diff --git a/include/common.hpp b/include/common.hpp
index 5aa5bfa3..08b3e776 100644
--- a/include/common.hpp
+++ b/include/common.hpp
@@ -19,7 +19,7 @@
 namespace rack {
 
 
-/** Deprecation notice for functions
+/** Attribute for deprecated functions and symbols.
 E.g.
 
 	DEPRECATED void foo();
@@ -30,6 +30,10 @@ E.g.
 	#define DEPRECATED __declspec(deprecated)
 #endif
 
+/** Attribute for private functions and symbols not intended to be used by plugins.
+By default this does nothing, but when #including rack.hpp, it prints a compile-time warning.
+*/
+#define PRIVATE
 
 
 /** Concatenates two literals or two macros
diff --git a/include/rack.hpp b/include/rack.hpp
index 506c42a8..3c9bbd58 100644
--- a/include/rack.hpp
+++ b/include/rack.hpp
@@ -99,6 +99,10 @@
 #include <simd/functions.hpp>
 
 
+#undef PRIVATE
+#define PRIVATE __attribute__ ((warning ("Using private function or symbol")))
+
+
 namespace rack {