diff --git a/dlib/array2d/array2d_kernel.h b/dlib/array2d/array2d_kernel.h
index 3e2b1468c..828eca3cf 100644
--- a/dlib/array2d/array2d_kernel.h
+++ b/dlib/array2d/array2d_kernel.h
@@ -160,6 +160,9 @@ namespace dlib
             set_size(rows,cols);
         }
 
+        array2d(const array2d&) = delete;        // copy constructor
+        array2d& operator=(const array2d&) = delete;    // assignment operator
+
 #ifdef DLIB_HAS_RVALUE_REFERENCES
         array2d(array2d&& item) : array2d()
         {
@@ -330,10 +333,6 @@ namespace dlib
         T* last;
         mutable bool at_start_;
 
-        // restricted functions
-        array2d(array2d&);        // copy constructor
-        array2d& operator=(array2d&);    // assignment operator
-
     };
 
 // ----------------------------------------------------------------------------------------
diff --git a/dlib/array2d/array2d_kernel_abstract.h b/dlib/array2d/array2d_kernel_abstract.h
index 82824dec6..cbb0e9b2b 100644
--- a/dlib/array2d/array2d_kernel_abstract.h
+++ b/dlib/array2d/array2d_kernel_abstract.h
@@ -122,6 +122,9 @@ namespace dlib
                 - std::bad_alloc 
         !*/
 
+        array2d(const array2d&) = delete;        // copy constructor
+        array2d& operator=(const array2d&) = delete;    // assignment operator
+
         array2d(
             array2d&& item
         );
@@ -252,12 +255,6 @@ namespace dlib
                   An example of such an object is the dlib::cv_image.
         !*/
 
-    private:
-
-        // restricted functions
-        array2d(array2d&);        // copy constructor
-        array2d& operator=(array2d&);    // assignment operator
-
     };
 
     template <
diff --git a/dlib/noncopyable.h b/dlib/noncopyable.h
index cbb603bcd..20b9866e7 100644
--- a/dlib/noncopyable.h
+++ b/dlib/noncopyable.h
@@ -19,8 +19,8 @@ namespace dlib
         !*/
 
     protected:
-        noncopyable() {}
-        ~noncopyable() {}
+        noncopyable() = default;
+        ~noncopyable() = default;
     private:  // emphasize the following members are private
         noncopyable(const noncopyable&);
         const noncopyable& operator=(const noncopyable&);