121 lines
5.3 KiB
HTML
121 lines
5.3 KiB
HTML
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||
|
|
<html>
|
||
|
|
<!-- Copyright (C) 1987-2016 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. -->
|
||
|
|
<!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ -->
|
||
|
|
<head>
|
||
|
|
<title>The C Preprocessor: Include Syntax</title>
|
||
|
|
|
||
|
|
<meta name="description" content="The C Preprocessor: Include Syntax">
|
||
|
|
<meta name="keywords" content="The C Preprocessor: Include Syntax">
|
||
|
|
<meta name="resource-type" content="document">
|
||
|
|
<meta name="distribution" content="global">
|
||
|
|
<meta name="Generator" content="makeinfo">
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
||
|
|
<link href="index.html#Top" rel="start" title="Top">
|
||
|
|
<link href="Index-of-Directives.html#Index-of-Directives" rel="index" title="Index of Directives">
|
||
|
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
||
|
|
<link href="Header-Files.html#Header-Files" rel="up" title="Header Files">
|
||
|
|
<link href="Include-Operation.html#Include-Operation" rel="next" title="Include Operation">
|
||
|
|
<link href="Header-Files.html#Header-Files" rel="prev" title="Header Files">
|
||
|
|
<style type="text/css">
|
||
|
|
<!--
|
||
|
|
a.summary-letter {text-decoration: none}
|
||
|
|
blockquote.smallquotation {font-size: smaller}
|
||
|
|
div.display {margin-left: 3.2em}
|
||
|
|
div.example {margin-left: 3.2em}
|
||
|
|
div.indentedblock {margin-left: 3.2em}
|
||
|
|
div.lisp {margin-left: 3.2em}
|
||
|
|
div.smalldisplay {margin-left: 3.2em}
|
||
|
|
div.smallexample {margin-left: 3.2em}
|
||
|
|
div.smallindentedblock {margin-left: 3.2em; font-size: smaller}
|
||
|
|
div.smalllisp {margin-left: 3.2em}
|
||
|
|
kbd {font-style:oblique}
|
||
|
|
pre.display {font-family: inherit}
|
||
|
|
pre.format {font-family: inherit}
|
||
|
|
pre.menu-comment {font-family: serif}
|
||
|
|
pre.menu-preformatted {font-family: serif}
|
||
|
|
pre.smalldisplay {font-family: inherit; font-size: smaller}
|
||
|
|
pre.smallexample {font-size: smaller}
|
||
|
|
pre.smallformat {font-family: inherit; font-size: smaller}
|
||
|
|
pre.smalllisp {font-size: smaller}
|
||
|
|
span.nocodebreak {white-space:nowrap}
|
||
|
|
span.nolinebreak {white-space:nowrap}
|
||
|
|
span.roman {font-family:serif; font-weight:normal}
|
||
|
|
span.sansserif {font-family:sans-serif; font-weight:normal}
|
||
|
|
ul.no-bullet {list-style: none}
|
||
|
|
-->
|
||
|
|
</style>
|
||
|
|
|
||
|
|
|
||
|
|
</head>
|
||
|
|
|
||
|
|
<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
|
||
|
|
<a name="Include-Syntax"></a>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Next: <a href="Include-Operation.html#Include-Operation" accesskey="n" rel="next">Include Operation</a>, Up: <a href="Header-Files.html#Header-Files" accesskey="u" rel="up">Header Files</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index-of-Directives.html#Index-of-Directives" title="Index" rel="index">Index</a>]</p>
|
||
|
|
</div>
|
||
|
|
<hr>
|
||
|
|
<a name="Include-Syntax-1"></a>
|
||
|
|
<h3 class="section">2.1 Include Syntax</h3>
|
||
|
|
|
||
|
|
<a name="index-_0023include"></a>
|
||
|
|
<p>Both user and system header files are included using the preprocessing
|
||
|
|
directive ‘<samp>#include</samp>’. It has two variants:
|
||
|
|
</p>
|
||
|
|
<dl compact="compact">
|
||
|
|
<dt><code>#include <<var>file</var>></code></dt>
|
||
|
|
<dd><p>This variant is used for system header files. It searches for a file
|
||
|
|
named <var>file</var> in a standard list of system directories. You can prepend
|
||
|
|
directories to this list with the <samp>-I</samp> option (see <a href="Invocation.html#Invocation">Invocation</a>).
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>#include "<var>file</var>"</code></dt>
|
||
|
|
<dd><p>This variant is used for header files of your own program. It
|
||
|
|
searches for a file named <var>file</var> first in the directory containing
|
||
|
|
the current file, then in the quote directories and then the same
|
||
|
|
directories used for <code><<var>file</var>></code>. You can prepend directories
|
||
|
|
to the list of quote directories with the <samp>-iquote</samp> option.
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<p>The argument of ‘<samp>#include</samp>’, whether delimited with quote marks or
|
||
|
|
angle brackets, behaves like a string constant in that comments are not
|
||
|
|
recognized, and macro names are not expanded. Thus, <code>#include <x/*y><!-- /@w --></code> specifies inclusion of a system header file named <samp>x/*y</samp>.
|
||
|
|
</p>
|
||
|
|
<p>However, if backslashes occur within <var>file</var>, they are considered
|
||
|
|
ordinary text characters, not escape characters. None of the character
|
||
|
|
escape sequences appropriate to string constants in C are processed.
|
||
|
|
Thus, <code>#include "x\n\\y"<!-- /@w --></code> specifies a filename containing three
|
||
|
|
backslashes. (Some systems interpret ‘<samp>\</samp>’ as a pathname separator.
|
||
|
|
All of these also interpret ‘<samp>/</samp>’ the same way. It is most portable
|
||
|
|
to use only ‘<samp>/</samp>’.)
|
||
|
|
</p>
|
||
|
|
<p>It is an error if there is anything (other than comments) on the line
|
||
|
|
after the file name.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|