. static_cast vs. dynamic_cast what is difference between static and dynamic cast in c++? ...
Environment: Linux C++ / Qt 4x I do not understand why the following downcast returns NULL? I pasted base and derived class below. Thanks in advance for any tips or suggestions. -Ed void MainWindow::onRtledaEventHandler(fes::EventArgs eventArgs) { // This cast returns a NULL ? fes::AtsCommandEventArgs* atsCommandEventArgs = d...
I want to cast this: class Base { public: virtual ~Base(){}; }; class Der : public Base {}; int main() { const Base* base = new Der; Der* der = dynamic_cast<Der*>(base); // Error return 0; } What should I do? I tried to put: const Der* der = dynamic_cast<Der*>(base); to mantain the const but this doesn't work. ...
(I applogise in advance for the length of this post, however the problem is fairly complex - hopefully everything is clear however I have simplified the scenario a lot and so there is a good chance that I've missed a vital fact, or there is something that I've not explained.) Setting the scene I'm using code generation to generate C# w...
For instance I have code like that class Base1 { virtual void wonderFULL() = 0; }; class Base2 { // all this weird members }; class Derived : public Base1, public Base2 { // not so weird members }; int main() { Derived Wonder; magicFunction(&Wonder); return 0; } void magicFunction(Base2 *ptr) { if (Base1 *b1 = dynamic_...
The below code explains the problem. Fill in same_sub_class to detect if the two pointers to virtual base class A are in fact the same concrete class. struct A { ... }: struct B : public A { ... }: struct C : public A { ... } bool same_sub_class(A * a1, A * a2){ // Fill this in to return true if a1 and a2 are //...
(Please no advise that I should abstract X more and add another method to it.) In C++, when I have a variable x of type X* and I want to do something specific if it is also of type Y* (Y being a subclass of X), I am writing this: if(Y* y = dynamic_cast<Y*>(x)) { // now do sth with y } The same thing seems not possible in Java (or...
Possible Duplicate: How is dynamic_cast typically implemented? Hi! how does dynamic_cast actually work? where does the runtime know from whether some piece of memory actually fits the datatype or not? Thanks! ...
Before reading the question: This question is not about how useful it is to use dynamic_cast. Its just about its performance. I've recently developed a design where dynamic_cast is used a lot. When discussing it with co-workers almost everyone says that dynamic_cast shouldn't be used because of its bad performance (these are co-workers ...