Undefined reference to vtable (out of ideas) - c++

Question

I have gone through all I could find on net but seems like I am missing some very basic thing, having spent so much time on this problem isn't making things easier, so I will go ahead and ask for a help here, see if you can find what I am doing wrong.
Here is the code :
jControl.h
#ifndef _JCONTROL_H
#define _JCONTROL_H
namespace view
{
class jControl
{
public:
HWND hwnd;
HWND hParent;
HBITMAP hbitmap;
std::string text;
HFONT hFont;
COLORREF textColor;
COLORREF backgroundColor;
RECT updateRegion;
bool isUpdateRegion;
public:
jControl ( );
jControl ( HWND parent, HINSTANCE hInstance, WORD bitmap );
~jControl ( );
virtual void show ( );
virtual void hide ( );
virtual void disable ( );
virtual void enable ( );
virtual std::string getText ( );
virtual void setText ( std::string txt );
virtual void setUpdateRegion ( RECT rect );
virtual void setTextColor ( COLORREF crf );
virtual void setBackgroundColor ( COLORREF crf );
virtual void setFont ( HFONT font );
virtual bool setRange ( int range );
virtual bool setStep ( int step );
};
};
#endif
jControl.cpp
#include "jControl.h"
namespace view
{
jControl::jControl( ){};
jControl::jControl ( HWND parent, HINSTANCE hInstance, WORD bitmap )
: hParent ( parent ), hbitmap ( NULL ), isUpdateRegion ( false ), textColor ( RGB ( 255, 255, 255 ) ), backgroundColor ( RGB ( 54, 54, 54 ) )
{
hFont = ::CreateFont ( 18, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, "Myriad Pro" );
if ( bitmap != 0 ) hbitmap = LoadBitmap ( hInstance, MAKEINTRESOURCE ( bitmap ) );
};
jControl::~jControl ( )
{
if ( hbitmap ) DeleteObject ( hbitmap );
if ( hFont ) DeleteObject ( hFont );
if ( hwnd ) DestroyWindow ( hwnd );
};
void jControl::show( ) { ::ShowWindow( hwnd, SW_SHOW ); };
void jControl::hide( ) { ::ShowWindow( hwnd, SW_HIDE ); };
void jControl::disable ( ) { EnableWindow ( hwnd, false ); };
void jControl::enable ( ) { EnableWindow ( hwnd, true ); };
std::string jControl::getText ( ) { return text; };
void jControl::setText ( std::string txt ) { text = txt; InvalidateRect ( hwnd, NULL, true ); };
void jControl::setUpdateRegion ( RECT rect ) { updateRegion = rect; isUpdateRegion = true; };
void jControl::setTextColor ( COLORREF crf ) { textColor = crf; };
void jControl::setBackgroundColor ( COLORREF crf ) { backgroundColor = crf; ::InvalidateRect ( hwnd, NULL, true ); };
void jControl::setFont ( HFONT font ) { hFont = font; };
bool jControl::setRange ( int range ) { return true; };
bool jControl::setStep ( int step ) { return true; };
};
jProgressBar.h
#ifndef _JPROGRESSBAR_H
#define _JPROGRESSBAR_H
/** * Parent class include */
#ifndef _JCONTROL_H
#include "../jControl/jControl.h"
#endif
namespace view
{
class jProgressBar : public jControl
{
public:
jProgressBar ( std::string txt, int x, int y, int width, int height, HWND parent, HINSTANCE hInstance, WORD bitmap );
~jProgressBar ( );
std::string getText ( );
void setText ( std::string txt );
bool setRange ( int range );
bool setStep ( int step );
};
};
#endif
jProgressBar.cpp
#include "jProgressBar.h"
namespace view
{
jProgressBar::jProgressBar( std::string txt, int x, int y, int width, int height, HWND parent, HINSTANCE hInstance, WORD bitmap )
: jControl( parent, hInstance, bitmap )
{
hwnd = CreateWindowEx ( WS_EX_TOPMOST, PROGRESS_CLASS, txt.c_str(), WS_CHILD | WS_CLIPSIBLINGS | WS_CHILD, x, y, width, height, parent, 0, hInstance, 0 );
};
jProgressBar::~jProgressBar ( ){};
bool jProgressBar::setRange ( int range )
{
if ( SendMessage ( hwnd, PBM_SETRANGE, 0, MAKELPARAM ( 0, range ) ) != 0 ) return true;
return false;
};
bool jProgressBar::setStep ( int step )
{
if ( SendMessage ( hwnd, PBM_SETSTEP, ( WPARAM ) step, 0 ) != 0 ) return true;
return false;
};
};
And here is the error :
[Linker error] jProgressBar/jProgressBar.cpp:14: undefined reference to `vtable for view::jProgressBar'
I get the error on Constructor and Destructor of JProgressBar.

Answer 1

The problem may be in these lines:
std::string getText( );
and
void setText( std::string txt );
in jProgressBar.h
Please provide a definition for this function in Cpp or remove it from header, I think it should compile. The main reason is: you have overridden a virtual function in a child class with a declaration, but haven't given a definition for the method.
The compiler knows about the function, but the linker is not able to find the definition
For example:
class Base
{
virtual void f() = 0;
}
class Derived : public Base
{
void f();
}