toolchain/gcc-linaro-6.3.1-2017.02-x8.../share/doc/gcc/Enumerator-Attributes.html

122 lines
5.1 KiB
HTML
Raw Normal View History

2024-03-22 05:10:17 +00:00
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<!-- Copyright (C) 1988-2016 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; with the
Invariant Sections being "Funding Free Software", the Front-Cover
Texts being (a) (see below), and with the Back-Cover Texts being (b)
(see below). A copy of the license is included in the section entitled
"GNU Free Documentation License".
(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>Using the GNU Compiler Collection (GCC): Enumerator Attributes</title>
<meta name="description" content="Using the GNU Compiler Collection (GCC): Enumerator Attributes">
<meta name="keywords" content="Using the GNU Compiler Collection (GCC): Enumerator Attributes">
<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="Option-Index.html#Option-Index" rel="index" title="Option Index">
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
<link href="C-Extensions.html#C-Extensions" rel="up" title="C Extensions">
<link href="Attribute-Syntax.html#Attribute-Syntax" rel="next" title="Attribute Syntax">
<link href="Label-Attributes.html#Label-Attributes" rel="prev" title="Label Attributes">
<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="Enumerator-Attributes"></a>
<div class="header">
<p>
Next: <a href="Attribute-Syntax.html#Attribute-Syntax" accesskey="n" rel="next">Attribute Syntax</a>, Previous: <a href="Label-Attributes.html#Label-Attributes" accesskey="p" rel="prev">Label Attributes</a>, Up: <a href="C-Extensions.html#C-Extensions" accesskey="u" rel="up">C Extensions</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<a name="Enumerator-Attributes-1"></a>
<h3 class="section">6.35 Enumerator Attributes</h3>
<a name="index-Enumerator-Attributes"></a>
<p>GCC allows attributes to be set on enumerators. See <a href="Attribute-Syntax.html#Attribute-Syntax">Attribute Syntax</a>, for
details of the exact syntax for using attributes. Other attributes are
available for functions (see <a href="Function-Attributes.html#Function-Attributes">Function Attributes</a>), variables
(see <a href="Variable-Attributes.html#Variable-Attributes">Variable Attributes</a>), labels (see <a href="Label-Attributes.html#Label-Attributes">Label Attributes</a>),
and for types (see <a href="Type-Attributes.html#Type-Attributes">Type Attributes</a>).
</p>
<p>This example uses the <code>deprecated</code> enumerator attribute to indicate the
<code>oldval</code> enumerator is deprecated:
</p>
<div class="smallexample">
<pre class="smallexample">enum E {
oldval __attribute__((deprecated)),
newval
};
int
fn (void)
{
return oldval;
}
</pre></div>
<dl compact="compact">
<dt><code>deprecated</code></dt>
<dd><a name="index-deprecated-enumerator-attribute"></a>
<p>The <code>deprecated</code> attribute results in a warning if the enumerator
is used anywhere in the source file. This is useful when identifying
enumerators that are expected to be removed in a future version of a
program. The warning also includes the location of the declaration
of the deprecated enumerator, to enable users to easily find further
information about why the enumerator is deprecated, or what they should
do instead. Note that the warnings only occurs for uses.
</p>
</dd>
</dl>
</body>
</html>