MPI_File_iread_all - Nonblocking collective read using individual file pointer

fh     - file handle (handle)
       count  - number of elements in buffer (nonnegative integer)
       datatype
              - datatype of each buffer element (handle)

       MPI_File_iread_all -  Nonblocking collective read using individual file pointer

       All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have an additional argument ierr at the
       end of the argument list.  ierr is an integer and has the same meaning as the return value of the routine
       in C.  In Fortran, MPI routines are subroutines, and are invoked with the call statement.

       All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in Fortran.

                                                    1/21/2022                              MPI_File_iread_all(3)

buf    - initial address of buffer (choice)
       request
              - request object (handle)

       int MPI_File_iread_all(MPI_File fh, void *buf, int count,
       MPI_Datatype datatype, MPI_Request * request)