1 files changed, 58 insertions, 0 deletions
diff --git a/Source/cmVariableWatchCommand.h b/Source/cmVariableWatchCommand.h
new file mode 100644
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+++ b/Source/cmVariableWatchCommand.h
@@ -0,0 +1,58 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+#ifndef cmVariableWatchCommand_h
+#define cmVariableWatchCommand_h
+
+#include <cmConfigure.h>
+#include <set>
+#include <string>
+#include <vector>
+
+#include "cmCommand.h"
+
+class cmExecutionStatus;
+
+/** \class cmVariableWatchCommand
+ * \brief Watch when the variable changes and invoke command
+ *
+ */
+class cmVariableWatchCommand : public cmCommand
+{
+public:
+  /**
+   * This is a virtual constructor for the command.
+   */
+  cmCommand* Clone() CM_OVERRIDE { return new cmVariableWatchCommand; }
+
+  //! Default constructor
+  cmVariableWatchCommand();
+
+  //! Destructor.
+  ~cmVariableWatchCommand() CM_OVERRIDE;
+
+  /**
+   * This is called when the command is first encountered in
+   * the CMakeLists.txt file.
+   */
+  bool InitialPass(std::vector<std::string> const& args,
+                   cmExecutionStatus& status) CM_OVERRIDE;
+
+  /**
+   * This determines if the command is invoked when in script mode.
+   */
+  bool IsScriptable() const CM_OVERRIDE { return true; }
+
+  /** This command does not really have a final pass but it needs to
+      stay alive since it owns variable watch callback information. */
+  bool HasFinalPass() const CM_OVERRIDE { return true; }
+
+  /**
+   * The name of the command as specified in CMakeList.txt.
+   */
+  std::string GetName() const CM_OVERRIDE { return "variable_watch"; }
+
+protected:
+  std::set<std::string> WatchedVariables;
+};
+
+#endif