Where is the vtable located

Stack heap visualizer c. Why the sizeof gives different result for a object of a same class created in stack and heap?

Layout: fixed fluid. Web02 2. Strip HTML. Encode HTML. Paste as-is. Code block. Quoted Text. Best guess. Optional Password. Richard Deeming. It never changes and this array is shared by all instances of a given class. Each instance of a class that has virtual methods contains one vtable pointer for single inheritance , usually stored at offset 0, before all data members.

This pointer is initialized at construction time to point to the vtable for that class. As I said, the vtable is stored in the executable. The executable is memory mapped so basically it's stored in the same place where the code is, in memory that belongs to a memory mapped section, that's neither heap nor stack. And one more thing initialization of v-table take place under default constructor.

The vtable is built at compile time statically allocated. Each of the type instances contains a pointer to this table Because this pointer is initialized at construction time, a virtual member function should never be called from the constructor. Strictly speaking what the constructor initializes is the vtabe pointer of the object, not the vtable itself. Not sure what You mean. Where in memory is vtable stored? Please log in or register to add a comment.

Please log in or register to answer this question. Depends on compiler. B's Vtable ptr B's member variables. C's member variables. Related questions. Note that this is a common implementation of virtual calls, but is in no way enforced by the standard, so it could actually not be implemented like that at all but your chances are quite good. The compiler can also often bypass the virtual call system altogether if it has knowledge of the static type of your instance at compile time. Inspired by Jerry's answer, I managed to write up this function that can do the same thing for any function signature:.

True enough; so if the compiler knows the type of a most derived object, then it knows the offset of every subobject within that object. For such a purpose, a vtable is not needed. Here, f must be able to accept a pointer to any B object, including a B object that may be a subobject of a D object or of some other most derived class object.

When compiling f , the compiler doesn't know the full set of derived classes of B.