Test error name is non-empty for the whole range
diff --git a/tinyxml2.cpp b/tinyxml2.cpp
index 667170f..286827a 100755
--- a/tinyxml2.cpp
+++ b/tinyxml2.cpp
@@ -1964,7 +1964,9 @@
 const char* XMLDocument::ErrorName() const

 {

 	TIXMLASSERT( _errorID >= 0 && _errorID < XML_ERROR_COUNT );

-	return _errorNames[_errorID];

+    const char* errorName = _errorNames[_errorID];

+    TIXMLASSERT( errorName && errorName[0] );

+    return errorName;

 }

 

 void XMLDocument::PrintError() const