diff --git a/Source/cmEnableTestingCommand.h b/Source/cmEnableTestingCommand.h
index 3bc5534c50..d03b218966 100644
--- a/Source/cmEnableTestingCommand.h
+++ b/Source/cmEnableTestingCommand.h
@@ -53,7 +53,7 @@ public:
    * This is called when the command is first encountered in
    * the CMakeLists.txt file.
    */
-  virtual bool InitialPass(std::vector<std::string> const&) {return true;}
+  virtual bool InitialPass(std::vector<std::string> const&);
 
   /**
    * This is called at the end after all the information