diff --git a/src/util/XMLString.cpp b/src/util/XMLString.cpp
index 2444f8d2c638c4914698aba610fb2d97235ca8b3..8be74d5e487048f41c34b727b1e038a5ab50edbb 100644
--- a/src/util/XMLString.cpp
+++ b/src/util/XMLString.cpp
@@ -1478,7 +1478,7 @@ bool XMLString::isWSCollapsed(const XMLCh* const toCheck)
     const XMLCh* startPtr = toCheck;
     XMLCh theChar;
     bool  inSpace = false;
-    while ( theChar = *startPtr )
+    while ( (theChar = *startPtr) != 0 )
     {
         if ( theChar == chSpace)
         {