+Datatype_contents::Datatype_contents(int combiner, int number_of_integers, const int* integers, int number_of_addresses,
+ const MPI_Aint* addresses, int number_of_datatypes, const MPI_Datatype* datatypes)
+ : combiner_(combiner)
+ , integers_(integers, integers + number_of_integers)
+ , addresses_(addresses, addresses + number_of_addresses)
+ , datatypes_(datatypes, datatypes + number_of_datatypes)
+{
+ for (auto& datatype : datatypes_)
+ datatype->ref();
+}