What is undefined reference to Vtable?

When linker says “undefined reference to vtable for IBase” it basically means that Derived has vtable reference to IBase but it can’t find any compiled object code of IBase to look up to. So the bottom line is that class IBase has declarations without implementations.

Is a pure virtual function C++?

A pure virtual function is a virtual function in C++ for which we need not to write any function definition and only we have to declare it. It is declared by assigning 0 in the declaration. If an Abstract Class has derived class, they must implement all pure virtual functions, or else they will become Abstract too.

What is virtual destructor in C++ with example?

Deleting a derived class object using a pointer of base class type that has a non-virtual destructor results in undefined behavior. To correct this situation, the base class should be defined with a virtual destructor. For example, following program results in undefined behavior.

What is reference variable C++?

Reference variable is an alternate name of already existing variable. It cannot be changed to refer another variable and should be initialized at the time of declaration and cannot be NULL. The operator ‘&’ is used to declare reference variable.

What causes the ” undefined reference to vtable ” error?

In summary, there are three key causes of the “undefined reference to vtable” error: 1 A member function is missing its definition. 2 An object file is not being linked. 3 All virtual functions have inline definitions.

Where does the name vtable come from in C + +?

The name “vtable” comes from ” v irtual function table “. It is a table that stores pointers to (virtual) functions. A compiler chooses its convention for how the table is laid out; a simple approach is to go through the virtual functions in the order they are declared within class definitions.

What does undefined reference to vtable for iBase mean?

However as Derived overrides methods from IBase, it has vtable attached to it that will reference IBase. When linker says “undefined reference to vtable for IBase” it basically means that Derived has vtable reference to IBase but it can’t find any compiled object code of IBase to look up to.

Why do I not have a vtable in G + +?

In particular, G++ emits the vtable along with the implementation of the first-declared non-inline function in a class. Omitting its implementation means you won’t have a vtable, and thus won’t be able to construct the class (hence these errors). In short, define every function you declare, except for pure virtuals.

What is undefined reference to Vtable? When linker says “undefined reference to vtable for IBase” it basically means that Derived has vtable reference to IBase but it can’t find any compiled object code of IBase to look up to. So the bottom line is that class IBase has declarations without implementations. Is a pure virtual…