diff --git a/Mesh/periodical.cpp b/Mesh/periodical.cpp
index bf91f11e5f8414adc526f9a8fa10b170e598f374..ecb780e86bbbacfc4bffafeb069209a2464a23ec 100644
--- a/Mesh/periodical.cpp
+++ b/Mesh/periodical.cpp
@@ -394,6 +394,6 @@ void voroMetal3D::correspondance(){
   }
 	
   std::ofstream file;
-  file.open("cells.geo",ios::out | ios::app);
+  file.open("cells.geo",std::ios::out | std::ios::app);
   //geofile << "test\n";
 }
\ No newline at end of file