diff --git a/samples/hellovr_opengl/hellovr_opengl_main.cpp b/samples/hellovr_opengl/hellovr_opengl_main.cpp
index 64d1d47..dac2e9f 100644
--- a/samples/hellovr_opengl/hellovr_opengl_main.cpp
+++ b/samples/hellovr_opengl/hellovr_opengl_main.cpp
@@ -1276,6 +1276,12 @@ bool CMainApplication::SetupStereoRenderTargets()
 	return true;
 }
 
+//http://www.g-truc.net/post-0708.html
+template <typename T, std::size_t N>
+constexpr std::size_t _countof(T const (&)[N]) noexcept
+{
+return N;
+}
 
 //-----------------------------------------------------------------------------
 // Purpose: