Virtual Method Table

• Each class of object has a list of function pointers called the "vtable."
• Each method the object understands has an index within this table.
• To call a virtual method you find the index of that method, then look at the virtual table for the object, and call the procedure at this location.

C++ "virtual" methods use this technique.

It is compatible with objects added at runtime and across libraries.

It involves long indirect jumps which can take up to ~10% of a program's runtime.

• Understanding Virtual Tables