%**************************************************************************
%
%  This example shows how to commit a named datatype to a
%  file, and read back that datatype.  The program first
%  defines a compound datatype, commits it to a file, then
%  closes the file.  Next, it reopens the file, opens the
%  datatype, and outputs the names of its fields to the
%  screen.
%
%  This file is intended for use with HDF5 Library verion 1.6
%
%**************************************************************************

fileName       = 'h5ex_t_commit.h5';
DATATYPE       = 'Sensor_Type';

%
%% Create a new file using the default properties.
%
file = H5F.create (fileName, 'H5F_ACC_TRUNC', 'H5P_DEFAULT', 'H5P_DEFAULT');

%
% Create the compound datatype.  Because the standard types we are
% using may have different sizes than the corresponding native
% types, we must manually calculate the offset of each member.
%
filetype = H5T.create ('H5T_COMPOUND', 8 + 8 + 8);
H5T.insert (filetype, 'serial_number', 0, 'H5T_STD_I64BE');
H5T.insert (filetype, 'temperature_F', 8 ,'H5T_IEEE_F64BE');
H5T.insert (filetype, 'pressure_inHg', 8 + 8,'H5T_IEEE_F64BE');

%
% Commit the compound datatype to the file, creating a named
% datatype.
%
H5T.commit (file, DATATYPE, filetype);

%
% Close and release resources.
%
H5T.close (filetype);
H5F.close (file);


%
%% Now we begin the read section of this example.
%

%
% Open file.
%
file = H5F.open (fileName, 'H5F_ACC_RDONLY', 'H5P_DEFAULT');

%
% Open the named datatype.
%
filetype = H5T.open (file, DATATYPE);

%
% Output the data to the screen.
%
fprintf ('Named datatype: %s:\n', DATATYPE);

%
% Get datatype class.  If it isn't compound, we won't print
% anything.
%
typeclass = H5T.get_class (filetype);
if typeclass == H5ML.get_constant_value('H5T_COMPOUND')
    fprintf ('   Class: H5T_COMPOUND\n');
    nmembs = H5T.get_nmembers (filetype);
    
    %
    % Iterate over compound datatype members.
    %
    for i=1: nmembs
        %
        % Get the member name and print.
        %
        name = H5T.get_member_name (filetype, i-1);
        fprintf ('   %s\n', name);
    end
end

%
% Close and release resources.
%
H5T.close (filetype);
H5F.close (file);