%**************************************************************************
%
%  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);