From 5712a179d11eb2d0c4680e7913a55d1a4b958689 Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Thu, 27 Jan 2022 13:34:24 -0700
Subject: [PATCH] Improve the text of an assertion.

---
 include/deal.II/numerics/data_out_dof_data.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/deal.II/numerics/data_out_dof_data.h b/include/deal.II/numerics/data_out_dof_data.h
index e36f78a2b7..f9b81f6427 100644
--- a/include/deal.II/numerics/data_out_dof_data.h
+++ b/include/deal.II/numerics/data_out_dof_data.h
@@ -66,7 +66,9 @@ namespace Exceptions
     DeclExceptionMsg(ExcNoTriangulationSelected,
                      "For the operation you are attempting, you first need to "
                      "tell the DataOut or related object which DoFHandler or "
-                     "triangulation you would like to work on.");
+                     "triangulation you would like to work on. This is "
+                     "generally done using the 'attach_dof_handler()' or "
+                     "'attach_triangulation()' member functions.");
 
     /**
      * Exception
@@ -74,7 +76,9 @@ namespace Exceptions
     DeclExceptionMsg(ExcNoDoFHandlerSelected,
                      "For the operation you are attempting, you first need to "
                      "tell the DataOut or related object which DoFHandler "
-                     "you would like to work on.");
+                     "you would like to work on. This is "
+                     "generally done using the 'attach_dof_handler()' "
+                     "member function.");
 
     /**
      * Exception
-- 
2.39.5