Add necessary include files to a code snippet in the glossary.

diff --git a/doc/doxygen/headers/glossary.h b/doc/doxygen/headers/glossary.h
index 066cb3907bf2501e579d1fe23f5c66b0bba31d26..49bd65f11410d496efaab1c44218a7b91caab216 100644 (file)
--- a/doc/doxygen/headers/glossary.h
+++ b/doc/doxygen/headers/glossary.h
@@ -354,6 +354,11 @@
  * has read in from the mesh file. This can be done by using the
  * DataPostprocessors::BoundaryIds class and the following small piece of code:
  * @code
+ *    #include <deal.II/numerics/data_out_faces.h>
+ *    #include <deal.II/numerics/data_postprocessor.h>
+ *
+ *    ...
+ *
  *    DataPostprocessors::BoundaryIds<dim> boundary_ids;
  *    DataOutFaces<dim> data_out_faces;
  *    FE_Q<dim>         dummy_fe(1);