@@ -15,12 +15,10 @@
 
 #import "OFObject.h"
 
 OF_ASSUME_NONNULL_BEGIN
 
-#define OF_SERIALIZATION_NS @"https://objfw.nil.im/serialization"
-
 @class OFXMLElement;
 
 /**
  * @protocol OFSerialization OFSerialization.h ObjFW/OFSerialization.h
  *
@@ -38,7 +36,15 @@
  * @param element An OFXMLElement with the serialized object
  * @return An initialized object
  */
 - (instancetype)initWithSerialization: (OFXMLElement *)element;
 @end
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+extern OFString *const OFSerializationNS;
+#ifdef __cplusplus
+}
+#endif
 
 OF_ASSUME_NONNULL_END