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diff --git a/share/doc/gcc/Function-Attributes.html b/share/doc/gcc/Function-Attributes.html new file mode 100644 index 0000000..150bfb1 --- /dev/null +++ b/share/doc/gcc/Function-Attributes.html @@ -0,0 +1,225 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- This file documents the use of the GNU compilers. + +Copyright (C) 1988-2023 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 5.1, http://www.gnu.org/software/texinfo/ --> +<head> +<title>Using the GNU Compiler Collection (GCC): Function Attributes</title> + +<meta name="description" content="Using the GNU Compiler Collection (GCC): Function Attributes"> +<meta name="keywords" content="Using the GNU Compiler Collection (GCC): Function 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="Indices.html#Indices" rel="index" title="Indices"> +<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="Common-Function-Attributes.html#Common-Function-Attributes" rel="next" title="Common Function Attributes"> +<link href="Mixed-Labels-and-Declarations.html#Mixed-Labels-and-Declarations" rel="previous" title="Mixed Labels and Declarations"> +<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_US" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> +<a name="Function-Attributes"></a> +<div class="header"> +<p> +Next: <a href="Variable-Attributes.html#Variable-Attributes" accesskey="n" rel="next">Variable Attributes</a>, Previous: <a href="Mixed-Labels-and-Declarations.html#Mixed-Labels-and-Declarations" accesskey="p" rel="previous">Mixed Labels and Declarations</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="Indices.html#Indices" title="Index" rel="index">Index</a>]</p> +</div> +<hr> +<a name="Declaring-Attributes-of-Functions"></a> +<h3 class="section">6.33 Declaring Attributes of Functions</h3> +<a name="index-function-attributes"></a> +<a name="index-declaring-attributes-of-functions"></a> +<a name="index-volatile-applied-to-function"></a> +<a name="index-const-applied-to-function"></a> + +<p>In GNU C and C++, you can use function attributes to specify certain +function properties that may help the compiler optimize calls or +check code more carefully for correctness. For example, you +can use attributes to specify that a function never returns +(<code>noreturn</code>), returns a value depending only on the values of +its arguments (<code>const</code>), or has <code>printf</code>-style arguments +(<code>format</code>). +</p> +<p>You can also use attributes to control memory placement, code +generation options or call/return conventions within the function +being annotated. Many of these attributes are target-specific. For +example, many targets support attributes for defining interrupt +handler functions, which typically must follow special register usage +and return conventions. Such attributes are described in the subsection +for each target. However, a considerable number of attributes are +supported by most, if not all targets. Those are described in +the <a href="Common-Function-Attributes.html#Common-Function-Attributes">Common Function Attributes</a> section. +</p> +<p>Function attributes are introduced by the <code>__attribute__</code> keyword +in the declaration of a function, followed by an attribute specification +enclosed in double parentheses. You can specify multiple attributes in +a declaration by separating them by commas within the double parentheses +or by immediately following one attribute specification with another. +See <a href="Attribute-Syntax.html#Attribute-Syntax">Attribute Syntax</a>, for the exact rules on attribute syntax and +placement. Compatible attribute specifications on distinct declarations +of the same function are merged. An attribute specification that is not +compatible with attributes already applied to a declaration of the same +function is ignored with a warning. +</p> +<p>Some function attributes take one or more arguments that refer to +the function’s parameters by their positions within the function parameter +list. Such attribute arguments are referred to as <em>positional arguments</em>. +Unless specified otherwise, positional arguments that specify properties +of parameters with pointer types can also specify the same properties of +the implicit C++ <code>this</code> argument in non-static member functions, and +of parameters of reference to a pointer type. For ordinary functions, +position one refers to the first parameter on the list. In C++ non-static +member functions, position one refers to the implicit <code>this</code> pointer. +The same restrictions and effects apply to function attributes used with +ordinary functions or C++ member functions. +</p> +<p>GCC also supports attributes on +variable declarations (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>), +statements (see <a href="Statement-Attributes.html#Statement-Attributes">Statement Attributes</a>), +types (see <a href="Type-Attributes.html#Type-Attributes">Type Attributes</a>), +and on field declarations (for <code>tainted_args</code>). +</p> +<p>There is some overlap between the purposes of attributes and pragmas +(see <a href="Pragmas.html#Pragmas">Pragmas Accepted by GCC</a>). It has been +found