<html lang="en"> <head> <title>Comments and the Help System - GNU Octave</title> <meta http-equiv="Content-Type" content="text/html"> <meta name="description" content="GNU Octave"> <meta name="generator" content="makeinfo 4.13"> <link title="Top" rel="start" href="index.html#Top"> <link rel="up" href="Comments.html#Comments" title="Comments"> <link rel="prev" href="Block-Comments.html#Block-Comments" title="Block Comments"> <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> <meta http-equiv="Content-Style-Type" content="text/css"> <style type="text/css"><!-- pre.display { font-family:inherit } pre.format { font-family:inherit } pre.smalldisplay { font-family:inherit; font-size:smaller } pre.smallformat { font-family:inherit; font-size:smaller } pre.smallexample { font-size:smaller } pre.smalllisp { font-size:smaller } span.sc { font-variant:small-caps } span.roman { font-family:serif; font-weight:normal; } span.sansserif { font-family:sans-serif; font-weight:normal; } --></style> </head> <body> <div class="node"> <a name="Comments-and-the-Help-System"></a> <p> Previous: <a rel="previous" accesskey="p" href="Block-Comments.html#Block-Comments">Block Comments</a>, Up: <a rel="up" accesskey="u" href="Comments.html#Comments">Comments</a> <hr> </div> <h4 class="subsection">2.7.3 Comments and the Help System</h4> <p><a name="index-documenting-functions-193"></a><a name="index-documenting-user-scripts-194"></a><a name="index-help_002c-user_002ddefined-functions-195"></a> The <code>help</code> command (see <a href="Getting-Help.html#Getting-Help">Getting Help</a>) is able to find the first block of comments in a function and return those as a documentation string. This means that the same commands used to get help on built-in functions are available for properly formatted user-defined functions. For example, after defining the function <code>f</code> below, <pre class="example"> function xdot = f (x, t) # usage: f (x, t) # # This function defines the right-hand # side functions for a set of nonlinear # differential equations. r = 0.25; ... endfunction </pre> <p class="noindent">the command <kbd>help f</kbd> produces the output <pre class="example"> usage: f (x, t) This function defines the right-hand side functions for a set of nonlinear differential equations. </pre> <p>Although it is possible to put comment lines into keyboard-composed, throw-away Octave programs, it usually isn't very useful because the purpose of a comment is to help you or another person understand the program at a later time. <p>The <code>help</code> parser currently only recognizes single line comments (see <a href="Single-Line-Comments.html#Single-Line-Comments">Single Line Comments</a>) and not block comments for the initial help text. <!-- DO NOT EDIT! Generated automatically by munge-texi.pl. --> <!-- Copyright (C) 1996-2012 John W. Eaton --> <!-- 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/>. --> </body></html>