Error: 'struct' Can't find struct 'FObjectAndNameAsStringProxyArchive'

Development Programming & Scripting
1

Here’s my code. Not what’s wrong. Or why I’m having such a hard time with structs in general. Like why I can’t just make a c++ struct from the editor. Or having to do something weird.
#pragma once

#include "CoreMinimal.h"
#include "GameFramework/SaveGame.h"
#include "Structs/SaveData.h"
#include "Serialization/ObjectAndNameAsStringProxyArchive.h"
#include "MeatSaveGame.generated.h"

/**
 *
 */
USTRUCT(BlueprintType)
struct FMeatSaveGameArchive : public FObjectAndNameAsStringProxyArchive
{
	GENERATED_BODY()
	FMeatSaveGameArchive(FArchive& InInnerArchive)
		: FObjectAndNameAsStringProxyArchive(InInnerArchive, true)
	{
		ArIsSaveGame = true;
		ArNoDelta = true;
	}
};

/**
 * 
 */
UCLASS(BlueprintType)
class MEAT_API UMeatSaveGame : public USaveGame
{
	GENERATED_BODY()
public:
	UMeatSaveGame();

	UPROPERTY(VisibleAnywhere, Category = Basic)
	uint32 SlotIndex;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Basic)
	FSaveData SaveData;
};
2

Yeah, I can’t use any of the macros like USTRUCT() or GENERATED_BODY() either. So, that means I won’t be able to use it as a uproperty in some other class?

3

But to use it in say, a function. I’d still need to declare the struct yes?

4

I’m not in a position to test at the moment but my gut feeling is:

  • Blueprints don’t like inheritance in struct (unless something has changed since I last checked). Get rid of the USTRUCT(BlueprintType) and replace with USTRUCT(). You might find that just removing USTRUCT altogether is required.
  • GENERATE_BODY should be removed as your constructors are provided
5

I don’t think you’d want to use FMeatSaveGameArchive as a UPROPERTY. I think you linked to this tutorial in an earlier question which shows it being used with MemoryWriter:

http://runedegroot.com/saving-and-loading-actor-data-in-unreal-engine-4/#comments

Basically, you don’t want to have FMeatSaveGameArchive as a member variable of anything, you just use it as part of the serialization / deserialization process.

6

Cool. I wanted to make sure that was the case. Thanks for the responses :slight_smile:

7

Declaring has nothing to do with the USTRUCT or any other property specifiers. You declare the struct just by creating it (Struct declaration - cppreference.com)

The USTRUCT etc exposes the struct to unreal and helps with memory management etc, but the absence of USTRUCT / UCLASS / UFUNCTION doesn’t normally stop you using it as you’d expect within normal C++. So if you wanted to create a FMeatSaveGameArchive variable within a function, you can do so. If you want to pass it around to other functions either as a value type or reference then you can also do that. The only thing you might need to watch out for is memory management.

Basically, think of it like a normal member variable. You don’t have to use UPROPERTY(), but if you don’t then you just need to be a little more careful.