convenient to use <code>__attribute__</code> to achieve a natural +attachment of attributes to their corresponding declarations, whereas +<code>#pragma</code> is of use for compatibility with other compilers +or constructs that do not naturally form part of the grammar. +</p> +<p>In addition to the attributes documented here, +GCC plugins may provide their own attributes. +</p> +<table class="menu" border="0" cellspacing="0"> +<tr><td align="left" valign="top">• <a href="Common-Function-Attributes.html#Common-Function-Attributes" accesskey="1">Common Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="AArch64-Function-Attributes.html#AArch64-Function-Attributes" accesskey="2">AArch64 Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="AMD-GCN-Function-Attributes.html#AMD-GCN-Function-Attributes" accesskey="3">AMD GCN Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="ARC-Function-Attributes.html#ARC-Function-Attributes" accesskey="4">ARC Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="ARM-Function-Attributes.html#ARM-Function-Attributes" accesskey="5">ARM Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="AVR-Function-Attributes.html#AVR-Function-Attributes" accesskey="6">AVR Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="Blackfin-Function-Attributes.html#Blackfin-Function-Attributes" accesskey="7">Blackfin Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="BPF-Function-Attributes.html#BPF-Function-Attributes" accesskey="8">BPF Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="C_002dSKY-Function-Attributes.html#C_002dSKY-Function-Attributes" accesskey="9">C-SKY Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="Epiphany-Function-Attributes.html#Epiphany-Function-Attributes">Epiphany Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="H8_002f300-Function-Attributes.html#H8_002f300-Function-Attributes">H8/300 Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="IA_002d64-Function-Attributes.html#IA_002d64-Function-Attributes">IA-64 Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="M32C-Function-Attributes.html#M32C-Function-Attributes">M32C Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="M32R_002fD-Function-Attributes.html#M32R_002fD-Function-Attributes">M32R/D Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="m68k-Function-Attributes.html#m68k-Function-Attributes">m68k Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="MCORE-Function-Attributes.html#MCORE-Function-Attributes">MCORE Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="MicroBlaze-Function-Attributes.html#MicroBlaze-Function-Attributes">MicroBlaze Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="Microsoft-Windows-Function-Attributes.html#Microsoft-Windows-Function-Attributes">Microsoft Windows Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="MIPS-Function-Attributes.html#MIPS-Function-Attributes">MIPS Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="MSP430-Function-Attributes.html#MSP430-Function-Attributes">MSP430 Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="NDS32-Function-Attributes.html#NDS32-Function-Attributes">NDS32 Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="Nios-II-Function-Attributes.html#Nios-II-Function-Attributes">Nios II Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="Nvidia-PTX-Function-Attributes.html#Nvidia-PTX-Function-Attributes">Nvidia PTX Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="PowerPC-Function-Attributes.html#PowerPC-Function-Attributes">PowerPC Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="RISC_002dV-Function-Attributes.html#RISC_002dV-Function-Attributes">RISC-V Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="RL78-Function-Attributes.html#RL78-Function-Attributes">RL78 Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="RX-Function-Attributes.html#RX-Function-Attributes">RX Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="S_002f390-Function-Attributes.html#S_002f390-Function-Attributes">S/390 Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="SH-Function-Attributes.html#SH-Function-Attributes">SH Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="Symbian-OS-Function-Attributes.html#Symbian-OS-Function-Attributes">Symbian OS Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="V850-Function-Attributes.html#V850-Function-Attributes">V850 Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="Visium-Function-Attributes.html#Visium-Function-Attributes">Visium Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="x86-Function-Attributes.html#x86-Function-Attributes">x86 Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="Xstormy16-Function-Attributes.html#Xstormy16-Function-Attributes">Xstormy16 Function Attributes</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +</table> + +<hr> +<div class="header"> +<p> +Next: <a href="Variable-Attributes.html#Variable-Attributes" accesskey="n" rel="next">Variable Attributes</a>, Previous: <a href="Mixed-Labels-and-Declarations.html#Mixed-Labels-and-Declarations" accesskey="p" rel="previous">Mixed Labels and Declarations</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="Indices.html#Indices" title="Index" rel="index">Index</a>]</p> +</div> + + + +</body> +</html> |