Dynamic_pointer_cast return null

In this hierarchy, A is a virtual base class. You must first cast back to the complete E object, then work your way back up the hierarchy, in an unambiguous manner, to reach the correct B object. Class hierarchy that shows duplicate base classes.

Given an object of type E and a pointer to the D subobject, to navigate from the D subobject to the left-most A subobject, three conversions can be made. Considering cross casts, it is actually possible to do the conversion from a pointer to D to a pointer to the left-most A subobject in just two steps. You can perform a cross cast from D to B , then an implicit conversion from B to A. The value of a failed cast to pointer type is the null pointer. The following sample creates the base class struct A pointer, to an object struct C.

This, plus the fact there are virtual functions, enables runtime polymorphism. Casting Operators Keywords. Compiler support. Freestanding and hosted. Language support library. Technical specifications. Flow control. Function declaration. Lambda function expression. Fundamental types. Function types. Compound types. Storage duration specifiers. Default initialization. Value initialization.

Zero initialization. Copy initialization. I have a base class, an interface that inherits from that base class, and then a class that inherits from that one. But I would prefer if the dynamic cast worked.

EDIT: Here's a compact section of the code otherwise it's too long to put here. Tell me if you need more than the header files. Which has me at a complete loss. The code also worked until about a week ago when I made a change. When I reverted the change, the problem still occurred. Some code would help. The obvious first guess is that perhaps you forgot to give A a virtual destructor. It's hard to say without your definitions of A , B , and C , along with your usage.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Upcasting: Casting a derived class pointer or reference to a base class pointer or reference is known as upcasting. As we mention above for dynamic casting there must be one Virtual function. Suppose If we do not use the virtual function, then what is the result? Skip to content. Change Language.

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