diff --git a/example/Vulkan/VK.h b/example/Vulkan/VK.h
index 67391505..b3ab849b 100644
--- a/example/Vulkan/VK.h
+++ b/example/Vulkan/VK.h
@@ -11,6 +11,10 @@
 VK_NAMESPACE_BEGIN  
 using CharPointerList=hgl::List<const char *>;
 
+#ifdef _DEBUG
+bool CheckStrideBytesByFormat();
+#endif//_DEBUG
+
 uint32_t GetStrideByFormat(const VkFormat &);
 
 inline void debug_out(const hgl::List<VkLayerProperties> &layer_properties)
diff --git a/example/Vulkan/main.cpp b/example/Vulkan/main.cpp
index f3ef697d..73c6d1b8 100644
--- a/example/Vulkan/main.cpp
+++ b/example/Vulkan/main.cpp
@@ -62,12 +62,6 @@ bool LoadShader(VkDevice device)
     return(true);
 }
 
-#ifdef _DEBUG
-VK_NAMESPACE_BEGIN
-bool CheckStrideBytesByFormat();
-VK_NAMESPACE_END
-#endif//
-
 int main(int,char **)
 {
     #ifdef _DEBUG