From: Wolfgang Bangerth <bangerth@math.tamu.edu>
Date: Tue, 7 Jun 2016 13:53:07 +0000 (-0500)
Subject: First call the signal, then destroy the object.
X-Git-Tag: v8.5.0-rc1~981^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f85ce5559db22e0eaa2942b4a2770241f8b07357;p=dealii.git

First call the signal, then destroy the object.
---

diff --git a/include/deal.II/grid/tria.h b/include/deal.II/grid/tria.h
index 7b9684280c..9608ad3986 100644
--- a/include/deal.II/grid/tria.h
+++ b/include/deal.II/grid/tria.h
@@ -2023,6 +2023,12 @@ public:
      * is called. This signal is also triggered when loading a triangulation
      * from an archive via Triangulation::load() as the previous content of
      * the triangulation is first destroyed.
+     *
+     * The signal is triggered before the data structures of the
+     * triangulation are destroyed. In other words, the functions
+     * attached to this signal get a last look at the triangulation,
+     * for example to save information stored as part of the
+     * triangulation.
      */
     boost::signals2::signal<void ()> clear;
 
diff --git a/source/grid/tria.cc b/source/grid/tria.cc
index 4b76e7b8d5..31b117337e 100644
--- a/source/grid/tria.cc
+++ b/source/grid/tria.cc
@@ -9024,13 +9024,13 @@ Triangulation<dim, spacedim>::~Triangulation ()
 template <int dim, int spacedim>
 void Triangulation<dim, spacedim>::clear ()
 {
-  // clear all content of the triangulation...
+  // notify listeners that the triangulation is going down...
+  signals.clear();
+
+  // ...and then actually clear all content of it
   clear_despite_subscriptions();
   periodic_face_pairs_level_0.clear();
   periodic_face_map.clear();
-
-  // ...and then notify listeners to it
-  signals.clear();
 }