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2.1.1.2 simple_xy_rd.c
     /* This is part of the netCDF package.
        Copyright 2006 University Corporation for Atmospheric Research/Unidata.
        See COPYRIGHT file for conditions of use.
     
        This is a simple example which reads a small dummy array, which was
        written by simple_xy_wr.c. This is intended to illustrate the use
        of the netCDF C API.
     
        This program is part of the netCDF tutorial:
        http://www.unidata.ucar.edu/software/netcdf/docs/netcdf-tutorial
     
        Full documentation of the netCDF C API can be found at:
        http://www.unidata.ucar.edu/software/netcdf/docs/netcdf-c
     
        $Id: simple_xy_rd.c,v 1.9 2006/08/17 23:00:55 russ Exp $
     */
     #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.nc"
     
     /* We are reading 2D data, a 6 x 12 grid. */
     #define NX 6
     #define NY 12
     
     /* 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;
     }