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5.2.1.2 simple_xy_nc4_rd.c
     /* This is part of the netCDF package. Copyright 2007 University
        Corporation for Atmospheric Research/Unidata.  See COPYRIGHT file
        for conditions of use.
     
        This is a very simple example which is based on the simple_xy
        example, but whch uses netCDF-4 features, such as
        compression. Please see the simple_xy example to learn more about
        the netCDF-3 API.
     
        Like simple_xy_rd.c, this example reads a small dummy array, which
        was written by simple_xy_wr.c, and is compressed. This is intended
        to illustrate the use of the netCDF C API.
     
        This program is part of the netCDF-4 tutorial:
        http://www.unidata.ucar.edu/software/netcdf/netcdf-4/newdocs/netcdf-tutorial
     
        Full documentation of the netCDF-4 C API can be found at:
        http://www.unidata.ucar.edu/software/netcdf/netcdf-4/newdocs/netcdf-c
     
        $Id: simple_xy_nc4_rd.c,v 1.2 2007/06/05 21:47:50 ed Exp $
     */
     
     #include <config.h>
     #include <stdlib.h>
     #include <stdio.h>
     #include <netcdf.h>
     
     /* This is the name of the data file we will read. */
     #define FILE_NAME "simple_xy_nc4.nc"
     
     /* We are reading 2D data, a 6 x 12 grid. */
     #define NX 60
     #define NY 120
     
     /* Handle errors by printing an error message and exiting with a
      * non-zero status. */
     #define ERRCODE 2
     #define ERR(e) {printf("Error: %s\n", nc_strerror(e)); exit(ERRCODE);}
     
     int
     main()
     {
        /* This will be the netCDF ID for the file and data variable. */
        int ncid, varid;
     
        int data_in[NX][NY];
     
        /* Loop indexes, and error handling. */
        int x, y, retval;
     
        /* Open the file. NC_NOWRITE tells netCDF we want read-only access
         * to the file.*/
        if ((retval = nc_open(FILE_NAME, NC_NOWRITE, &ncid)))
           ERR(retval);
     
        /* Get the varid of the data variable, based on its name. */
        if ((retval = nc_inq_varid(ncid, "data", &varid)))
           ERR(retval);
     
        /* Read the data. */
        if ((retval = nc_get_var_int(ncid, varid, &data_in[0][0])))
           ERR(retval);
     
        /* Check the data. */
        for (x = 0; x < NX; x++)
           for (y = 0; y < NY; y++)
     	 if (data_in[x][y] != x * NY + y)
     	    return ERRCODE;
     
        /* Close the file, freeing all resources. */
        if ((retval = nc_close(ncid)))
           ERR(retval);
     
        printf("*** SUCCESS reading example file %s!\n", FILE_NAME);
        return 0;
     }