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Cannot Cast To Its Private Base Class


In D_publ, the public parts of B are public and the protected parts of B are protected (D_publ is-a-kind-of-a B). note that the slicing problem is still here –M.M Dec 21 '14 at 23:17 yes still here I'm reading the link you gave me it will take me a The 10'000 year skyscraper What did John Templeton mean when he said that the four most dangerous words in investing are: ‘this time it’s different'? Does The Amazing Lightspeed Horse work, RAW? his comment is here

Any ideas? Utilities 2.1 std::move is rvalue cast 2.2 std::move if noexcept 2.3 std::forward ... 2.6 is same Templates 3.1 alias template 3.2 template parameter pack 3.3 override virtual and template ... Linked 0 Typical problem on Inheritance 14 Why a simple mention of base pointer/reference in subsequent privately derived classes is forbidden? 5 Protected derived class 0 Failed and ill-formed casts Related What is really curved, spacetime, or simply the coordinate lines? http://stackoverflow.com/questions/28851739/cannot-cast-derived-to-its-private-base-class-base

Cannot Cast To Its Protected Base Class

Edit: here's the relevant reference from the spec - Section 4.10 Pointer conversions, paragraph 3: A prvalue of type "pointer to cv D", where D is a class type, can be Basically what is wrong with allowing this type of code in C++? c++ inheritance casting base-class class-visibility share|improve this question edited Dec 19 '11 at 9:12 asked Dec 19 '11 at 8:59 John 2,65042153 Please post real code. –curiousguy Dec 25 It's just an implicit cast to a private base from inside the class.

class A { ... }; class B : private A { const A &foo() const { return *((const A *)this); } }; Can I take a subclass that inherits privately from Anyway, what is the point? This claus also does not apply for the same reasons as above Consider the 4th bullet- Once again this clause does not apply Thus we can conclude that 'Base' is not Can I do this without it having virtual methods?

Making a large file using the terminal If I receive written permission to use content from a paper without citing, is it plagiarism? Private inheritance often means more or less the opposite: that the derived class uses a general base class to implement something with a more restricted interface. What is the definition of "rare language"? http://stackoverflow.com/questions/3738556/how-to-implement-casting-to-a-private-base-class-in-c Does a key signature go before or after a bar line?

And if A* p = new B; were allowed, then the inherited members of any B could be accessed from the outside world, just by making a A*. In a company crossing multiple timezones, is it rude to send a co-worker a work email in the middle of the night? Solutions? Additionally, there's a special rule for the C-style cast, see Bathsheba's answer. –dyp Jul 29 '13 at 13:39 "If you using C style cast, it will yes, because cast

C++ Public Inheritance

Probability of All Combinations of Given Events Does a key signature go before or after a bar line? this content I only want to override the function in my ProduceItem class and not my Celery class because I want the Celery class to inherit the overridden methods from ProduceItem. Cannot Cast To Its Protected Base Class Home Qt Development General and Desktop [Solved] Cannot cast QObject subclass to QObject [Solved] Cannot cast QObject subclass to QObject This topic has been deleted. C++ Virtual Function What are 'hacker fares' at a flight search-engine?

If I want to process these properties, it is obvious, that I'd rather cast them to their base type than to add an implementation for each variation. this content What is exactly meant by a "data set"? This kind of inheritance means "is implemented in terms of", while public inheritance is an "is-a" relation. –JBL Jul 29 '13 at 13:20 1 Why I would want this horrible Related 321How to call a parent class function from derived class function?557Difference between private, public, and protected inheritance25C++ cast to derived class1Do private elements in the base class add to the C++ Polymorphism

I would recommend that you avoid doing what you are trying to do, and do something else, like, say, define and use some ArrayOfLine rather than Array (of Object). Not the answer you're looking for? The 10'000 year skyscraper My manager said I spend too much time on Stack Exchange. weblink The reason the main() function doesn't know it is that you made class derived inherit PRIVATELY from class base.

Why had Dumbledore accepted Lupin's resignation? On the interface your type offers X, the implementation is done by registering in a particular API that requires that you extend a type T. Join them; it only takes a minute: Sign up Inheritance: 'A' is an inaccessible base of 'B' up vote 49 down vote favorite 13 $ cat inheritance.cpp #include using namespace

What would be the harm if the inheritance information is not hidden? –Lazer Mar 12 '12 at 5:08 1 Private inheritance is a form of aggregation/composition.

Newton's second law for individual forces Add comments to a Python script and make it a bilingual Python/C++ “program” Is it safe to use cheap USB data cables? If Object is not visible, then the designer of Line must have done that for a reason. This is a design question. One other option is to implement the cast operator in Line: class Line : protected Object { public: operator Object&(); }; and call the function like so: a.Add(Line()); instead of a.Add(new

Making a large file using the terminal Add comments to a Python script and make it a bilingual Python/C++ “program” How safe is 48V DC? Does the "bat wing" aircraft paint design have a proper name? share|improve this answer edited Mar 12 '12 at 5:03 answered Mar 12 '12 at 4:57 Carl Norum 148k19268349 add a comment| up vote 6 down vote private inheritance should only change http://electrictricycle.net/cannot-cast/cannot-cast-class-org-apache-axis2-jaxws-spi-provider-to-class-javax-xml-ws-spi-provider.html Without getting into a long-winded discussion of what would happen if it was allowed, the simple fact is that it's not allowed.

How small could an animal be before it is consciously aware of the effects of quantum mechanics? Those are meant to determine WHO can access methods, attributes or base classes. a has type Animal. (If you called this function with a Cat, then you sliced it). But they're still too close together. –nijansen Jul 29 '13 at 13:33 1 Recommend editing answer to explicitly state that this is a static_cast-like operation and not a reinterpret_cast –M.M

Find the function given its Fourier series Does sputtering butter mean that water is present? However users of PrivatelyDer should avoid this unsafe conversion, since it is based on a private decision of PrivatelyDer, and is subject to change without notice. dynamic_cast1852Cast int to enum in C#609Interface vs Base class1410Do I cast the result of malloc?1Base class -> Derived class and vice-versa conversions in C++8c++ casting base class to derived class mess1C++, This has both benefits (it allows derived classes of the protected derived class to exploit the relationship to the protected base class) and costs (the protected derived class can't change the

asked 6 years ago viewed 19724 times active 7 months ago Get the weekly newsletter! Which movie series are referenced in XKCD comic 1568? Join them; it only takes a minute: Sign up Cannot cast “derived” to its private base class “base” [duplicate] up vote 6 down vote favorite This question already has an answer How can I prove its value?

EDIT : For example I have: class A { //base class } class AX : private A { //a child } class AY : private A { //another specialized child } Tour C++ Super-FAQ Blog Forums Standardization About Features Working Draft of the nextstandard Current ISO C++ status Upcoming ISO C++ meetings Compiler conformance status Navigation FAQ Home