Unresolved External (abstract class constructor/destructor) - c++

Question

So, I have an abstract class Panel and an implementation of it MyPanel. They look similar to this:
class Panel : public QWidget
{
public:
Panel(QWidget* parent = 0) = 0;
virtual ~Panel() = 0;
// but wait, there's more!!
};
class MyPanel : public Panel
{
public:
MyPanel(QWidget* parent = 0);
~MyPanel() {}; // nothing to do here
};
MyPanel::MyPanel(QWidget* parent) :
Panel(parent)
{
// you must construct additional pylons
}
I'm getting linker errors for the constructor/destructor from VC++
error LNK2019: unresolved external symbol "public: virtual __thiscall Panel::~Panel(void)" (??1Panel##UAE#XZ) referenced in function "public: virtual __thiscall MyPanel::~MyPanel(void)" (??1MyPanel##UAE#XZ) mypanel.obj
error LNK2019: unresolved external symbol "public: __thiscall Panel::Panel(class QWidget *)" (??0Panel##QAE#PAVQWidget###Z) referenced in function "public: __thiscall MyPanel::MyPanel(class QWidget *)" (??0MyPanel##QAE#PAVQWidget###Z) mypanel.obj
Why am I getting this linker error?
--- THE ANSWER ---
class Panel : public QWidget
{
public:
Panel(QWidget* parent = 0) : QWidget(parent) {};
virtual ~Panel() {};
// but wait, there's more!!
};
I thought I had tried this before lunch. Turns out I was wrong.

Answer 1

there is no such thing like virtual constructor.
You still should provide implementation of destructor.

Answer 2

Purely virtual destructors still need to have an implementation.
To expand on that a bit:
The destructor of a class will always be called if any instance of a subclass gets destructed, so it needs to have an implementation. (Basically the only effect of making a destructor purely virtual is that it prevents instanatiation of the class).
As for the constructor: You're making it purely virtual (which I don't see any reason for doing), but then you explicitly call it from the subclass's constructor.