Circular dependency bug on interface?

[Doc.gdi]

Hello all.
I was trying to make any mesh to play videos. With a solver to hold all media players, textures and so on. And all right, even the interface works well until I tried to create a function in the interface that returns a Array with a struct created on other header file. Then it throws that error warning of a circular dependency even when im using foward declaration

I really ran out of ideas

[3dRaven]

Forward Declare Structs???

You can’t forward declare a struct that is used as a non-pointer (since the size of the struct must be known at compile time) and you cannot tag a struct pointer as UPROPERTY, so you must put that struct on a .h file and include it in your header.

[Doc.gdi]

If I didn’t get you wrong this is what you suggested

But it still complaining about foward declaration. I’ll copy here the code of the .h in case is needed to acces more easy

[Doc.gdi]

The code is

VideoMeshSolver.h:

#pragma once

include “CoreMinimal.h”
include “MediaPlayer.h”
include “MediaTexture.h”
//include “VideoMeshInterface.h” //include the interface
include “GameFramework/Actor.h”
include “Kismet/GameplayStatics.h”
include “VideoMeshSolver.generated.h”

USTRUCT(BlueprintType) //STRUCT
struct FVideoSettings
{
GENERATED_BODY()
//variables and stuff
};

UCLASS()
class VIDEOMESH_API AVideoMeshSolver : public AActor, public IVideoMeshInterface
{
GENERATED_BODY()
//variables and stuff
}

VideoMeshInterface.h:

#pragma once

include “CoreMinimal.h”
include “UObject/Interface.h”
include “VideoMeshSolver.h” //include the class with the struct
include “VideoMeshInterface.generated.h”

// This class does not need to be modified.
UINTERFACE(MinimalAPI)
class UVideoMeshInterface : public UInterface
{
GENERATED_BODY()
};

class VIDEOMESH_API IVideoMeshInterface
{
GENERATED_BODY()

UFUNCTION(BlueprintNativeEvent, BlueprintCallable, Category = Video)
TArray getSettings();

}

VideoMeshComponent.h:

#pragma once

include “CoreMinimal.h”
include “Components/SkeletalMeshComponent.h”
include “VideoMeshInterface.h”
include “VideoMeshSolver.h” //include the class and struct
include “VideoSkeletalMeshComponent.generated.h”

UCLASS(ClassGroup = Rendering, meta = (BlueprintSpawnableComponent))
class VIDEOMESH_API UVideoSkeletalMeshComponent : public USkeletalMeshComponent, public IVideoMeshInterface
{
GENERATED_BODY()
//variables and stuff
}

[3dRaven]

Sorry for the delay the copied code pasted the wrong quotation marks and was spewing out compile errors.

Swapped out the _API for my project just replace it with your own.

VideoMeshInterface.h

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"
#include "UObject/Interface.h"
//#include "VideoMeshSolver.h" //include the class with the struct
#include "VideoMeshInterface.generated.h"

// This class does not need to be modified.
UINTERFACE(MinimalAPI)
class UVideoMeshInterface : public UInterface
{
GENERATED_BODY()
};

class CIRCLEDEP_API IVideoMeshInterface
{
    GENERATED_BODY()
public:
    //UFUNCTION(BlueprintNativeEvent, BlueprintCallable, Category = Video)
        TArray<struct FVideoSettings> getSettings();
};

VideoMeshSolver.h

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"
#include "MediaPlayer.h"
#include "MediaTexture.h"
#include "VideoMeshInterface.h" //include the interface
#include "GameFramework/Actor.h"
#include "Kismet/GameplayStatics.h"
#include "VideoMeshSolver.generated.h"

USTRUCT(BlueprintType) //STRUCT
struct FVideoSettings
{
GENERATED_BODY()
//variables and stuff
};

UCLASS()
    class CIRCLEDEP_API AVideoMeshSolver : public AActor, public IVideoMeshInterface
{
    GENERATED_BODY()
        //variables and stuff
        TArray<FVideoSettings> getSettings();
};

VideoSkeletalMeshComponent.h

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"
#include "Components/SkeletalMeshComponent.h"
#include "VideoMeshInterface.h"
#include "VideoMeshSolver.h" //include the class and struct
#include "VideoSkeletalMeshComponent.generated.h"

UCLASS(ClassGroup = Rendering, meta = (BlueprintSpawnableComponent))
class CIRCLEDEP_API UVideoSkeletalMeshComponent : public USkeletalMeshComponent, public IVideoMeshInterface
{
GENERATED_BODY()
    //variables and stuff
    TArray<FVideoSettings> getSettings();
};

For future projects it’s better to isolate the struct to it’s own file.