Leave a note in the documentation of class ArrayView.

diff --git a/include/deal.II/base/array_view.h b/include/deal.II/base/array_view.h
index 3ef61ed3f4c4d1f9b1665fd83303e294955489fc..cd71f8eace3158b89095faad624b3616286ea13d 100644 (file)
--- a/include/deal.II/base/array_view.h
+++ b/include/deal.II/base/array_view.h
@@ -66,6 +66,9 @@ DEAL_II_NAMESPACE_OPEN
  * therefore changes the std::vector object itself -- consequently, the
  * std::vector::operator[] is non-@p const.
  *
+ * @note This class is similar to std::span, but the latter is only
+ *  available in C++20.
+ *
  * @ingroup data
  * @author Wolfgang Bangerth, 2015, David Wells, 2017
  */