%**************************************************************************
%
% This example shows how to read and write variable-length
% string datatypes to an attribute. The program first
% writes variable-length strings to an attribute with a
% dataspace of DIM0, then closes the file. Next, it reopens
% the file, reads back the data, and outputs it to the
% screen.
%
% This file is intended for use with HDF5 Library verion 1.6
%
%**************************************************************************
fileName = 'h5ex_t_vlstringatt.h5';
DATASET = 'DS1';
ATTRIBUTE = 'A1';
DIM0 = 4;
dims = DIM0;
wdata = ['Parting'; 'is such'; 'sweet '; 'sorrow.'];
%
%% Create a new file using the default properties.
%
file = H5F.create (fileName, 'H5F_ACC_TRUNC', 'H5P_DEFAULT', 'H5P_DEFAULT');
%
% Create file and memory datatypes. For this example we will save
% the strings as FORTRAN strings.
%
filetype = H5T.copy ('H5T_FORTRAN_S1');
H5T.set_size (filetype,7);
memtype = H5T.copy ('H5T_C_S1');
H5T.set_size (memtype, 7);
%
% Create dataset with a scalar dataspace.
%
space = H5S.create ('H5S_SCALAR');
dset = H5D.create (file, DATASET, 'H5T_STD_I32LE', space, 'H5P_DEFAULT');
H5S.close (space);
%
% Create dataspace. Setting maximum size to [] sets the maximum
% size to be the current size.
%
space = H5S.create_simple (1,fliplr( dims), []);
%
% Create the attribute and write the variable-length string data
% to it.
%
attr = H5A.create (dset, ATTRIBUTE, filetype, space, 'H5P_DEFAULT');
H5A.write (attr, memtype, wdata');
%
% Close and release resources.
%
H5A.close (attr);
H5D.close (dset);
H5S.close (space);
H5T.close (filetype);
H5T.close (memtype);
H5F.close (file);
%
%% Now we begin the read section of this example. Here we assume
% the attribute has the same name and rank, but can have any size.
%
%
% Open file, dataset, and attribute.
%
file = H5F.open (fileName, 'H5F_ACC_RDONLY', 'H5P_DEFAULT');
dset = H5D.open (file, DATASET);
attr = H5A.open_name (dset, ATTRIBUTE);
%
% Get the datatype.
%
filetype = H5A.get_type (attr);
%
% Get dataspace and allocate memory for read buffer.
%
space = H5A.get_space (attr);
[numdims dims maxdims] = H5S.get_simple_extent_dims (space);
dims=fliplr(dims');
%
% Create the memory datatype.
%
memtype = H5T.copy ('H5T_C_S1');
%H5T.set_size (memtype, H5ML.get_constant_value('H5T_VARIABLE'));
H5T.set_size (memtype, 8);
%
% Read the data.
%
rdata = H5A.read (attr, memtype);
%
% Output the data to the screen.
%
for i=1: dims(1)
fprintf ('%s[%d]: %s\n', ATTRIBUTE, i, char(rdata(:,i)));
end
%
% Close and release resources.
%
H5A.close (attr);
H5D.close (dset);
H5S.close (space);
H5T.close (filetype);
H5T.close (memtype);
H5F.close (file);