diff --git a/ndn-cpp/c/encoding/BinaryXMLEncoder.h b/ndn-cpp/c/encoding/BinaryXMLEncoder.h
index 98dc13f..7d097ee 100644
--- a/ndn-cpp/c/encoding/BinaryXMLEncoder.h
+++ b/ndn-cpp/c/encoding/BinaryXMLEncoder.h
@@ -99,7 +99,7 @@
   if (value && valueLength > 0)
     return ndn_BinaryXMLEncoder_writeBlobDTagElement(self, tag, value, valueLength);
   else
-    return 0;
+    return (ndn_Error)0;
 }
 
 /**
@@ -133,7 +133,7 @@
   if (value >= 0)
     return ndn_BinaryXMLEncoder_writeUnsignedDecimalIntDTagElement(self, tag, (unsigned int)value);
   else
-    return 0;
+    return (ndn_Error)0;
 }
 
 /**