Mark Object instances const
diff --git a/OpenFilesScreen.h b/OpenFilesScreen.h
index 9d63fe7..9a12dcd 100644
--- a/OpenFilesScreen.h
+++ b/OpenFilesScreen.h
@@ -29,7 +29,7 @@
    pid_t pid;
 } OpenFilesScreen;
 
-extern InfoScreenClass OpenFilesScreen_class;
+extern const InfoScreenClass OpenFilesScreen_class;
 
 OpenFilesScreen* OpenFilesScreen_new(Process* process);