static error

[Allan Bruce]

Hi there,
I get a linker error with the following, can somebody tell me how to remedy
it? the error is:
--------------------Configuration: WinGalaga - Win32
Release--------------------
Linking...
Weapon.obj : error LNK2001: unresolved external symbol "protected: static
int Weapon::mCurrLight" (?mCurrLight@Weapon@@1HA)
WeaponManager.obj : error LNK2001: unresolved external symbol "protected:
static int Weapon::mCurrLight" (?mCurrLight@Weapon@@1HA)
Release/WinGalaga.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

WinGalaga.exe - 3 error(s), 0 warning(s)


I am trying to initialise the lights from the WeaponManager by:
Weapon::InitLights();


Here is the header of the file where the problem exists


class Weapon : public GameEntity
{
friend class WeaponManager;

public:
Weapon(void);
virtual ~Weapon(void);

virtual void Draw(void);
void DrawLight(void);
static void InitLights(void){mCurrLight = GL_LIGHT1;}

...

protected:
...
// light stuff
static int mCurrLight;
};


Thanks
Allan

 

[Karl Heinz Buchegger]

Here is the header of the file where the problem exists

class Weapon : public GameEntity
{
friend class WeaponManager;

public:
Weapon(void);
virtual ~Weapon(void);

virtual void Draw(void);
void DrawLight(void);
static void InitLights(void){mCurrLight = GL_LIGHT1;}

...

protected:
...
// light stuff
static int mCurrLight;
};

this *declares* a variable mCurrLight. But it does not *define* it.
In other words: the above says: Somewhere there is a variable
called Weapon::mCurrLight and it has type int.
But where is that variable?
You have to define it somewhere, eg. in Weapon.cpp

#include "Weapon.h"

int Weapon::mCurrLight; // Here it is!!!

Weapon::Weapon()
{
...


Your textbook should have a section on statis class members. Doesn't it?

 

[Allan Bruce]

this *declares* a variable mCurrLight. But it does not *define* it.
In other words: the above says: Somewhere there is a variable
called Weapon::mCurrLight and it has type int.
But where is that variable?
You have to define it somewhere, eg. in Weapon.cpp

#include "Weapon.h"

int Weapon::mCurrLight; // Here it is!!!

Weapon::Weapon()
{
...


Your textbook should have a section on statis class members. Doesn't it?

Thanks, thats it working now.

My book does have a section on static members, but it is not explained very
well. I understand why you need the inclusion of Weapon::mCurrLight;

Thanks again
Allan

 

[Frank Schmitt]

Hi there,
I get a linker error with the following, can somebody tell me how to remedy
it? the error is:
--------------------Configuration: WinGalaga - Win32
Release--------------------
Linking...
Weapon.obj : error LNK2001: unresolved external symbol "protected: static
int Weapon::mCurrLight" (?mCurrLight@Weapon@@1HA)
WeaponManager.obj : error LNK2001: unresolved external symbol "protected:
static int Weapon::mCurrLight" (?mCurrLight@Weapon@@1HA)
Release/WinGalaga.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

WinGalaga.exe - 3 error(s), 0 warning(s)


I am trying to initialise the lights from the WeaponManager by:
Weapon::InitLights();


Here is the header of the file where the problem exists


class Weapon : public GameEntity
{
friend class WeaponManager;

public:
Weapon(void);
virtual ~Weapon(void);

virtual void Draw(void);
void DrawLight(void);
static void InitLights(void){mCurrLight = GL_LIGHT1;}

...

protected:
...
// light stuff
static int mCurrLight;
};

You have *declared* Weapon::mCurrLight, but you haven't *defined* it -
just add

int Weapon::mCurrLight;

to Weapon.cpp

HTH & kind regards
frank