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Get Number of Bytes for a Data Type

The function nctypelen (or NCTLEN for FORTRAN) returns the number of bytes per netCDF data type.

In case of an error, nctypelen returns -1; NCTLEN returns a nonzero value in rcode. One possible cause of errors is:

• The specified data type is not a valid netCDF data type.

nctypelen: C Interface

int nctypelen (nc_type datatype);

datatype

One of the set of predefined netCDF data types. The type of this parameter, nc_type, is defined in the netCDF header file. The valid netCDF data types are NC_BYTE, NC_CHAR, NC_SHORT, NC_LONG, NC_FLOAT, and NC_DOUBLE.

#include "netcdf.h"
   ...
int  ncid;        /* netCDF ID */
int  rh_id;       /* variable ID */
nc_type rh_type;           /* variable type */
int rh_ndims;              /* number of dims */
int rh_dims[MAX_VAR_DIMS]; /* variable shape */
int rh_natts;              /* number of attributes */
int rhbytes;      /* number of bytes per value for "rh" */
   ...
ncid = ncopen("foo.nc", NC_NOWRITE);
   ...
rh_id = ncvarid (ncid, "rh");
/* get type.  we don't need name, since we already know it */
ncvarinq (ncid, rh_id, (char *) 0, &rh_type, &rh_ndims, rh_dims,
          &rh_natts);
rhbytes = nctypelen (rh_type);

NCTLEN: FORTRAN Interface

      INTEGER FUNCTION NCTLEN (INTEGER TYPE ,INTEGER RCODE)

TYPE

One of the set of predefined netCDF data types. The valid netCDF data types are NCBYTE, NCCHAR, NCSHORT, NCLONG, NCFLOAT, and NCDOUBLE.

RCODE

Returned error code. If no errors occurred, 0 is returned.

Here is an example using NCTLEN to determine how many bytes are required to store a single value of the variable rh in an existing netCDF file named `foo.nc':

      INCLUDE 'netcdf.inc'
         ...
      INTEGER  NCID              ! netCDF ID
      INTEGER  RHID               ! variable ID
      CHARACTER*31 RHNAME         ! variable name
      INTEGER  RHTYPE             ! variable type
      INTEGER  RHN                ! number of dimensions
      INTEGER  RHDIMS(MAXVDIMS)   ! variable shape
      INTEGER  RHNATT             ! number of attributes
      INTEGER  RHBYTS             ! bytes per value
         ...
      NCID = NCOPN ('foo.nc', NCNOWRIT, RCODE)
         ...
      RHID = NCVID (NCID, 'rh', RCODE)
* get type of "rh"
      CALL NCVINQ (NCID, RHID, RHNAME, RHTYPE, RHN, RHDIMS, RHNATT,
     +             RCODE)
      RHBYTS = NCTLEN (RHTYPE)

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