diff --git a/fpdfsdk/cpdfsdk_annot.h b/fpdfsdk/cpdfsdk_annot.h
index aafd4c8..d930e62 100644
--- a/fpdfsdk/cpdfsdk_annot.h
+++ b/fpdfsdk/cpdfsdk_annot.h
@@ -130,6 +130,7 @@
  protected:
   explicit CPDFSDK_Annot(CPDFSDK_PageView* pPageView);
 
+ private:
   UnownedPtr<CPDFSDK_PageView> const m_pPageView;
 };