You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
122 lines
5.3 KiB
HTML
122 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) 1988-2018 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 6.4, http://www.gnu.org/software/texinfo/ -->
|
|
<head>
|
|
<title>Statement Attributes (Using the GNU Compiler Collection (GCC))</title>
|
|
|
|
<meta name="description" content="Statement Attributes (Using the GNU Compiler Collection (GCC))">
|
|
<meta name="keywords" content="Statement Attributes (Using the GNU Compiler Collection (GCC))">
|
|
<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="Enumerator-Attributes.html#Enumerator-Attributes" rel="prev" title="Enumerator Attributes">
|
|
<style type="text/css">
|
|
<!--
|
|
a.summary-letter {text-decoration: none}
|
|
blockquote.indentedblock {margin-right: 0em}
|
|
blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
|
|
blockquote.smallquotation {font-size: smaller}
|
|
div.display {margin-left: 3.2em}
|
|
div.example {margin-left: 3.2em}
|
|
div.lisp {margin-left: 3.2em}
|
|
div.smalldisplay {margin-left: 3.2em}
|
|
div.smallexample {margin-left: 3.2em}
|
|
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.nolinebreak {white-space: nowrap}
|
|
span.roman {font-family: initial; font-weight: normal}
|
|
span.sansserif {font-family: sans-serif; font-weight: normal}
|
|
ul.no-bullet {list-style: none}
|
|
-->
|
|
</style>
|
|
|
|
|
|
</head>
|
|
|
|
<body lang="en">
|
|
<a name="Statement-Attributes"></a>
|
|
<div class="header">
|
|
<p>
|
|
Next: <a href="Attribute-Syntax.html#Attribute-Syntax" accesskey="n" rel="next">Attribute Syntax</a>, Previous: <a href="Enumerator-Attributes.html#Enumerator-Attributes" accesskey="p" rel="prev">Enumerator Attributes</a>, Up: <a href="C-Extensions.html#C-Extensions" accesskey="u" rel="up">C Extensions</a> [<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="Statement-Attributes-1"></a>
|
|
<h3 class="section">6.36 Statement Attributes</h3>
|
|
<a name="index-Statement-Attributes"></a>
|
|
|
|
<p>GCC allows attributes to be set on null statements. 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>), enumerators
|
|
(see <a href="Enumerator-Attributes.html#Enumerator-Attributes">Enumerator Attributes</a>), and for types (see <a href="Type-Attributes.html#Type-Attributes">Type Attributes</a>).
|
|
</p>
|
|
<p>This example uses the <code>fallthrough</code> statement attribute to indicate that
|
|
the <samp>-Wimplicit-fallthrough</samp> warning should not be emitted:
|
|
</p>
|
|
<div class="smallexample">
|
|
<pre class="smallexample">switch (cond)
|
|
{
|
|
case 1:
|
|
bar (1);
|
|
__attribute__((fallthrough));
|
|
case 2:
|
|
…
|
|
}
|
|
</pre></div>
|
|
|
|
<dl compact="compact">
|
|
<dt><code>fallthrough</code></dt>
|
|
<dd><a name="index-fallthrough-statement-attribute"></a>
|
|
<p>The <code>fallthrough</code> attribute with a null statement serves as a
|
|
fallthrough statement. It hints to the compiler that a statement
|
|
that falls through to another case label, or user-defined label
|
|
in a switch statement is intentional and thus the
|
|
<samp>-Wimplicit-fallthrough</samp> warning must not trigger. The
|
|
fallthrough attribute may appear at most once in each attribute
|
|
list, and may not be mixed with other attributes. It can only
|
|
be used in a switch statement (the compiler will issue an error
|
|
otherwise), after a preceding statement and before a logically
|
|
succeeding case label, or user-defined label.
|
|
</p>
|
|
</dd>
|
|
</dl>
|
|
|
|
|
|
|
|
|
|
</body>
|
|
</html>
|