diff --git a/expat/xmlparse/xmlparse.c b/expat/xmlparse/xmlparse.c
index e7391e4e..8ea54551 100755
--- a/expat/xmlparse/xmlparse.c
+++ b/expat/xmlparse/xmlparse.c
@@ -470,7 +470,7 @@ XML_Parser XML_ParserCreateNS(const XML_Char *encodingName, XML_Char nsSep)
 
 int XML_SetEncoding(XML_Parser parser, const XML_Char *encodingName)
 {
-  if (encodingName)
+  if (!encodingName)
     protocolEncodingName = 0;
   else {
     protocolEncodingName = poolCopyString(&tempPool, encodingName);