diff --git a/CHANGES.current b/CHANGES.current
index 6ce431b60..cf57d393e 100644
--- a/CHANGES.current
+++ b/CHANGES.current
@@ -5,6 +5,10 @@ See the RELEASENOTES file for a summary of changes in each release.
 Version 3.0.3 (in progress)
 ===========================
 
+2014-09-01: olly
+	    Issue an error for unknown SWIG preprocessor directives, rather
+	    than quietly ignoring them.  Reported by jrhelsey in issue#217.
+
 2014-08-15: talby
             [Perl] Include guard fix for nested modules from Anthony Heading (SF Patch #350).
 
diff --git a/Source/Preprocessor/cpp.c b/Source/Preprocessor/cpp.c
index baadf7132..1ca549703 100644
--- a/Source/Preprocessor/cpp.c
+++ b/Source/Preprocessor/cpp.c
@@ -1768,6 +1768,8 @@ String *Preprocessor_parse(String *s) {
 	}
       } else if (Equal(id, kpp_level)) {
 	Swig_error(Getfile(s), Getline(id), "cpp debug: level = %d, startlevel = %d\n", level, start_level);
+      } else {
+	Swig_error(Getfile(s), Getline(id), "Unknown SWIG preprocessor directive: %s\n", id);
       }
       for (i = 0; i < cpp_lines; i++)
 	Putc('\n', ns);