HRESULT XStoreGetUserPurchaseIdAsync(  
         const XStoreContextHandle storeContextHandle,  
         const char* serviceTicket,  
         const char* publisherUserId,  
         XAsyncBlock* async  
)  

void CALLBACK GetUserPurchaseIdCallback(XAsyncBlock* asyncBlock)
{
    size_t size;
    HRESULT hr = XStoreGetUserPurchaseIdResultSize(
        asyncBlock,
        &size);

    if (FAILED(hr))
    {
        printf("Failed retrieve the user purchase ID size: 0x%x\r\n", hr);
        return;
    }

    char* result = new char[size];
    hr = XStoreGetUserPurchaseIdResult(
        asyncBlock,
        size,
        result);

    if (FAILED(hr))
    {
        printf("Failed retrieve the user purchase ID result: 0x%x\r\n", hr);
        delete[] result;
        return;
    }

    printf("result: %s\r\n", result);

    delete[] result;
}

void GetUserPurchaseId(XStoreContextHandle storeContextHandle, XTaskQueueHandle taskQueueHandle, const char* serviceTicket, const char* publisherUserId)
{
    auto asyncBlock = std::make_unique<XAsyncBlock>();
    ZeroMemory(asyncBlock.get(), sizeof(*asyncBlock));
    asyncBlock->queue = taskQueueHandle;

    asyncBlock->callback = GetUserPurchaseIdCallback;

    HRESULT hr = XStoreGetUserPurchaseIdAsync(
        storeContextHandle,
        serviceTicket,
        publisherUserId,
        asyncBlock.get());

    if (FAILED(hr))
    {
        printf("Failed to get user purchase ID: 0x%x\r\n", hr);
        return;
    }
}