Fatal error LNK1120 and LNK2019

Development Programming & Scripting
1

I have the errors LNK2019 and LNK1120 when I build my C++ BlueprintFuctionLibrary. I don’t know how to fix these errors and hope, that someone can help me.

MyBlueprintFunctionLibrary.h :
#pragma once

#include "Sockets.h"
#include "Networking.h"
#include "Kismet/BlueprintFunctionLibrary.h"
#include "MyBlueprintFunctionLibrary.generated.h"

/**
 * 
 */
UCLASS()
class INVENTORY_API UMyBlueprintFunctionLibrary : public UBlueprintFunctionLibrary
{
	GENERATED_BODY()
public:
		
		UFUNCTION(BlueprintPure, Category = "Network")
			static bool sendStringToServer(FString adress, int32 port, FString Text);
		
};

MyBlueprintFunctionLibrary.cpp :

#include "Inventory.h"
#include "Sockets.h"
#include "Networking.h"
#include "MyBlueprintFunctionLibrary.h"





bool sendStringToServer(FString adress, int32 port, FString Text) {

	FSocket* Socket = ISocketSubsystem::Get(PLATFORM_SOCKETSUBSYSTEM)->CreateSocket(NAME_Stream, TEXT("default"), false);
	FIPv4Address  ip;
	FIPv4Address::Parse(adress,ip);
	TSharedRef<FInternetAddr> addr = ISocketSubsystem::Get(PLATFORM_SOCKETSUBSYSTEM)->CreateInternetAddr();
	addr->SetIp(ip.GetValue());
	addr->SetPort(port);

	bool connected = Socket->Connect(*addr);

	TCHAR *serializedChar = Text.GetCharArray().GetData();
	int32 size = FCString::Strlen(serializedChar);
	int32 sent = 0;

	bool successful = Socket->Send((uint8*)TCHAR_TO_UTF8(serializedChar), size, sent);
	return successful;
}

Build.cs :

using UnrealBuildTool;

public class Inventory : ModuleRules
{
	public Inventory(TargetInfo Target)
	{
		PublicDependencyModuleNames.AddRange(new string[] { "Core", "CoreUObject", "Engine", "InputCore" ,"Networking","Sockets"});

		PrivateDependencyModuleNames.AddRange(new string[] {  });

		// Uncomment if you are using Slate UI
		// PrivateDependencyModuleNames.AddRange(new string[] { "Slate", "SlateCore" });
		
		// Uncomment if you are using online features
		// PrivateDependencyModuleNames.Add("OnlineSubsystem");
		// if ((Target.Platform == UnrealTargetPlatform.Win32) || (Target.Platform == UnrealTargetPlatform.Win64))
		// {
		//		if (UEBuildConfiguration.bCompileSteamOSS == true)
		//		{
		//			DynamicallyLoadedModuleNames.Add("OnlineSubsystemSteam");
		//		}
		// }
	}
}

Error Message:

MyBlueprintFunctionLibrary.cpp.obj : error LNK2019: unresolved external symbol “public: static bool __cdecl UMyBlueprintFunctionLibrary::sendStringToServer(class FString,int,class FString)” (?sendStringToServer@UMyBlueprintFunctionLibrary@@SA_NVFString@@H0@Z) referenced in function “public: void __cdecl UMyBlueprintFunctionLibrary::execsendStringToServer(struct FFrame &,void * const)” (?execsendStringToServer@UMyBlueprintFunctionLibrary@@QEAAXAEAUFFrame@@QEAX@Z)
1>Inventory.generated.cpp.obj : error LNK2001: unresolved external symbol “public: static bool __cdecl UMyBlueprintFunctionLibrary::sendStringToServer(class FString,int,class FString)” (?sendStringToServer@UMyBlueprintFunctionLibrary@@SA_NVFString@@H0@Z)
1>C:\Users\Julian\Documents\Unreal Projects\Inventory\Binaries\Win64\UE4Editor-Inventory-5300.dll : fatal error LNK1120: 1 unresolved externals

1 Like
2

You’re getting the unresolved external symbol because you haven’t defined UMyBlueprintFunctionLibrary::sendStringToServer anywhere. You may think you have, but in your .cpp file your definition of sendStringToServer is missing UMyBlueprintFunctionLibrary:: prefix.

3 Likes