interop.c

The example for Boor USING MPI2

#include "mpi.h"
int main( int argc, char *argv[] )
{
    MPI_Aint lb, extent, extent_in_file;
    MPI_Datatype etype, filetype, contig;
    MPI_Offset disp;
    MPI_File fh;
    int buf[1000];

    MPI_Init( &argc, &argv );
    
    /* ... */

    MPI_File_open(MPI_COMM_WORLD, "/pfs/datafile", 
		  MPI_MODE_CREATE | MPI_MODE_RDWR, 
		  MPI_INFO_NULL, &fh);

    MPI_File_set_view(fh, 0, MPI_BYTE, MPI_BYTE, "external32", 
		      MPI_INFO_NULL);
    MPI_File_get_type_extent(fh, MPI_INT, &extent_in_file);

    MPI_Type_contiguous(2, MPI_INT, &contig);
    lb = 0;
    extent = 6 * extent_in_file;
    MPI_Type_create_resized(contig, lb, extent, &filetype);
    MPI_Type_commit(&filetype);

    disp = 5 * extent_in_file;
    etype = MPI_INT;

    MPI_File_set_view(fh, disp, etype, filetype, "external32", 
		      MPI_INFO_NULL);
    MPI_File_write(fh, buf, 1000, MPI_INT, MPI_STATUS_IGNORE);
 
    /* ... */
    MPI_Finalize();
    return 0;
}