<html lang="en">
<head>
<title>Argp Help - The GNU C Library</title>
<meta http-equiv="Content-Type" content="text/html">
<meta name="description" content="The GNU C Library">
<meta name="generator" content="makeinfo 4.13">
<link title="Top" rel="start" href="index.html#Top">
<link rel="up" href="Argp.html#Argp" title="Argp">
<link rel="prev" href="Argp-Flags.html#Argp-Flags" title="Argp Flags">
<link rel="next" href="Argp-Examples.html#Argp-Examples" title="Argp Examples">
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
<!--
This file documents the GNU C library.

This is Edition 0.12, last updated 2007-10-27,
of `The GNU C Library Reference Manual', for version
2.8 (Sourcery G++ Lite 2011.03-41).

Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2001, 2002,
2003, 2007, 2008, 2010 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with the
Invariant Sections being ``Free Software Needs Free Documentation''
and ``GNU Lesser General Public License'', the Front-Cover texts being
``A GNU Manual'', and with the Back-Cover Texts as in (a) below.  A
copy of the license is included in the section entitled "GNU Free
Documentation License".

(a) The FSF's Back-Cover Text is: ``You have the freedom to
copy and modify this GNU manual.  Buying copies from the FSF
supports it in developing GNU and promoting software freedom.''-->
<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>
<link rel="stylesheet" type="text/css" href="../cs.css">
</head>
<body>
<div class="node">
<a name="Argp-Help"></a>
<p>
Next:&nbsp;<a rel="next" accesskey="n" href="Argp-Examples.html#Argp-Examples">Argp Examples</a>,
Previous:&nbsp;<a rel="previous" accesskey="p" href="Argp-Flags.html#Argp-Flags">Argp Flags</a>,
Up:&nbsp;<a rel="up" accesskey="u" href="Argp.html#Argp">Argp</a>
<hr>
</div>

<h4 class="subsection">25.3.9 The <code>argp_help</code> Function</h4>

<p>Normally programs using argp need not be written with particular
printing argument-usage-type help messages in mind as the standard
&lsquo;<samp><span class="samp">--help</span></samp>&rsquo; option is handled automatically by argp.  Typical error
cases can be handled using <code>argp_usage</code> and
<code>argp_error</code>.  See <a href="Argp-Helper-Functions.html#Argp-Helper-Functions">Argp Helper Functions</a>.  However, if it's
desirable to print a help message in some context other than parsing the
program options, argp offers the <code>argp_help</code> interface.

<!-- argp.h -->
<!-- GNU -->
<div class="defun">
&mdash; Function: void <b>argp_help</b> (<var>const struct argp *argp, FILE *stream, unsigned flags, char *name</var>)<var><a name="index-argp_005fhelp-3081"></a></var><br>
<blockquote><p>This outputs a help message for the argp parser <var>argp</var> to
<var>stream</var>.  The type of messages printed will be determined by
<var>flags</var>.

        <p>Any options such as &lsquo;<samp><span class="samp">--help</span></samp>&rsquo; that are implemented automatically by
argp itself will <em>not</em> be present in the help output; for this
reason it is best to use <code>argp_state_help</code> if calling from within
an argp parser function.  See <a href="Argp-Helper-Functions.html#Argp-Helper-Functions">Argp Helper Functions</a>. 
</p></blockquote></div>

<ul class="menu">
<li><a accesskey="1" href="Argp-Help-Flags.html#Argp-Help-Flags">Flags</a>:        Specifying what sort of help message to print. 
</ul>

   </body></html>