I've been implementing in app purchases into an existing C++ app. I'm using the latest Swift StoreKit since the old ObjC interface is deprecated . There is a really weird problem where the swift/C++ bridging seems to get into a loop. After the Product structure is retrieved I have the following structure which I use to bridge to C++ public struct storeData { public var id : String public var displayName : String public var description : String public var price : String public var purchased : Bool = false public var level : Int = 0 } and this is passed back to the caller as follows public func getProducts (bridge : StoreBridge) -> [storeData] { bridge.products.sort { $0.price > $1.price } var productList : [storeData] = [] for product in bridge.products { let data : storeData = storeData(id: product.id, displayName: product.displayName, description: product.description, price: product.displayPrice, purchased: bridge.purchasedProductIds.contains(product.id) ) productList.append(data) } return productList } the "bridge" variable is a bridging class where the guts of the bridge resides, and contains the "products" array as a publishable variable. In the C++ code the data is retrieved by outProd->id = String(inProd.getId()); outProd->displayName = String(inProd.getDisplayName()); outProd->description = String(inProd.getDescription()); outProd->price = String(String(inProd.getPrice())); outProd->purchased = inProd.getPurchased(); The "String" is actually a JUCE string but that's not part of the problem. Testing this with a local StoreKit config file works fine but when I test with a sandbox AppStore the app hangs. Very specifically it hangs somewhere in the Swift thunk when retrieving the price. When I remove the line to retrieve the price everything works. And - and this is the weird bit - when I pad the price out with some random text, it now starts working (so I have a workaround). This is, however, slightly worrying behaviour. Ideas?