Linker errors, i don't understand a single piece of it!

[lillecarl]

Im trying to create a "Pet Creator NPC", so i got this code piece here: (Stolen from Spelleffects.cpp with a few edits so it compiles)

bool GossipSelect_beast_master(Player *pPlayer, Creature *pCreature, uint32 sender, uint32 action)
{	
if (pPlayer->getClass() == CLASS_HUNTER)
{
	ChatHandler(pPlayer->GetSession()).PSendSysMessage("Right after if (pPlayer->getClass() == CLASS_HUNTER)");
	Creature *creatureTarget = ChatHandler(pPlayer->GetSession()).getSelectedCreature();

	Pet* pPet = new Pet(HUNTER_PET);

	if(!pPet->CreateBaseAtCreature(creatureTarget))
	{
		delete pPet;
		return false;
	}

	pPet->SetOwnerGuid(pPlayer->GetObjectGuid());
	pPet->SetCreatorGuid(pPlayer->GetObjectGuid());
	pPet->setFaction(pPlayer->getFaction());
	pPet->SetUInt32Value(UNIT_CREATED_BY_SPELL, 13481);

	if (pPlayer->IsPvP())
		pPet->SetPvP(true);

	if (!pPet->InitStatsForLevel(creatureTarget->getLevel()))
	{
		sLog.outError("Pet::InitStatsForLevel() failed for creature (Entry: %u)!",creatureTarget->GetEntry());
		delete pPet;
		return false;
	}

	pPet->GetCharmInfo()->SetPetNumber(sObjectMgr.GeneratePetNumber(), true);
	// this enables pet details window (Shift+P)
	pPet->AIM_Initialize();
	pPet->InitPetCreateSpells();
	pPet->SetHealth(pPet->GetMaxHealth());

	// "kill" original creature
	creatureTarget->ForcedDespawn();

	// prepare visual effect for levelup
	pPet->SetUInt32Value(UNIT_FIELD_LEVEL,creatureTarget->getLevel()-1);

	// add to world
	pPet->GetMap()->Add((Creature*)pPet);

	// visual effect for levelup
	pPet->SetUInt32Value(UNIT_FIELD_LEVEL,creatureTarget->getLevel());

	// caster have pet now
	pPlayer->SetPet(pPet);

	pPet->SavePetToDB(PET_SAVE_AS_CURRENT);
	pPlayer->PetSpellInitialize();
}
return true;
}

And when i try to compile it, i get this linker errors:

1>npc_scripts.obj : error LNK2019: unresolved external symbol "public: void __thiscall Map::Add<class Creature>(class Creature *)" (??$Add@VCreature@@@Map@@QAEXPAVCreature@@@Z) referenced in function "bool __cdecl GossipSelect_beast_master(class Player *,class Creature *,unsigned int,unsigned int)" (?GossipSelect_beast_master@@YA_NPAVPlayer@@PAVCreature@@II@Z)

1>npc_scripts.obj : error LNK2019: unresolved external symbol "public: void __thiscall CharmInfo::SetPetNumber(unsigned int,bool)" (?SetPetNumber@CharmInfo@@QAEXI_N@Z) referenced in function "bool __cdecl GossipSelect_beast_master(class Player *,class Creature *,unsigned int,unsigned int)" (?GossipSelect_beast_master@@YA_NPAVPlayer@@PAVCreature@@II@Z)

1>npc_scripts.obj : error LNK2019: unresolved external symbol "public: void __cdecl Log::outError(char const *,...)" (?outError@Log@@QAAXPBDZZ) referenced in function "bool __cdecl GossipSelect_beast_master(class Player *,class Creature *,unsigned int,unsigned int)" (?GossipSelect_beast_master@@YA_NPAVPlayer@@PAVCreature@@II@Z)

1>npc_scripts.obj : error LNK2019: unresolved external symbol "public: unsigned int __thiscall IdGenerator<unsigned int>::Generate(void)" (?Generate@?$IdGenerator@I@@QAEIXZ) referenced in function "public: unsigned int __thiscall ObjectMgr::GeneratePetNumber(void)" (?GeneratePetNumber@ObjectMgr@@QAEIXZ)

1>npc_scripts.obj : error LNK2001: unresolved external symbol "private: static bool MaNGOS::Singleton<class ObjectMgr,class MaNGOS::SingleThreaded<class ObjectMgr>,class MaNGOS::OperatorNew<class ObjectMgr>,class MaNGOS::ObjectLifeTime<class ObjectMgr> >::si_destroyed" (?si_destroyed@?$Singleton@VObjectMgr@@V?$SingleThreaded@VObjectMgr@@@MaNGOS@@V?$OperatorNew@VObjectMgr@@@3@V?$ObjectLifeTime@VObjectMgr@@@3@@MaNGOS@@0_NA)

1>npc_scripts.obj : error LNK2001: unresolved external symbol "private: static class ObjectMgr * MaNGOS::Singleton<class ObjectMgr,class MaNGOS::SingleThreaded<class ObjectMgr>,class MaNGOS::OperatorNew<class ObjectMgr>,class MaNGOS::ObjectLifeTime<class ObjectMgr> >::si_instance" (?si_instance@?$Singleton@VObjectMgr@@V?$SingleThreaded@VObjectMgr@@@MaNGOS@@V?$OperatorNew@VObjectMgr@@@3@V?$ObjectLifeTime@VObjectMgr@@@3@@MaNGOS@@0PAVObjectMgr@@A)

1>npc_scripts.obj : error LNK2019: unresolved external symbol "public: __thiscall ObjectMgr::ObjectMgr(void)" (??0ObjectMgr@@QAE@XZ) referenced in function "public: static class ObjectMgr * __cdecl MaNGOS::OperatorNew<class ObjectMgr>::Create(void)" (?Create@?$OperatorNew@VObjectMgr@@@MaNGOS@@SAPAVObjectMgr@@XZ)

