<html lang="en">
<head>
<title>Conditional Syntax - The C Preprocessor</title>
<meta http-equiv="Content-Type" content="text/html">
<meta name="description" content="The C Preprocessor">
<meta name="generator" content="makeinfo 4.13">
<link title="Top" rel="start" href="index.html#Top">
<link rel="up" href="Conditionals.html#Conditionals" title="Conditionals">
<link rel="prev" href="Conditional-Uses.html#Conditional-Uses" title="Conditional Uses">
<link rel="next" href="Deleted-Code.html#Deleted-Code" title="Deleted Code">
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
<!--
Copyright (C) 1987-2015 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. A copy of
the license is included in the
section entitled ``GNU Free Documentation License''.
This manual contains no Invariant Sections. The Front-Cover Texts are
(a) (see below), and the Back-Cover Texts are (b) (see below).
(a) The FSF's Front-Cover Text is:
A GNU Manual
(b) The FSF's Back-Cover Text is:
You have freedom to copy and modify this GNU Manual, like GNU
software. Copies published by the Free Software Foundation raise
funds for GNU development.
-->
<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="Conditional-Syntax"></a>
<p>
Next: <a rel="next" accesskey="n" href="Deleted-Code.html#Deleted-Code">Deleted Code</a>,
Previous: <a rel="previous" accesskey="p" href="Conditional-Uses.html#Conditional-Uses">Conditional Uses</a>,
Up: <a rel="up" accesskey="u" href="Conditionals.html#Conditionals">Conditionals</a>
<hr>
</div>
<h3 class="section">4.2 Conditional Syntax</h3>
<p><a name="index-g_t_0023if-84"></a>A conditional in the C preprocessor begins with a <dfn>conditional
directive</dfn>: ‘<samp><span class="samp">#if</span></samp>’, ‘<samp><span class="samp">#ifdef</span></samp>’ or ‘<samp><span class="samp">#ifndef</span></samp>’.
<ul class="menu">
<li><a accesskey="1" href="Ifdef.html#Ifdef">Ifdef</a>
<li><a accesskey="2" href="If.html#If">If</a>
<li><a accesskey="3" href="Defined.html#Defined">Defined</a>
<li><a accesskey="4" href="Else.html#Else">Else</a>
<li><a accesskey="5" href="Elif.html#Elif">Elif</a>
</ul>
</body></html>