5.28 Creating a Enum Type: nc_def_enum
Create an enum type. Provide an ncid, a name, and a base integer
type.
After calling this function, fill out the type with repeated calls to
nc_insert_enum (see nc_insert_enum). Call nc_insert_enum once for
each value you wish to make part of the enumeration.
Usage
int nc_def_enum(int ncid, nc_type base_typeid, const char *name,
nc_type *typeidp);
ncid- The groupid where this compound type will be created.
base_typeid- The base integer type for this enum. Must be one of: NC_BYTE,
NC_UBYTE, NC_SHORT, NC_USHORT, NC_INT, NC_UINT, NC_INT64, NC_UINT64.
name- The name of the new enum type.
typeidp- A pointer to an nc_type. The typeid of the new type will be placed
there.
Errors
NC_NOERR- No error.
NC_EBADID- Bad group id.
NC_ENAMEINUSE- That name is in use.
NC_EMAXNAME- Name exceeds max length NC_MAX_NAME.
NC_EBADNAME- Name contains illegal characters.
NC_ENOTNC4- Attempting a netCDF-4 operation on a netCDF-3 file. NetCDF-4
operations can only be performed on files defined with a create mode
which includes flag NC_NETCDF4. (see nc_open).
NC_ESTRICTNC3- This file was created with the strict netcdf-3 flag, therefore
netcdf-4 operations are not allowed. (see nc_open).
NC_EHDFERR- An error was reported by the HDF5 layer.
NC_EPERM- Attempt to write to a read-only file.
NC_ENOTINDEFINE- Not in define mode.
The following example, from libsrc4/tst_enums.c, shows the creation
and use of an enum type, including the use of a fill value.
int dimid, varid;
size_t num_members_in;
int class_in;
unsigned char value_in;
enum clouds { /* a C enumeration */
CLEAR=0,
CUMULONIMBUS=1,
STRATUS=2,
STRATOCUMULUS=3,
CUMULUS=4,
ALTOSTRATUS=5,
NIMBOSTRATUS=6,
ALTOCUMULUS=7,
CIRROSTRATUS=8,
CIRROCUMULUS=9,
CIRRUS=10,
MISSING=255};
struct {
char *name;
unsigned char value;
} cloud_types[] = {
{"Clear", CLEAR},
{"Cumulonimbus", CUMULONIMBUS},
{"Stratus", STRATUS},
{"Stratocumulus", STRATOCUMULUS},
{"Cumulus", CUMULUS},
{"Altostratus", ALTOSTRATUS},
{"Nimbostratus", NIMBOSTRATUS},
{"Altocumulus", ALTOCUMULUS},
{"Cirrostratus", CIRROSTRATUS},
{"Cirrocumulus", CIRROCUMULUS},
{"Cirrus", CIRRUS},
{"Missing", MISSING}
};
int var_dims[VAR2_RANK];
unsigned char att_val;
unsigned char cloud_data[DIM2_LEN] = {
CLEAR, STRATUS, CLEAR, CUMULONIMBUS, MISSING};
unsigned char cloud_data_in[DIM2_LEN];
if (nc_create(FILE_NAME, NC_CLOBBER | NC_NETCDF4, &ncid)) ERR;
/* Create an enum type. */
if (nc_def_enum(ncid, NC_UBYTE, TYPE2_NAME, &typeid)) ERR;
num_members = (sizeof cloud_types) / (sizeof cloud_types[0]);
for (i = 0; i < num_members; i++)
if (nc_insert_enum(ncid, typeid, cloud_types[i].name,
&cloud_types[i].value)) ERR;
/* Declare a station dimension */
if (nc_def_dim(ncid, DIM2_NAME, DIM2_LEN, &dimid)) ERR;
/* Declare a variable of the enum type */
var_dims[0] = dimid;
if (nc_def_var(ncid, VAR2_NAME, typeid, VAR2_RANK, var_dims, &varid)) ERR;
/* Create and write a variable attribute of the enum type */
att_val = MISSING;
if (nc_put_att(ncid, varid, ATT2_NAME, typeid, ATT2_LEN, &att_val)) ERR;
if (nc_enddef(ncid)) ERR;
/* Store some data of the enum type */
if(nc_put_var(ncid, varid, cloud_data)) ERR;
/* Write the file. */
if (nc_close(ncid)) ERR;
