Avoid out of bounds memory access

diff --git a/source/base/data_out_base.cc b/source/base/data_out_base.cc
index a6f1f8619711994260932dd23ce9246b8a5aaf7e..ebb4f197cb388d931151ec6f8f1377592ceb87dd 100644 (file)
--- a/source/base/data_out_base.cc
+++ b/source/base/data_out_base.cc
@@ -401,6 +401,10 @@ namespace DataOutBase
       const std::vector<Patch<dim, spacedim>> &patches,
       Table<2, Number> &                       data_vectors)
     {
+      // If there is nothing to write, just return
+      if (patches.size() == 0)
+        return;
+
       // unlike in the main function, we don't have here the data_names field,
       // so we initialize it with the number of data sets in the first patch.
       // the equivalence of these two definitions is checked in the main
@@ -7594,6 +7598,9 @@ DataOutBase::write_filtered_data(
   // no cells it actually owns, and in that case it is legit if there are no
   // patches
   Assert(patches.size() > 0, ExcNoPatches());
+#else
+  if (patches.size() == 0)
+         return;
 #endif
 
   compute_sizes<dim, spacedim>(patches, n_node, n_cell);