In addition to these basic formats, one can also create new MPI data types. These use a number of MPI functions, including MPI_Type_create_struct:

int MPI_Type_create_struct( 
   int count,  
   int array_of_blocklengths[], 
         const MPI_Aint array_of_displacements[],  
   const MPI_Datatype array_of_types[], 
         MPI_Datatype *newtype) 

With this function, one can create an MPI type that contains a struct, to be passed just like a basic MPI data type:

#include <cstdio> 
#include <cstdlib> 
#include <mpi.h> 
#include <cstddef> 
 
struct car { 
        int shifts; 
        int topSpeed; 
}; 
 
int main(int argc, char **argv) { 
         const int tag = 13; 
         int size, rank; 
 
         MPI_Init(&argc, &argv); 
         MPI_Comm_size(MPI_COMM_WORLD, &size); 
 
         if (size < 2) { 
               fprintf(stderr,"Requires at least two processes.\n"); 
               MPI_Abort(MPI_COMM_WORLD, 1); 
         } 
 
         const int nitems = 2; 
         int blocklengths[2] = {1,1}; 
   MPI_Datatype types[2] = {MPI_INT, MPI_INT}; 
         MPI_Datatype mpi_car_type; 
         MPI_Aint offsets[2]; 
 
         offsets[0] = offsetof(car, shifts); 
         offsets[1] = offsetof(car, topSpeed); 
 
         MPI_Type_create_struct(nitems, blocklengths, offsets, types, &mpi_car_type); 
         MPI_Type_commit(&mpi_car_type); 
 
         MPI_Comm_rank(MPI_COMM_WORLD, &rank); 
         if (rank == 0) { 
               car send; 
               send.shifts = 4; 
               send.topSpeed = 100; 
 
               const int dest = 1; 
                
         MPI_Send(&send, 1, mpi_car_type, dest, tag, MPI_COMM_WORLD); 
 
               printf("Rank %d: sent structure car\n", rank); 
         } 
          
   if (rank == 1) { 
               MPI_Status status; 
               const int src = 0; 
 
         car recv; 
 
         MPI_Recv(&recv, 1, mpi_car_type, src, tag, MPI_COMM_WORLD, &status); 
         printf("Rank %d: Received: shifts = %d topSpeed = %d\n", rank, recv.shifts, recv.topSpeed); 
    } 
 
    MPI_Type_free(&mpi_car_type); 
    MPI_Finalize(); 
 
         return 0; 
} 

Here we see how a new MPI data type called mpi_car_type is defined and used to message between two processes. To create a struct type like this, we need to define the number of items in the struct, the number of elements in each block, their byte displacement, and their basic MPI types.