1>npc_scripts.obj : error LNK2019: unresolved external symbol "public: __thiscall ObjectMgr::~ObjectMgr(void)" (??1ObjectMgr@@QAE@XZ) referenced in function "public: void * __thiscall ObjectMgr::`scalar deleting destructor'(unsigned int)" (??_GObjectMgr@@QAEPAXI@Z)

1>npc_scripts.obj : error LNK2001: unresolved external symbol "private: static bool MaNGOS::Singleton<class Log,class MaNGOS::SingleThreaded<class Log>,class MaNGOS::OperatorNew<class Log>,class MaNGOS::ObjectLifeTime<class Log> >::si_destroyed" (?si_destroyed@?$Singleton@VLog@@V?$SingleThreaded@VLog@@@MaNGOS@@V?$OperatorNew@VLog@@@3@V?$ObjectLifeTime@VLog@@@3@@MaNGOS@@0_NA)

1>npc_scripts.obj : error LNK2001: unresolved external symbol "private: static class Log * MaNGOS::Singleton<class Log,class MaNGOS::SingleThreaded<class Log>,class MaNGOS::OperatorNew<class Log>,class MaNGOS::ObjectLifeTime<class Log> >::si_instance" (?si_instance@?$Singleton@VLog@@V?$SingleThreaded@VLog@@@MaNGOS@@V?$OperatorNew@VLog@@@3@V?$ObjectLifeTime@VLog@@@3@@MaNGOS@@0PAVLog@@A)

1>npc_scripts.obj : error LNK2019: unresolved external symbol "private: __thiscall Log::Log(void)" (??0Log@@AAE@XZ) referenced in function "public: static class Log * __cdecl MaNGOS::OperatorNew<class Log>::Create(void)" (?Create@?$OperatorNew@VLog@@@MaNGOS@@SAPAVLog@@XZ)

1>..\\..\\..\\..\\bin\\win32_release/mangosscript.dll : fatal error LNK1120: 11 unresolved externals

And the sad part about this is that, however much i read on MSDN and forums, i do not understand anything! I would atleast want a hint in the correct direction, because i really wanna learn how you fix those linker errors, they have been a mess before. I mean the outlog calls can just be removed, but adding the pet to the world etc.. is pretty much needed.

EDIT: Solved a few now by changing:

struct CharmInfo
into
struct MANGOS_DLL_SPEC CharmInfo

EDIT2: Solved even another by changing:

class IdGenerator
into
class MANGOS_DLL_SPEC IdGenerator


Those left:

1>npc_scripts.obj : error LNK2019: unresolved external symbol "public: void __thiscall Map::Add<class Creature>(class Creature *)" (??$Add@VCreature@@@Map@@QAEXPAVCreature@@@Z) referenced in function "bool __cdecl GossipSelect_beast_master(class Player *,class Creature *,unsigned int,unsigned int)" (?GossipSelect_beast_master@@YA_NPAVPlayer@@PAVCreature@@II@Z)
1>npc_scripts.obj : error LNK2001: unresolved external symbol "private: static bool MaNGOS::Singleton<class ObjectMgr,class MaNGOS::SingleThreaded<class ObjectMgr>,class MaNGOS::OperatorNew<class ObjectMgr>,class MaNGOS::ObjectLifeTime<class ObjectMgr> >::si_destroyed" (?si_destroyed@?$Singleton@VObjectMgr@@V?$SingleThreaded@VObjectMgr@@@MaNGOS@@V?$OperatorNew@VObjectMgr@@@3@V?$ObjectLifeTime@VObjectMgr@@@3@@MaNGOS@@0_NA)
1>npc_scripts.obj : error LNK2001: unresolved external symbol "private: static class ObjectMgr * MaNGOS::Singleton<class ObjectMgr,class MaNGOS::SingleThreaded<class ObjectMgr>,class MaNGOS::OperatorNew<class ObjectMgr>,class MaNGOS::ObjectLifeTime<class ObjectMgr> >::si_instance" (?si_instance@?$Singleton@VObjectMgr@@V?$SingleThreaded@VObjectMgr@@@MaNGOS@@V?$OperatorNew@VObjectMgr@@@3@V?$ObjectLifeTime@VObjectMgr@@@3@@MaNGOS@@0PAVObjectMgr@@A)
1>npc_scripts.obj : error LNK2019: unresolved external symbol "public: __thiscall ObjectMgr::ObjectMgr(void)" (??0ObjectMgr@@QAE@XZ) referenced in function "public: static class ObjectMgr * __cdecl MaNGOS::OperatorNew<class ObjectMgr>::Create(void)" (?Create@?$OperatorNew@VObjectMgr@@@MaNGOS@@SAPAVObjectMgr@@XZ)
1>npc_scripts.obj : error LNK2019: unresolved external symbol "public: __thiscall ObjectMgr::~ObjectMgr(void)" (??1ObjectMgr@@QAE@XZ) referenced in function "public: void * __thiscall ObjectMgr::`scalar deleting destructor'(unsigned int)" (??_GObjectMgr@@QAEPAXI@Z)
1>..\\..\\..\\..\\bin\\win32_release/mangosscript.dll : fatal error LNK1120: 5 unresolved externals

EDIT: I fixed it by creating a function in player.cpp containing the code instead and call it from the script, it works. But it surely is not the "correct way" in my opinion, so i would like to know how you fix the linker errors still =)

Thanks in advance

- Carl

[faramir118]

You found the correct solution; add a declaration in the header (.h), definition in the source (.cpp)

[lillecarl]

Ah i think i got it =)