How to create a GUI inside a function in Matlab?

function myvar = myfunc()
    myvar = true;
    h_fig = figure;

    % create a useless button
    uicontrol( h_fig, 'style', 'pushbutton', ...
                      'string', 'clickme', ...
                      'callback', 'myvar = false' );

    % wait for the button to be pressed
    while myvar
        pause( 0.2 );
    end

    close( h_fig );

    disp( 'this will never be displayed' );
end

function make_useless_button()

  % Initialize variables and graphics:

  iCounter = 0;
  hFigure = figure;
  hButton = uicontrol('Style','pushbutton','Parent',hFigure,...
                      'String','Blah','Callback',@increment);

  function increment(source,event)
    iCounter = iCounter+1;
    disp(iCounter);
  end

end

function make_stop_button()

  % Initialize variables and graphics:

  keepLooping = true;
  hFigure = figure;
  hButton = uicontrol('Style','pushbutton','Parent',hFigure,...
                      'String','Stop','Callback',@stop_fcn);

  % Keep looping until button is pressed:

  while keepLooping,
    drawnow;
  end

  % Delete figure:

  delete(hFigure);

  % Nested callback:

  function stop_fcn(source,event)
    keepLooping = false;
  end

end

function myfunc()
    h_fig = figure;

    % add continue_loop to the GUI-handles structure
    fig_handles = guihandles( h_fig );
    fig_handles.continue_loop = true;
    guidata( h_fig, fig_handles );

    % create a useless button
    uicontrol( h_fig, 'style', 'pushbutton', ...
                      'string', 'clickme', ...
                      'callback', @gui_callback );

    % wait for the button to be pressed
    while fig_handles.continue_loop
    	fig_handles = guidata( h_fig ); % update handles
        pause( 0.2 );
    end

    close( h_fig );
    disp( 'callback ran successfully' );
end

% The arguments are the Matlab-defaults for GUI-callbacks.
function gui_callback( hObject, eventdata, handles )
    % modify and save handles-Structure
    handles.continue_loop = false;
    guidata( hObject, handles );
end