5.8 Inserting an Array Field into a Compound Type: nc_insert_array_compound
Insert a named field into a compound type.
Usage
int nc_insert_array_compound(int ncid, nc_type xtype, char *name,
size_t offset, nc_type field_typeid,
int ndims, int *dim_sizes);
ncid- The ID of the file that contains the array type and the compound type.
xtype- The typeid for this compound type, as returned by nc_def_compound, or
nc_inq_var.
name- The name of the new field.
offset- Offset in byte from the beginning of the compound type for this
field.
field_typeid- The base type of the array to be inserted.
Errors
NC_NOERR- No error.
NC_EBADID- Bad group id.
NC_ENAMEINUSE- That name is in use. Field names must be unique within a compound type.
NC_EMAXNAME- Name exceed 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_ENOTINDEFINE- Not in define mode.
NC_ETYPEDEFINED- Attempt to change type that has already been committed. The first time
the file leaves define mode, all defined types are committed, and
can't be changed. If you wish to add an array to a compound type, you
must do so before the compound type is committed.
Example
This example comes from the test file libsrc4/tst_compounds.c, which
writes data about some Star Fleet officers who are known to use netCDF
data.
/* Since some aliens exists in different, or more than one,
* dimensions, StarFleet keeps track of the dimensional abilities
* of everyone on 7 dimensions. */
#define NUM_DIMENSIONS 7
struct dim_rec
{
int starfleet_id;
int abilities[NUM_DIMENSIONS];
};
struct dim_rec dim_data_out[DIM_LEN], dim_data_in[DIM_LEN];
/* Create some phoney data. */
for (i=0; i<DIM_LEN; i++)
{
/* snip */
/* Dimensional data. */
dim_data_out[i].starfleet_id = i;
for (j = 0; j < NUM_DIMENSIONS; j++)
dim_data_out[i].abilities[j] = j;
/* snip */
}
printf("*** testing compound variable containing an array of ints...");
{
nc_type field_typeid;
int dim_sizes[] = {NUM_DIMENSIONS};
/* Create a file with a compound type which contains an array of
* int. Write a little data. */
if (nc_create(FILE_NAME, NC_NETCDF4, &ncid)) ERR;
if (nc_def_compound(ncid, sizeof(struct dim_rec), "SFDimRec", &typeid)) ERR;
if (nc_insert_compound(ncid, typeid, "starfleet_id",
HOFFSET(struct dim_rec, starfleet_id), NC_INT)) ERR;
if (nc_insert_array_compound(ncid, typeid, "abilities",
HOFFSET(struct dim_rec, abilities), NC_INT, 1, dim_sizes)) ERR;
if (nc_inq_compound_field(ncid, xtype, 1, name, &offset, &field_typeid,
&field_ndims, field_sizes)) ERR;
if (strcmp(name, "abilities") || offset != 4 || field_typeid != NC_INT ||
field_ndims != 1 || field_sizes[0] != dim_sizes[0]) ERR;
if (nc_def_dim(ncid, STARDATE, DIM_LEN, &dimid)) ERR;
if (nc_def_var(ncid, "dimension_data", typeid, 1, dimids, &varid)) ERR;
if (nc_put_var(ncid, varid, dim_data_out)) ERR;
if (nc_close(ncid)) ERR;
/* Open the file and take a look. */
if (nc_open(FILE_NAME, NC_WRITE, &ncid)) ERR;
if (nc_inq_var(ncid, 0, name, &xtype, &ndims, dimids, &natts)) ERR;
if (strcmp(name, "dimension_data") || ndims != 1 || natts != 0 || dimids[0] != 0) ERR;
if (nc_inq_compound(ncid, xtype, name, &size, &nfields)) ERR;
if (nfields != 2 || size != sizeof(struct dim_rec) || strcmp(name, "SFDimRec")) ERR;
if (nc_inq_compound_field(ncid, xtype, 1, name, &offset, &field_typeid,
&field_ndims, field_sizes)) ERR;
if (strcmp(name, "abilities") || offset != 4 || field_typeid != NC_INT ||
field_ndims != 1 || field_sizes[0] != NUM_DIMENSIONS) ERR;
if (nc_get_var(ncid, varid, dim_data_in)) ERR;
for (i=0; i<DIM_LEN; i++)
{
if (dim_data_in[i].starfleet_id != dim_data_out[i].starfleet_id) ERR;
for (j = 0; j < NUM_DIMENSIONS; j++)
if (dim_data_in[i].abilities[j] != dim_data_out[i].abilities[j]) ERR;
}
if (nc_close(ncid)) ERR;
}
