diff --git a/include/ptycon/ptycon_api.h b/include/ptycon/ptycon_api.h
index bdc7bc1..0f8ae91 100644
--- a/include/ptycon/ptycon_api.h
+++ b/include/ptycon/ptycon_api.h
@@ -15,6 +15,13 @@
 #define ptyc_import
 #endif
 
+/* protected visibility */
+#if	defined(__attr_protected__)
+#define ptyc_protected __attr_protected__
+#else
+#define ptyc_protected
+#endif
+
 /* ptyc_api */
 #ifndef PTYC_APP
 #if     defined (PTYC_EXPORT)
@@ -22,7 +29,7 @@
 #elif   defined (PTYC_IMPORT)
 #define ptyc_api ptyc_import
 #elif   defined (PTYC_STATIC)
-#define ptyc_api
+#define ptyc_api ptyc_protected
 #else
 #define ptyc_api
 #endif