3.3 Get a Dimension ID from Its Name: ncmpi_inq_dimid

The function ncmpi_inq_dimid returns (as an argument) the ID of a netCDF dimension, given the name of the dimension. If ndims is the number of dimensions defined for a netCDF file, each dimension has an ID between 0 and ndims-1.

Operational Mode

This API is an independent subroutine and can be called while the file is in either define or data mode (collective or independent).

Usage

int ncmpi_inq_dimid(int         ncid,
                    const char *name,
                    int        *dimidp);

ncid

NetCDF ID, an input argument obtained from a previous call to ncmpi_open or ncmpi_create.

name

Dimension name, an input argument, a character string beginning with a letter and followed by any sequence of letters, digits, or underscore (’_’) characters. Case is significant in dimension names.

dimidp

Pointer to location for the returned dimension ID (output).

Return Error Codes

ncmpi_inq_dimid returns the value NC_NOERR if no errors occurred. Otherwise, the returned status indicates an error. Possible causes of errors include:

• NC_EBADID: The specified netCDF ID does not refer to an opened netCDF file.
• NC_EBADDIM: The name that was specified is not the name of a dimension in the netCDF file.

Example

Here is an example using ncmpi_inq_dimid to determine the dimension ID of a dimension named lat, assumed to have been defined previously in an existing netCDF file named foo.nc:

#include <pnetcdf.h>
   ...
int status, ncid, latid;
   ...
status = ncmpi_open(MPI_COMM_WORLD, "foo.nc", NC_NOWRITE, MPI_INFO_NULL, &ncid);  /* open for reading */
if (status != NC_NOERR) handle_error(status);
   ...
status = ncmpi_inq_dimid(ncid, "lat", &latid);
if (status != NC_NOERR) handle_error(status);