diff --git a/example/Vulkan/VK.h b/example/Vulkan/VK.h
index be3f3836..6db8151d 100644
--- a/example/Vulkan/VK.h
+++ b/example/Vulkan/VK.h
@@ -8,8 +8,11 @@
 #define VK_NAMESPACE_BEGIN  namespace hgl{namespace graph{namespace vulkan{
 #define VK_NAMESPACE_END    }}}
 
+VK_NAMESPACE_BEGIN  
 using CharPointerList=hgl::List<const char *>;
 
+uint32_t GetStrideForFormat(const VkFormat &);
+
 inline void debug_out(const hgl::List<VkLayerProperties> &layer_properties)
 {
     const int property_count=layer_properties.GetCount();
@@ -38,5 +41,5 @@ inline void debug_out(const hgl::List<VkExtensionProperties> &extension_properti
         ++ep;
     }
 }
-
+VK_NAMESPACE_END
 #endif//HGL_GRAPH_VULKAN_INCLUDE