Use error() rather than ::error() unless explicitly required. * resource-manager.cc (instance_ok), shortcut-manager.cc (instance_ok), daspk.cc (DASPK_ABORT, DASPK_ABORT2), dasrt.cc (DASRT_ABORT, DASRT_ABORT2), dassl.cc (DASSL_ABORT, DASSL_ABORT2), debug.cc (instance_ok), display.cc (instance_ok), dynamic-ld.cc (octave_shlib_list::instance_ok, octave_dynamic_loader::instance_ok, do_load_oct, do_load_mex), file-io.cc (fopen_mode_to_ios_mode, do_stream_open, Ffprintf, Fsprintf, Fscanf, Ffscanf, get_sscanf_data, Fsscanf, do_fread, do_fwrite, Fpopen, Ftempname, convert, Fumask), graphics.in.h (graphics_toolkit::instance_ok, gh_manager::instance_ok), load-path.cc (instance_ok), ls-oct-ascii.cc (save_three_d), lsode.cc (LSODE_ABORT, LSODE_ABORT2), oct-errno.in.cc (instance_ok), octave-link.cc (connect_link), pager.cc (octave_pager_stream::instance_ok, octave_diary_stream::instance_ok), quad.cc (QUAD_ABORT, QUAD_ABORT2), sighandlers.cc (w32_interrupt_manager::instance_ok, octave_child_list::instance_ok), symtab.cc (do_update_nest), symtab.h (instance_ok), syscalls.cc (convert), toplev.h (instance_ok), txt-eng-ft.cc (instance_ok, set_mode), urlwrite.cc (instance_ok), __init_fltk__.cc (instance_ok), ov-builtin.cc (do_multi_index_op), ov-classdef.cc (class_fevalStatic, make_class, octave_classdef::subsasgn, do_multi_index_op, cdef_object_array::subsref, cdef_object_array::subsasgn, install_meth, meta_subsref, run_constructor, make_meta_class, get_value, set_value, check_method), ov-classdef.h (meta_subsref, instance_ok), ov-fcn-handle.cc (octave_fcn_handle), ov-mex-fcn.cc (do_multi_index_op), ov-range.h (octave_range), ov-typeinfo.cc (instance_ok), ov-usr-fcn.cc (subsref, do_multi_index_op), pt-arg-list.cc (Fend, convert_to_const_vector), pt-cell.cc (rvalue1), pt-colon.cc (append, rvalue1), pt-eval.cc (visit_simple_for_command, visit_switch_command), pt-exp.cc (is_logically_true, rvalue), pt-id.cc (eval_undefined_error), pt-id.h (workspace_error), pt-mat.cc (get_concat_class): Use error() rather than ::error().

## Copyright (C) 2010, 2013 Martin Hepperle
##
## This file is part of Octave.
##
## Octave is free software; you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 3 of the License, or (at
## your option) any later version.
##
## Octave is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING.  If not, see
## <http://www.gnu.org/licenses/>.

## -*- texinfo -*-
## @deftypefn  {Function File} {@var{h} =} helpdlg (@var{msg})
## @deftypefnx {Function File} {@var{h} =} helpdlg (@var{msg}, @var{title})
## Display @var{msg} in a help dialog box.
##
## The message may have multiple lines separated by newline characters
## ("\n"), or it may be a cellstr array with one element for each
## line.
##
## The optional input @var{title} (character string) can be used to
## set the dialog caption.  The default title is @qcode{"Help Dialog"}.
##
## The return value is always 1.
## @seealso{errordlg, inputdlg, listdlg, msgbox, questdlg, warndlg}
## @end deftypefn

function retval = helpdlg (msg, title = "Help Dialog")

  if (nargin < 1 || nargin > 2)
    print_usage ();
  endif

  retval = message_dialog ("helpdlg", msg, title, "help");

endfunction


%!demo
%! disp ('- test helpdlg with a help message only.');
%! helpdlg ("Below, you should see 3 lines:\nline #1\nline #2, and\nline #3.");

%!demo
%! disp ('- test helpdlg with help message and caption.');
%! helpdlg ('You should see a single line.','A help dialog');