Error LNK2005, LNK2001, LNK2019 from replicated function

Development Programming & Scripting
1

I have been trying to replicate functions but these errors keep occurring I have #included

MyCharacter.gen.cpp.obj : error LNK2005: “public: void __cdecl AMyCharacter::HandleFire(void)” (?HandleFire@AMyCharacter@@QEAAXXZ) already defined in MyCharacter.cpp.obj

and

MyCharacter.cpp.obj : error LNK2001: unresolved external symbol “public: virtual void __cdecl AMyCharacter::HandleFire_Implementation(void)” (?HandleFire_Implementation@AMyCharacter@@UEAAXXZ)

and

MyCharacter.cpp.obj : error LNK2019: unresolved external symbol “public: __cdecl AMyCharacter::AMyCharacter(class FObjectInitializer const &)” (??0AMyCharacter@@QEAA@AEBVFObjectInitializer@@@Z) referenced in function “public: static void __cdecl AMyCharacter::__DefaultConstructor(class FObjectInitializer const &)” (?__DefaultConstructor@AMyCharacter@@SAXAEBVFObjectInitializer@@@Z)

please help me I have had this error for a week now

###character.h
FTimerHandle FiringTimer;

 UPROPERTY(EditDefaultsOnly, Category = "Gameplay")
 float FireRate;

 bool bIsFiringWeapon;

 UFUNCTION(BlueprintCallable, Category = "Gameplay")
 void StartFire();

 UFUNCTION(BlueprintCallable, Category = "Gameplay")
 void StopFire();

 UFUNCTION(Server, Reliable)
 void HandleFire();

###character.cpp
void AMyCharacter::StartFire()
{
if (!bIsFiringWeapon)
{
bIsFiringWeapon = true;
UWorld* World = GetWorld();
World->GetTimerManager().SetTimer(FiringTimer, this, &AMyCharacter::StopFire, FireRate, false);
HandleFire();
}
}

  void AMyCharacter::StopFire()
   {
        bIsFiringWeapon = false;
   }

   void AMyCharacter::HandleFire()
   {
         FVector spawnLocation = GetActorLocation() + (GetControlRotation().Vector()  * 100.0f) + (GetActorUpVector() * 50.0f);
          FRotator spawnRotation = GetControlRotation();

          FActorSpawnParameters spawnParameters;
          spawnParameters.Instigator = Instigator;
          spawnParameters.Owner = this;
    }
2

If you have a function in your C++ header file called “Blah”, and it’s hooked up to Unreal via macros like BlueprintCallable, then you need to call it Blah_Implementation in the .CPP file.

Why? When in vanilla C++ you’d just call it MyClass::Blah and call it a day? Because Unreal actually implements a function called MyClass::Blah behind the scenes for you that hides the fact that you’re calling into Blueprint or sending a network RPC, and you can just call myClass->Blah() transparently, as if all that functionality were a natural part of a C++ program, without having to think about those details. It’s a design decision basically.

Ultimately what this compiler error is saying is that you declared a function called MyClass::Blah, and then implemented it twice (Unreal created an implementation for you and then you created a second one), which is bad because the compiler only expects it to be defined once. The other error basically means that Unreal declared a function called Blah_Implementation but you didn’t actually define that function in a .cpp file. (Technically this kind of error is called a Linker Error, which is why the error ID starts with LNK. The linker is the last stage of a C++ compiler where it tries to link everything that’s been compiled together, which is where it notices if something has been defined twice or declared but never defined)

3

thanks that cleared things but The UFUNCTION(Serer, Reliable) void HandleFire() gets a green line underneath asking ist definition is not found when I put _Implementation on its definition and gives me fatal LNK2019