**2.3 Structure of virtual function tables in multiple inheritance**

In BiCOMC, an object that inherits multiple interfaces has as many vftptr pointers as the number of inherited interfaces. Note that the basic structure of the virtual function table is described in Section 2.2. **Figure 3** shows the structure of the virtual function tables of an object inheriting three interfaces.

In the case where three interfaces have been inherited, three vftptr pointers exist as shown in **Figure 3**. Assume that a 32bit system is used and the next offset of the virtual function **Table 1** is 4, which is the difference between the address of vftptr 2 and the address of vftptr 1 in the instance of class. And the next offset of the virtual function **Table 3** is −8, which is the difference between the address of vftptr 1 and the address of vftptr 3.

#### *Computer Methods and Programs in Biomedical Signal and Image Processing*

#### **Figure 3.** *Structure of virtual function table in the case of multiple inheritance.*


#### **Table 1.**

*Tests of the binary compatibility in BiCOMC.*
