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<a name="Comments-and-the-Help-System"></a>
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<p>
Previous: <a href="Block-Comments.html#Block-Comments" accesskey="p" rel="prev">Block Comments</a>, Up: <a href="Comments.html#Comments" accesskey="u" rel="up">Comments</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
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<a name="Comments-and-the-Help-System-1"></a>
<h4 class="subsection">2.7.3 Comments and the Help System</h4>
<a name="index-documenting-functions"></a>
<a name="index-documenting-user-scripts"></a>
<a name="index-help_002c-user_002ddefined-functions"></a>
<p>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,
</p>
<div class="example">
<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></div>
<p>the command <kbd>help f</kbd> produces the output
</p>
<div class="example">
<pre class="example"> usage: f (x, t)
This function defines the right-hand
side functions for a set of nonlinear
differential equations.
</pre></div>
<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>
<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.
</p>
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