diff --git a/src/printutils.h b/src/printutils.h
index 971a6211..8fd0caee 100644
--- a/src/printutils.h
+++ b/src/printutils.h
@@ -12,7 +12,10 @@ inline char * _( const char * msgid ) { return gettext( msgid ); }
 typedef void (OutputHandlerFunc)(const std::string &msg, void *userdata);
 extern OutputHandlerFunc *outputhandler;
 extern void *outputhandler_data;
-namespace OpenSCAD { extern std::string debug; }
+namespace OpenSCAD {
+	extern std::string debug;
+	extern bool quiet;
+}
 
 void set_output_handler(OutputHandlerFunc *newhandler, void *userdata);