diff --git a/CommandLineArguments.cxx b/CommandLineArguments.cxx
index a97f7a8365d9464286ec4ac35fed94378e4edc3a..dc9f01d97b158b792ab02ae9cc64843a19e834cf 100644
--- a/CommandLineArguments.cxx
+++ b/CommandLineArguments.cxx
@@ -67,10 +67,10 @@ class CommandLineArgumentsInternal
 {
 public:
   CommandLineArgumentsInternal()
+    : UnknownArgumentCallback{ KWSYS_NULLPTR }
+    , ClientData{ KWSYS_NULLPTR }
+    , LastArgument{ 0 }
   {
-    this->UnknownArgumentCallback = KWSYS_NULLPTR;
-    this->ClientData = KWSYS_NULLPTR;
-    this->LastArgument = 0;
   }
 
   typedef CommandLineArgumentsVectorOfStrings VectorOfStrings;