TTuple is not exposed to blueprints
.h
USTRUCT(Blueprintable)
struct FInventorytStruct
{
GENERATED_BODY();
UPROPERTY(BlueprintReadOnly, VisibleAnywhere)
bool Added;
UPROPERTY(BlueprintReadOnly, VisibleAnywhere)
int32 index;
};
UFUNCTION(BlueprintCallable)
void AddToInvenoty(FName ItemID, int Quantity, FInventorytStruct& outValue);
.cpp
void AMyCharacter::AddToInvenoty(FName ItemID, int Quantity, FInventorytStruct& outValue) {
outValue.Added = true;
outValue.index = 22;
}
(after right clicking spit struct for output)