Fix missing const.

git-svn-id: https://svn.dealii.org/branches/Branch-3-1@4167 0785d39b-7218-0410-832d-ea1e28bc413d

diff --git a/deal.II/lac/include/lac/precondition_selector.h b/deal.II/lac/include/lac/precondition_selector.h
index cc1677b76169b84b595adf463011cb92bad97881..8eb93c492e55b8cf82f5d61f98148458d0d40a13 100644 (file)
--- a/deal.II/lac/include/lac/precondition_selector.h
+++ b/deal.II/lac/include/lac/precondition_selector.h
@@ -153,7 +153,7 @@ class PreconditionSelector : public Subscriptor
 
 template <class Matrix, class Vector>
 PreconditionSelector<Matrix,Vector>
-::PreconditionSelector(std::string                       &preconditioning,
+::PreconditionSelector(const std::string                 &preconditioning,
                       const typename Vector::value_type &omega) :
                preconditioning(preconditioning),
                omega(omega)  {}