diff --git a/Source/cmake.cxx b/Source/cmake.cxx
index d3801ccc1..7e7d2f724 100644
--- a/Source/cmake.cxx
+++ b/Source/cmake.cxx
@@ -1017,7 +1017,7 @@ int cmake::ExecuteCMakeCommand(std::vector<std::string>& args)
         }
       cmsys::Directory dir;
       dir.Load(dirName.c_str());
-      size_t fileNum = dir.GetNumberOfFiles();
+      int fileNum = static_cast<int>(dir.GetNumberOfFiles());
       // read the count
       fName = dirName;
       fName += "/count.txt";