Routines (alphabetical) > Routines: H > HDF5 Routines > H5D_EXTEND

# H5D_EXTEND

The Dataspace of a dataset defines the number of dimensions and the size of each dimension. H5D_EXTEND is used to change the current dimensions of the Dataset, within the limits of the Dataspace. Each dimension can be extended up to its maximum, or unlimited. The maximum dimension size is set when the Dataset is created and cannot be changed. The size of the dataset cannot be reduced after it is created. The actual dimension size can be incremented with calls to H5D_EXTEND, up to the maximum.

## Example

See the example under H5F_CREATE.

## Syntax

H5D_EXTEND,Dataset_id, Size

## Arguments

### Dataset_id

An integer giving the dataset identifier to extend.

### Size

Array containing the new magnitude of each dimension. The number of elements in Size must match the number of dimensions of the dataset.

Note: The Size argument should be specified in IDL column-major order. Internally, the dimensions will be reversed to match HDF5/C row-major order.

## Keywords

None

## Version History

6.2 | Introduced

## See Also

H5D_CREATE