diff --git a/simplecpp.cpp b/simplecpp.cpp
index c2e1bca..1c006b0 100755
--- a/simplecpp.cpp
+++ b/simplecpp.cpp
@@ -1481,8 +1481,7 @@ namespace simplecpp {
 
         Macro(const std::string &name, const std::string &value, std::vector<std::string> &f) : nameTokDef(nullptr), files(f), tokenListDefine(f), valueDefinedInCode_(false) {
             const std::string def(name + ' ' + value);
-            std::istringstream istr(def);
-            StdIStream stream(istr);
+            StdStringStream stream(def);
             tokenListDefine.readfile(stream);
             if (!parseDefine(tokenListDefine.cfront()))
                 throw std::runtime_error("bad macro syntax. macroname=" + name + " value=" + value);