V table compiler option to see calss heirarchy

Use      g++ -fdump-class-hierarchy
Vtable for base
base::_ZTV4base: 3u entries
0     (int (*)(...))0
4     (int (*)(...))(& _ZTI4base)
8     base::printmyname

Class base
   size=8 align=4
   base size=8 base align=4
base (0xb6dd9c30) 0
    vptr=((& base::_ZTV4base) + 8u)

Vtable for derive1
derive1::_ZTV7derive1: 3u entries
0     (int (*)(...))0
4     (int (*)(...))(& _ZTI7derive1)
8     derive1::printmyname

Class derive1
   size=12 align=4
   base size=12 base align=4
derive1 (0xb6d6ca80) 0
    vptr=((& derive1::_ZTV7derive1) + 8u)
  base (0xb6dd9c6c) 0
      primary-for derive1 (0xb6d6ca80)

See Vtable compiler option

g++ -fdump-class-hierarchy