add a comment

diff --git a/include/deal.II/base/thread_local_storage.h b/include/deal.II/base/thread_local_storage.h
index 2c96321bb315c067538f0046fcdd9a0ed11c1522..59cdd3d9082b8d847fee45aed813d0cb755c4e79 100644 (file)
--- a/include/deal.II/base/thread_local_storage.h
+++ b/include/deal.II/base/thread_local_storage.h
@@ -230,6 +230,11 @@ namespace Threads
 
     /**
      * A mutex to guard insertion into the data object.
+     *
+     * We use a std::shared_timed_mutex (or std::shared_mutex if available)
+     * here to be able to use std::unique_lock and std::shared_lock for a
+     * readers-writer lock
+     * (https://en.wikipedia.org/wiki/Readers%E2%80%93writer_lock).
      */
 #  ifdef DEAL_II_HAVE_CXX17
     std::shared_mutex insertion_mutex;