Argthtjtr

I'm getting this compiler error. I have several hundred lines of code, so I'll post some that I think might be relevant but you'll need to tell me what you want to see.

Here's the error I get at compile time:

/tmp/ccBE5kZ5.o:game.cpp:(.text+0x1067): undefined reference to `vtable for Person'

/tmp/ccBE5kZ5.o:game.cpp:(.text+0x17a5): undefined reference to `vtable for Person'

/tmp/ccBE5kZ5.o:game.cpp:(.text+0x1ee6): undefined reference to `vtable for Person'

/tmp/ccBE5kZ5.o:game.cpp:(.text+0x2560): undefined reference to `vtable for Person'

/usr/lib/gcc/i686-pc-cygwin/3.4.4/../../../../i686-pc-cygwin/bin/ld: /tmp/ccBE5kZ5.o: bad reloc address 0xc in section `.text$_ZN6WeaponD1Ev[Weapon::~Weapon()]'

/usr/lib/gcc/i686-pc-cygwin/3.4.4/../../../../i686-pc-cygwin/bin/ld: final link failed: Invalid operation

collect2: ld returned 1 exit status

Here's the declaration of my Person class and my Weapon class, and the Actor class the Person is a descendant of:

class Actor {

public:

virtual void act();

virtual string getName();

virtual void setName(string n);

Actor();

Actor(string n);

virtual ~Actor();

private:

string name;

};





class Person : public Actor {

public:

void act();

virtual void fight(Person enemy);

virtual void takeDamage(double dmg);



// getters and setters

virtual unsigned getX();

virtual void setX(unsigned amt);

virtual unsigned getY();

virtual void setY(unsigned amt);

virtual Weapon getWeapon();

virtual void setWeapon(Weapon w);

virtual Weapon getArmor();

virtual void setArmor(Weapon a);

virtual unsigned getLevel();

virtual void setLevel(unsigned amt);

virtual double getHealth();

virtual void setHealth(double amt);

virtual double getXP();

virtual void setXP(double amt);

Person();

Person(string n);

private:

Weapon wep;

Weapon armor;

double xp;

unsigned level;

double health;

unsigned x;

unsigned y;

};





class Weapon {

public:

double getStrength();

void setStrength(double s);

double getValue();

void setValue(double amt);

double getHealth();

void setHealth(double amt);

string getName();

void setName(string n);

string getType();

void setType(string t);

Weapon();

Weapon(string n, string t, double dmg);

private:

string name;

string type;

double value;

double health;

double strength;

};

Your error boils down to the One Definition Rule (ODR) and the requirements that the language places on programs. In particular the requirement that every function that is used must be defined. A non-virtual function is considered odr-used if it is called, or it's address is taken. All virtual functions are odr-used and thus must be defined in your program.

Going back to the exact error in your program, it is probably due to how the GCC compiler deals with the generation of the virtual tables, which basically boils down to a simple rule: the virtual table is defined in the translation unit that holds the definition of the first non-inline virtual function in the class. If all virtual functions are inline, then the vtable will be generated in each and all translation units that include the definition of the class.

It seems that in your case, there is at least one virtual function that is not declared inline or defined in one of the translation units that get linked in the program. If the first non-inline virtual function was defined in one of the translation units, then the vtable would have been generated, and you would get a different error message regarding the lack of definition of any of the virtual functions for which there is no definition.

It's saying that there are virtual fields in Person which are not defined. So far we can see your declarations, but not definitions. Check that every virtual field in Person, including those inherited, is defined.