The MPI Objects

MPI_Request

Handle for nonblocking communication, normally freed by MPI in a test or wait

MPI_Datatype

MPI datatype. Free with MPI_Type_free.

MPI_Op

User-defined operation. Free with MPI_Op_free.

MPI_Comm

Communicator. Free with MPI_Comm_free.

MPI_Group

Group of processes. Free with MPI_Group_free.

MPI_Errhandler

MPI errorhandler. Free with MPI_Errhandler_free.