The following are defined C type definitions, included in the file mpi.h.
/* C opaque types */ MPI_Aint MPI_Fint MPI_Offset MPI_Status /* C handles to assorted structures */ MPI_Comm MPI_Datatype MPI_Errhandler MPI_File MPI_Group MPI_Info MPI_Op MPI_Request MPI_Win // C++ opaque types (all within the MPI namespace) MPI::Aint MPI::Offset MPI::Status // C++ handles to assorted structures (classes, // all within the MPI namespace) MPI::Comm MPI::Intracomm MPI::Graphcomm MPI::Cartcomm MPI::Intercomm MPI::Datatype MPI::Errhandler MPI::Exception MPI::File MPI::Group MPI::Info MPI::Op MPI::Request MPI::Prequest MPI::Grequest MPI::Win