In C++, Is there any way/ procedure to know whether particular class has been inherited by other class?
Is it possible in C++
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2there is some type_trait that is close to that http://www.cplusplus.com/reference/type_traits/is_base_of/ in C++11 – user2485710 Dec 19 '13 at 10:50
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You can use the `dynamic_cast` operator. See http://en.wikipedia.org/wiki/Dynamic_cast – Claudio Dec 19 '13 at 10:53
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no idea about type_trait. any other way? – hims Dec 19 '13 at 10:58
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2nd is I want to check @ compile time. – hims Dec 19 '13 at 10:59
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check at compile time with a final specifier – A. H. Dec 19 '13 at 11:02
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Even if you could do this, it would still be most useless. Inheritance is being used in lots of implementation details in lots of libraries, especially in those involving templates, due to EBO. – rightfold Dec 19 '13 at 11:04
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No, the language provides no such mechanism. – juanchopanza Dec 19 '13 at 11:06
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While the build is compiling you can use the IDE's search function to check the code base for `: public BaseClass` (where BaseClass is the name of the class in question). – Grimm The Opiner Dec 19 '13 at 11:17
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1@user1158692 won’t work with `template
class U : T`. :) – rightfold Dec 19 '13 at 11:19
1 Answers
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For example lets say you have the following two classes:
class A {};
class B : public A {};
If you ask if there is a way to know if A have been inherited then no there is no such way.
If you ask if there is a way to know if B inherits from another class (no matter what class it is) then no there is not.
The closest you can get is probably std::is_polymorphic, which tells (compile time) if a class have virtual functions that can be inherited, or if a class have virtual functions that it have inherited. There is no functionality, compile time or run time, to tell if a class have been inherited, or what the base-classes of some class is.
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I have checked for std::is_polymorphic, is a useful way to know whether class has virtual function that can be inherited. however how would i come to know how many derived classes has inherit the same base class? I think you have covered this in above mentioned replies that there is no such way to know that. Am i correct? – hims Dec 30 '13 at 08:59
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1@hims Yes, there is no way to know that. For that you need [introspection](http://en.wikipedia.org/wiki/Type_introspection) which C++ doesn't have. – Some programmer dude Dec 30 '13 at 11:10
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