From 71d9a45e2cb7993996994cce55b28476e184e7a9 Mon Sep 17 00:00:00 2001
From: wolf <wolf@0785d39b-7218-0410-832d-ea1e28bc413d>
Date: Mon, 26 Feb 2001 13:03:44 +0000
Subject: [PATCH] Work around a compiler bug in gcc2.95. (Takeover of fix from
 main branch.)

git-svn-id: https://svn.dealii.org/branches/Branch-3-1@4031 0785d39b-7218-0410-832d-ea1e28bc413d
---
 deal.II/deal.II/include/grid/tria.h          | 27 +++++++++++++++++---
 deal.II/deal.II/include/grid/tria_boundary.h |  6 ++++-
 deal.II/deal.II/source/grid/tria.cc          | 21 +++++++++++----
 3 files changed, 45 insertions(+), 9 deletions(-)

diff --git a/deal.II/deal.II/include/grid/tria.h b/deal.II/deal.II/include/grid/tria.h
index 8efd3bd745..1769b4a9b0 100644
--- a/deal.II/deal.II/include/grid/tria.h
+++ b/deal.II/deal.II/include/grid/tria.h
@@ -1589,8 +1589,29 @@ class Triangulation : public TriaDimensionInfo<dim>,
 				      * declaration is used for the
 				      * default argument in
 				      * @p{set_boundary}.
-				      */
-    static const StraightBoundary<dim> straight_boundary;
+				      *
+				      * The proper way would have been
+				      * to use a static object here,
+				      * rather than a pointer to an
+				      * object. However, we have to
+				      * work around a bug in gcc2.95,
+				      * where the compiler tries to
+				      * instantiate @p{Triangulation}
+				      * while instantiating
+				      * @p{Boundary} (which it needs
+				      * to do, since local typedefs
+				      * are involved), but then tries
+				      * to in turn instantiate
+				      * @p{StraightBoundary} because
+				      * of this member variable. This
+				      * is not needed since the member
+				      * variable is a static one, but
+				      * the compiler tries anyway and
+				      * finds that it can't since the
+				      * base class @p{Boundary} is not
+				      * yet complete...
+				      */
+    static const StraightBoundary<dim> *straight_boundary;
 
   public:
     
@@ -1737,7 +1758,7 @@ class Triangulation : public TriaDimensionInfo<dim>,
 				      * straight line.
 				      */
     void set_boundary (unsigned int         number,
-		       const Boundary<dim> &boundary_object = straight_boundary);
+		       const Boundary<dim> &boundary_object = *straight_boundary);
 
 				     /**
 				      * Return a constant reference to
diff --git a/deal.II/deal.II/include/grid/tria_boundary.h b/deal.II/deal.II/include/grid/tria_boundary.h
index 0e0f022091..4f294c2244 100644
--- a/deal.II/deal.II/include/grid/tria_boundary.h
+++ b/deal.II/deal.II/include/grid/tria_boundary.h
@@ -17,7 +17,11 @@
 /*----------------------------   boundary-function.h     ---------------------------*/
 
 #include <base/subscriptor.h>
-#include <grid/tria.h>
+#include <base/point.h>
+
+
+template <int dim> class Triangulation;
+
 
 
 /**
diff --git a/deal.II/deal.II/source/grid/tria.cc b/deal.II/deal.II/source/grid/tria.cc
index 9401a3884f..d6e4040b6a 100644
--- a/deal.II/deal.II/source/grid/tria.cc
+++ b/deal.II/deal.II/source/grid/tria.cc
@@ -28,8 +28,19 @@
 #include <cmath>
 
 
+
+// initialize the @p{straight_boundary} pointer of the triangulation
+// class. for the reasons why it is done like this, see the
+// documentation of that member variable
+namespace 
+{
+  const StraightBoundary<deal_II_dimension> dummy_straight_boundary;
+};
+
+
 template <int dim>
-const StraightBoundary<dim> Triangulation<dim>::straight_boundary;
+const StraightBoundary<dim> *
+Triangulation<dim>::straight_boundary = &dummy_straight_boundary;
 
 
 
@@ -41,8 +52,8 @@ Triangulation<dim>::Triangulation (const MeshSmoothing smooth_grid) :
 				   // set default boundary for all possible components
   for (unsigned int i=0;i<255;++i)
     {
-      boundary[i] = &straight_boundary;
-      straight_boundary.subscribe();
+      boundary[i] = straight_boundary;
+      boundary[i]->subscribe();
     }
 };
 
@@ -86,8 +97,8 @@ void Triangulation<dim>::clear ()
   for (unsigned int i=0; i<255; ++i)
     {
       boundary[i]->unsubscribe ();
-      boundary[i] = &straight_boundary;
-      straight_boundary.subscribe ();
+      boundary[i] = straight_boundary;
+      boundary[i]->subscribe ();
     };
 
   number_cache = TriaNumberCache<dim>();
-- 
2.39.5