4.4 Inquire about a Dimension: nc_inq_dim Family
This family of functions returns information about a netCDF
dimension. Information about a dimension includes its name and its
length. The length for the unlimited dimension, if any, is the number
of records written so far.
The functions in this family include nc_inq_dim, nc_inq_dimname, and
nc_inq_dimlen. The function nc_inq_dim returns all the information
about a dimension; the other functions each return just one item of
information.
Usage
int nc_inq_dim (int ncid, int dimid, char* name, size_t* lengthp);
int nc_inq_dimname (int ncid, int dimid, char *name);
int nc_inq_dimlen (int ncid, int dimid, size_t *lengthp);
ncid- NetCDF ID, from a previous call to nc_open or nc_create.
dimid- Dimension ID, from a previous call to nc_inq_dimid or nc_def_dim.
name- Returned dimension name. The caller must allocate space for the
returned name. The maximum possible length, in characters, of a
dimension name is given by the predefined constant NC_MAX_NAME. (This
doesn't include the null terminator, so declare your array to be size
NC_MAX_NAME+1). The returned character array will be null-terminated.
lengthp- Pointer to location for returned length of dimension. For the
unlimited dimension, this is the number of records written so far.
Errors
These functions return the value NC_NOERR if no errors
occurred. Otherwise, the returned status indicates an error. Possible
causes of errors include:
- The dimension ID is invalid for the specified netCDF dataset.
- The specified netCDF ID does not refer to an open netCDF dataset.
Example
Here is an example using nc_inq_dim to determine the length of a
dimension named lat, and the name and current maximum length of the
unlimited dimension for an existing netCDF dataset named foo.nc:
#include <netcdf.h>
...
int status, ncid, latid, recid;
size_t latlength, recs;
char recname[NC_MAX_NAME+1];
...
status = nc_open("foo.nc", NC_NOWRITE, &ncid); /* open for reading */
if (status != NC_NOERR) handle_error(status);
status = nc_inq_unlimdim(ncid, &recid); /* get ID of unlimited dimension */
if (status != NC_NOERR) handle_error(status);
...
status = nc_inq_dimid(ncid, "lat", &latid); /* get ID for lat dimension */
if (status != NC_NOERR) handle_error(status);
status = nc_inq_dimlen(ncid, latid, &latlength); /* get lat length */
if (status != NC_NOERR) handle_error(status);
/* get unlimited dimension name and current length */
status = nc_inq_dim(ncid, recid, recname, &recs);
if (status != NC_NOERR) handle_error(status);
