function display_help(funct,field)% Displays instructions found in a text file with name ['help4',funct,'.txt'] % in subdirectory "HelpFiles" in directory S4M.myseislab%% Written by: E. R.: December 20, 2005% Last updated:%%         display_help(funct,field)% INPUT% funct   string with name of function that creates the plot for which the %         button is intended% field   field of the help structure which contains the help message%         (not used if the help structure read from the text file has only one field)global S4M%	Check if a help file existsfilename=fullfile(S4M.myseislab,'HelpFiles',['help4',funct,'.txt']);fid=fopen(filename);if fid < 0   alert(['Help file for "',funct,'" has not been found. No help message will be shown.'])   returnend%	Read help file and save its content in structure "help_info".help_info=get_help_file(fid);%	Determine the number of sub-menus (if any)fields=fieldnames(help_info);if length(fields) == 1	% Only one message   temp=getfield(help_info,fields{1});   helpdlg(temp,S4M.name)else   if nargin < 2      error('No message field specified.')   end   try      temp=getfield(help_info,field);   catch      disp(help_info)      if ischar(field)         error(['Requested field of "help_info" ("',field,'") not found.'])      else         error('Second input argument is not a character string.')      end   end   helpdlg(temp,S4M.name)end