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diff --git a/Source/cmFileTimeComparison.h b/Source/cmFileTimeComparison.h
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+++ b/Source/cmFileTimeComparison.h
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+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+#ifndef cmFileTimeComparison_h
+#define cmFileTimeComparison_h
+
+#include "cmConfigure.h" // IWYU pragma: keep
+
+#include <string>
+
+class cmFileTimeComparisonInternal;
+
+/** \class cmFileTimeComparison
+ * \brief Helper class for comparing file modification times.
+ *
+ * Compare file modification times or test if file modification times differ.
+ */
+class cmFileTimeComparison
+{
+public:
+  cmFileTimeComparison();
+  ~cmFileTimeComparison();
+
+  cmFileTimeComparison(const cmFileTimeComparison&) = delete;
+  cmFileTimeComparison& operator=(const cmFileTimeComparison&) = delete;
+
+  /**
+   *  Compare file modification times.
+   *  Return true for successful comparison and false for error.
+   *  When true is returned, result has -1, 0, +1 for
+   *  f1 older, same, or newer than f2.
+   */
+  bool FileTimeCompare(const std::string& f1, const std::string& f2,
+                       int* result);
+
+  /**
+   *  Compare file modification times.  Return true unless both files
+   *  exist and have modification times less than 1 second apart.
+   */
+  bool FileTimesDiffer(const std::string& f1, const std::string& f2);
+
+protected:
+  cmFileTimeComparisonInternal* Internals;
+};
+
+#endif