Avoid a warning in optimized mode.

diff --git a/source/lac/slepc_spectral_transformation.cc b/source/lac/slepc_spectral_transformation.cc
index e4d8503a3b7c3e8e12017b35726d10f18401a925..da0087a096616ba0cf2b2cbd681ce89d0d77fbff 100644 (file)
--- a/source/lac/slepc_spectral_transformation.cc
+++ b/source/lac/slepc_spectral_transformation.cc
@@ -42,6 +42,7 @@ namespace SLEPcWrappers
     if (st!=nullptr)
       {
         const PetscErrorCode ierr = STDestroy(&st);
+        (void)ierr;
         AssertNothrow (ierr == 0, SolverBase::ExcSLEPcError(ierr));
       }
   }