; create HDF5 file  
file = 'hdf5_out.h5'  
fid = H5F_CREATE(file)  
  
; create some data  
data = hanning(100,200)  
  
; create a datatype  
datatype_id = H5T_IDL_CREATE(data)  
  
; create a dataspace, allow the dataspace to be extendable  
dataspace_id = $  
   H5S_CREATE_SIMPLE([100,100],max_dimensions=[200,200])  
  
; create the dataset  
dataset_id = H5D_CREATE(fid,'Hanning',datatype_id,dataspace_id, $  
   chunk_dimensions=[20,20])  
  
; extend the size of the dataset to fit the data  
H5D_EXTEND,dataset_id,size(data,/dimensions)  
  
; write the data to the dataset  
H5D_WRITE,dataset_id,data  
  
; close some identifiers  
H5S_CLOSE,dataspace_id  
H5T_CLOSE,datatype_id  
  
; create a reference attribute attached to the dataset  
dataspace_id = H5S_CREATE_SIMPLE(size(data,/dimensions))  
  
; select a 30x30 element region of interest in the dataset  
H5S_SELECT_HYPERSLAB,dataspace_id,[40,40],[1,1], $  
   block=[30,30],/reset  
  
; create a dataspace region reference  
ref = H5R_CREATE(fid,'Hanning',dataspace=dataspace_id)  
  
; create a datatype for the reference  
datatype_id = H5T_REFERENCE_CREATE(/region)  
  
; create a one element dataspace for the single reference  
dataspace_id = H5S_CREATE_SIMPLE(1)  
  
; make the reference an attribute of the dataset   
attr_id = H5A_CREATE(dataset_id,'Ref',datatype_id,dataspace_id)  
H5A_WRITE,attr_id,ref  
H5A_CLOSE,attr_id  
  
; create a dummy attribute and delete it  
attr_id2 = $  
H5A_CREATE(dataset_id,'Dummy',datatype_id,dataspace_id)  
  
; attribute must be closed before it can be deleted  
H5A_CLOSE,attr_id2  
H5A_DELETE,dataset_id,'Dummy'  
  
; create a group to hold sample datatypes and links  
group_id = H5G_CREATE(fid,'Datatypes and links')  
  
; add a comment to the group  
H5G_SET_COMMENT,fid,'Datatypes and links', $  
   'This is a sample comment'  
; add a datatype to the group  
datatype_id2 = H5T_IDL_CREATE(1)  
  
; add the datatype to the group and give it a name  
H5T_COMMIT,group_id,'Integer',datatype_id2  
  
; create an array datatype and add it to the group with a name  
datatype_id3 = H5T_ARRAY_CREATE(datatype_id2,[3,4])  
H5T_COMMIT,group_id,'Integer 2',datatype_id3  
  
; rename previous datatype  
H5G_MOVE,group_id,'Integer 2','Integer Array'  
  
; close temporary datatypes  
H5T_CLOSE,datatype_id3  
H5T_CLOSE,datatype_id2  
  
; create a compound datatype and add it to the group  
struct = {float:1.0, double:1.0d}  
datatype_id4 = $  
   H5T_IDL_CREATE(struct,member_names=['Float','Double'])  
  
; create an integer datatype and insert it in the   
; compound datatype  
datatype_id5 = H5T_IDL_CREATE(1)  
H5T_INSERT,datatype_id4,'Integer',datatype_id5  
  
; add the datatype to the group and give it a name  
H5T_COMMIT,group_id,'Compound',datatype_id4  
  
; close datatype identifiers  
H5T_CLOSE,datatype_id5  
H5T_CLOSE,datatype_id4  
  
; add a hard link from the group to the Hanning dataset   
H5G_LINK,fid,'Hanning','Link to Hanning',new_loc_id=group_id  
  
; add a dummy link  
H5G_LINK,group_id,'Integer','Link to Integer'  
  
; remove dummy link  
H5G_UNLINK,group_id,'Link to Integer'  
  
; close remaining open identifiers  
H5G_CLOSE,group_id  
H5D_CLOSE,dataset_id  
H5T_CLOSE,datatype_id  
H5S_CLOSE,dataspace_id  
H5F_CLOSE,fid  

Version History

See Also

H5F_CLOSE

  IDL Online Help (March 06, 2007)