[prog] C++ const method & static_cast

[Karine Proot]

Hello,

   I am trying to switch all my getters to const:
Tab *getPrevious();
   becomes
Tab *getPrevious() const;

   I have elsewhere:
buddyTab = static_cast<BuddyTab*>(tabs->getFirst()->getPrevious());

   This line fails at linking:
undefined reference to `Tab::getPrevious()'

   If someone could show me the light...

Karine