Error with JSON when compile C++ in Windows.

[anonymous_user_4e40effd]

Hi, I need help with an error in Unreal Engine 16.2 when I compile C++ with JSON.

I compiled the same project with Unreal Engine 16.2 in Gnu/Linux OS but when I compile in Windows I get error on all Json actions.

So, I commented all the lines as they have the same error except one.

TSharedPtr< FJsonObject > JsonObj = MakeShareable(new FJsonObject);

The error is:

CompilerResultsLog:Error: Error Socket.cpp.obj : error LNK2019: unresolved external symbol “__declspec(dllimport) public: __cdecl FJsonObject::FJsonObject(void)” (_imp??0FJsonObject@@QEAA@XZ) referenced in function “public: class FString __cdecl FControlStruct::getJsonString(void)” (?getJsonString@FControlStruct@@QEAA?AVFString@@XZ)
CompilerResultsLog:Error: Error Socket.cpp.obj : error LNK2019: unresolved external symbol “__declspec(dllimport) public: __cdecl FJsonObject::~FJsonObject(void)” (_imp??1FJsonObject@@QEAA@XZ) referenced in function “public: virtual void __cdecl SharedPointerInternals::TReferenceControllerWithDeleter<class FJsonObject,struct SharedPointerInternals::Default
Deleter<class FJsonObject> >::DestroyObject(void)” (?DestroyObject@?$TReferenceControllerWithDeleter@VFJsonObject@@U?$DefaultDeleter@VFJsonObject@@@SharedPointerInternals@@@SharedPointerInternals@@UEAAXXZ)
CompilerResultsLog:Error: Error C:\Users\Leandro\Documents\Unreal Projects\RaspDrone_Client\Binaries\Win64\UE4Editor-RaspDrone_Client-4500.dll : fatal error LNK1120: 2 unresolved externals
CompilerResultsLog: Información ERROR: UBT ERROR: Failed to produce item: C:\Users\Leandro\Documents\Unreal Projects\RaspDrone_Client\Binaries\Win64\UE4Editor-RaspDrone_Client-4500.dll

any idea?, thanx! and regards.

[mittense]

In order for that to compile you need to do one of these:

TSharedRef< FJsonObject > JsonObj = MakeShareable(new FJsonObject);

or

TSharedPtr< FJsonObject > JsonObj = MakeShareable(new FJsonObject( ));

The semantics of C++ are lovely, aren’t they

[anonymous_user_4e40effd]

Hi mittense, thank you for your reply.

I was able to solve the problem and the solution is to add modules in the build.cs
In my case, I added a line with Json and JsonUtilities.

PublicDependencyModuleNames.AddRange(new string] { “Json”, “JsonUtilities” });

But, I don’t understand why in Linux is not necessary.

Regards!

[ANLevant]

2020 this stuff saved my life. Thank you !