IN: File dataspace selection identifier; H5S_ALL if the selection is the current extent of the dataset (See NOTE below)
hsize_t * nchunks
IN/OUT: Number of chunks in the selection
H5D_GET_NUM_CHUNKS retrieves the number of chunks nchunks in a set of selected elements specified by fspace_id for a dataset specified by the identifier dset_id. If fspace_id is H5S_ALL, the function will retrieve the total number of chunks stored for the dataset.
NOTE: Please be aware that in the HDF5-1.10.5 release, the dataspace intersection was not yet completed. With this version the number of written chunks will be returned.
Returns a non-negative value if successful. Otherwise returns a negative value.