diff --git a/Source/cmAddDefinitionsCommand.cxx b/Source/cmAddDefinitionsCommand.cxx
index 75f84eaf82..14f65b36b8 100644
--- a/Source/cmAddDefinitionsCommand.cxx
+++ b/Source/cmAddDefinitionsCommand.cxx
@@ -19,10 +19,10 @@
 // cmAddDefinitionsCommand
 bool cmAddDefinitionsCommand::InitialPass(std::vector<std::string> const& argsIn)
 {
+  // it is OK to have no arguments
   if(argsIn.size() < 1 )
     {
-    this->SetError("called with incorrect number of arguments");
-    return false;
+    return true;
     }
   std::vector<std::string> args;
   cmSystemTools::ExpandListArguments(argsIn, args);