extern "C" used in skeletons

diff --git a/skeletons/PrintableString.h b/skeletons/PrintableString.h
index e4a230d..2ece440 100644
--- a/skeletons/PrintableString.h
+++ b/skeletons/PrintableString.h
@@ -7,10 +7,18 @@
 
 #include <OCTET_STRING.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef OCTET_STRING_t PrintableString_t;  /* Implemented via OCTET STRING */
 
 extern asn_TYPE_descriptor_t asn_DEF_PrintableString;
 
 asn_constr_check_f PrintableString_constraint;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif	/* _PrintableString_H_ */