class base{
   public:
   base()
   {

   }
   virtual int foo();
};

int base::foo()
{

}

class Derived : public base
{
   int foo();
};

int Derived::foo()
{

}

void _main()
{
   Derived A;
}

d:\MinGW\bin>d:\mingw\bin\gcc -ffreestanding -fpermissive -nodefaultlibs -nostdlib -c d:\myos\sources\test.cpp -o d:\myos\bin\test.o -lstdc++
d:\MinGW\bin>d:\mingw\bin\ld -Ttext 0x500000 --image-base 0x0 -o d:\myos\bin\test.bin d:\myos\bin\test.o
d:\myos\bin\test.o:test.cpp:(.rdata$_ZTI7Derived[__ZTI7Derived]+0x0): undefined reference to `vtable for __cxxabiv1::__si_class_type_info'
d:\myos\bin\test.o:test.cpp:(.rdata$_ZTI4base[__ZTI4base]+0x0): undefined reference to `vtable for __cxxabiv1::__class_type_info'