netcdf-c/examples/C/simple.c

/*! \file

  Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
  2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014,
  2015, 2016, 2017, 2018
  University Corporation for Atmospheric Research/Unidata.
  See \ref copyright file for more info.
*/

/* This example program is part of Unidata's netCDF library for
   scientific data access.

   How about a short, but meaningful, netCDF program?

   Ed Hartnett, 6/19/4
*/

#include <netcdf.h>
#include <stdio.h>
#include <string.h>

/* This macro handles errors by outputting a message to stdout and
   then exiting. */
#define NC_EXAMPLE_ERROR 2 /* This is the exit code for failure. */
#define BAIL(e) do {                                            \
        printf("Bailing out in file %s, line %d, error:%s.\n",  \
               __FILE__, __LINE__, nc_strerror(e));             \
        return NC_EXAMPLE_ERROR;                                \
    } while (0)

#define NUMDIMS 2
#define NUMVARS 1
#define CELSIUS "celsius"
#define LAT_LEN 3
#define LON_LEN 2

int
main()
{
    int ncid, temp_varid, dimids[NUMDIMS];
    float temp[LAT_LEN][LON_LEN], *fp;
    int i, res;

    /* Create a bunch of phoney data so we have something to write in
       the example file. */
    for (fp=(float *)temp, i=0; i<LAT_LEN*LON_LEN; i++)
        *fp++ = 10. + i/10.;

    /* Create the netCDF file. */
    if ((res = nc_create("short.nc", NC_CLOBBER, &ncid)))
        BAIL(res);

    /* Define dimensions. */
    if ((res = nc_def_dim(ncid, "latitude", LAT_LEN, dimids)))
        BAIL(res);
    if ((res = nc_def_dim(ncid, "longitude", LON_LEN, &dimids[1])))
        BAIL(res);

    /* Define the variable. */
    if ((res = nc_def_var(ncid, "sfc_temp", NC_FLOAT, NUMDIMS,
                          dimids, &temp_varid)))
        BAIL(res);

    /* We'll store the units. */
    if ((res = nc_put_att_text(ncid, temp_varid, "units",
                               strlen(CELSIUS), CELSIUS)))
        BAIL(res);

    /* We're finished defining metadata. */
    if ((res = nc_enddef(ncid)))
        BAIL(res);

    if ((res = nc_put_var_float(ncid, temp_varid, (float *)temp)))
        BAIL(res);

    /* We're done! */
    if ((res = nc_close(ncid)))
        BAIL(res);

    return 0;
}