Change all C code to return ndn_Error enum instead of char * error string.
diff --git a/ndn-cpp/c/encoding/BinaryXMLInterest.h b/ndn-cpp/c/encoding/BinaryXMLInterest.h
index 12de088..38917aa 100644
--- a/ndn-cpp/c/encoding/BinaryXMLInterest.h
+++ b/ndn-cpp/c/encoding/BinaryXMLInterest.h
@@ -6,15 +6,16 @@
#ifndef NDN_BINARYXMLINTEREST_H
#define NDN_BINARYXMLINTEREST_H
+#include "../errors.h"
#include "../Interest.h"
#ifdef __cplusplus
extern "C" {
#endif
-char *ndn_encodeBinaryXMLInterest(struct ndn_Interest *interest, struct ndn_BinaryXMLEncoder *encoder);
+ndn_Error ndn_encodeBinaryXMLInterest(struct ndn_Interest *interest, struct ndn_BinaryXMLEncoder *encoder);
-char *ndn_decodeBinaryXMLInterest(struct ndn_Interest *interest, struct ndn_BinaryXMLDecoder *decoder);
+ndn_Error ndn_decodeBinaryXMLInterest(struct ndn_Interest *interest, struct ndn_BinaryXMLDecoder *decoder);
#ifdef __cplusplus
}