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typedef support for Unreal Header Tool

Simple request, this won’t compile because UHT doesn’t recognise the type.



typedef uint8 TeamID;

UPROPERTY()
TeamID MyTeam;

UFUNCTION(BlueprintCallable)
void MyFunction(TeamID InTeam);


There’s not really any logical reason why this shouldn’t work, and surely it should be fairly trivial to allow UHT to check if a typedef is a supported type for reflection?

You can’t use #define either, as it turns out :frowning:



#define TeamID uint8

UPROPERTY()
TeamID MyTeam;

UFUNCTION(BlueprintCallable)
void MyFunction(TeamID InTeam);


Instead, I have to use a struct. This seems overly complex:



USTRUCT(BlueprintType)
struct FTeamID
{
	GENERATED_BODY()

public:
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Team")
	uint8 TeamID;

	FTeamID()
		: TeamID(0)
	{}

	FTeamID(const uint8 InTeamID)
		: TeamID(InTeamID)
	{}

	FORCEINLINE bool operator==(const FTeamID& Other) const
	{
		return TeamID == Other.TeamID;
	}

	FORCEINLINE bool operator!=(const FTeamID& Other) const
	{
		return TeamID != Other.TeamID;
	}

	FORCEINLINE bool operator>=(const FTeamID& Other) const
	{
		return TeamID >= Other.TeamID;
	}

	FORCEINLINE bool operator>(const FTeamID& Other) const
	{
		return TeamID > Other.TeamID;
	}

	FORCEINLINE bool operator<=(const FTeamID& Other) const
	{
		return TeamID <= Other.TeamID;
	}

	FORCEINLINE bool operator<(const FTeamID& Other) const
	{
		return TeamID < Other.TeamID;
	}
};

UPROPERTY()
TeamID MyTeam;

UFUNCTION(BlueprintCallable)
void MyFunction(TeamID InTeam);


I’m just going to bump this since it still does not work at least on my end.

It isn’t easy to do this unfortunately and I doubt they Epic will add this ever. #define will never be added to UHT as it is way to complex due to you being able to include #define instead #define.

Yeah, at the time I vastly underestimated just how difficult this is. I don’t think this will ever be supported.

I’m curious, what approach did you end up taking @TheJamsh? I’m doing some periodic calculations necessary for the Vision system in an RTS game, so I opted for Bit field operations. I wanted to use replication though, and that’s when I hit the wall of typedef uint32 PlayersMask not supported by UHT.

Should I do something similar to your alternative?


struct FPlayersMask

Is there a better approach suggested? I’m concerned about the performance cost of introducing a whole struct where I really want speed (hence the Bitwise operations in the first place)

This was years ago so I’m not sure, but now I just use structs for this kind of thing and wrap with USTRUCT(), then create operator overloads if I need to.

A struct doesn’t cost anything more than the sum of it’s types in terms of memory and replication cost etc. If anything you can benefit from using a USTRUCT() because you can write your own network serialization code via NetSerialize() etc.