A Bug in project?

[royalcw]

The instructor doesn’t include:

APawnTurret::APawnTurret()
{
	// Nothing needed in here.
}

However, without that bit, I get this error and can’t compile.

1>PawnTurret.cpp.obj : error LNK2019: unresolved external symbol "public: __cdecl APawnTurret::APawnTurret(void)" (??0APawnTurret@@QEAA@XZ) referenced in function "public: static void __cdecl APawnTurret::__DefaultConstructor(class FObjectInitializer const &)" (?__DefaultConstructor@APawnTurret@@SAXAEBVFObjectInitializer@@@Z)
1>PawnTurret.gen.cpp.obj : error LNK2001: unresolved external symbol "public: __cdecl APawnTurret::APawnTurret(void)" (??0APawnTurret@@QEAA@XZ)
1>D:\Unreal\Projects\ToonTanks\Binaries\Win64\UE4Editor-ToonTanks.dll : fatal error LNK1120: 1 unresolved externals

I only added that bit of code because APawnTank.cpp had it and the error had this bit:
APawnTurret::APawnTurret(void) in the error message above that made me think to add it.

Is that bit needed? Why does the instructors code compile without it?

[DanM]

The lecture commit doesn’t have a constructor declared.

[royalcw]

Without the constructor I kept getting the crash posted above. Works great with the constructor.

[DanM]

By crash do you mean compilation error? Crash would mean a runtime error.

If you don’t declare a constructor the compiler generates one for you. If you do then you must define it. So that compilation error means you declared but didn’t define a constructor.

I’ve checked out this lecture’s commit and it does successfully compile.

[royalcw]

It was a compilation error. Does Visual Studio 2019 not define a constructor or generate one automatically? Didn’t see one in the lectures video so that is why I was wondering why I had to manually add it when it wasn’t in his video. Well, hopefully no one else has the same issue.

[DanM]

@royalcw

Does Visual Studio 2019 not define a constructor or generate one automatically?

It does, it’s a rule of C++ that the compiler automatically generates them if you don’t declare them. If that stopped working in 2019 that would break a lot of people’s code and no one would be using it.

And as I’ve stated I tested the code and it compiles.

[Laurent]

Your first error was probably because you didn’t add the constructor declaration in the .h file whereas the constructor was implemented in the .cpp file