diff --git a/src/common/file_util.h b/src/common/file_util.h
index 880b8a1e3..80e618aca 100644
--- a/src/common/file_util.h
+++ b/src/common/file_util.h
@@ -260,6 +260,7 @@ public:
     // clear error state
     void Clear() { m_good = true; std::clearerr(m_file); }
 
+private:
     std::FILE* m_file;
     bool m_good;
 };