Add BlockVectorBase iterator exception messages.

diff --git a/include/deal.II/lac/block_vector_base.h b/include/deal.II/lac/block_vector_base.h
index 219030cc2cfdea2056698c7e7a7da33bedbf82a1..575a087a23dc7d03ceecfaecd873e2c1417a47af 100644 (file)
--- a/include/deal.II/lac/block_vector_base.h
+++ b/include/deal.II/lac/block_vector_base.h
@@ -456,13 +456,20 @@ namespace internal
        */
 
       /**
-       * Exception.
+       * Exception thrown when one performs arithmetical comparisons on
+       * iterators belonging to two different block vectors.
        */
-      DeclException0 (ExcPointerToDifferentVectors);
+      DeclExceptionMsg (ExcPointerToDifferentVectors,
+                        "Your program tried to compare iterators pointing to "
+                        "different block vectors. There is no reasonable way "
+                        "to do this.");
+
       /**
-       * Exception.
+       * Exception thrown when one attempts to copy construct a non-const
+       * iterator from a const iterator.
        */
-      DeclException0 (ExcCastingAwayConstness);
+      DeclExceptionMsg (ExcCastingAwayConstness,
+                        "A copy of a const iterator should also be const.");
       //@}
     private:
       /**