HRESULT XStoreQueryLicenseTokenAsync(  
         const XStoreContextHandle storeContextHandle,  
         const char** productIds,  
         size_t productIdsCount,  
         const char* customDeveloperString,  
         XAsyncBlock* async  
)  

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

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

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

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

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

    delete[] result;
}

void QueryLicenseToken(XStoreContextHandle storeContextHandle, XTaskQueueHandle taskQueueHandle, const char** productIds, size_t productIdsCount, const char* customDeveloperString)
{
    auto asyncBlock = std::make_unique<XAsyncBlock>();
    ZeroMemory(asyncBlock.get(), sizeof(*asyncBlock));
    asyncBlock->queue = taskQueueHandle;
    asyncBlock->callback = QueryLicenseTokenCallback;

    HRESULT hr = XStoreQueryLicenseTokenAsync(
        storeContextHandle,
        productIds,
        productIdsCount,
        customDeveloperString,
        asyncBlock.get());

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