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| author | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
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| committer | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
| commit | abdaadbcae30fe0c9a66c7516798279fdfd97750 (patch) | |
| tree | 00a54a6e25601e43876d03c1a4a12a749d4a914c /share/doc/gcc/Method-signatures.html | |
https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads
Change-Id: I7303388733328cd98ab9aa3c30236db67f2e9e9c
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diff --git a/share/doc/gcc/Method-signatures.html b/share/doc/gcc/Method-signatures.html new file mode 100644 index 0000000..a588387 --- /dev/null +++ b/share/doc/gcc/Method-signatures.html @@ -0,0 +1,135 @@ +<!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): Method signatures</title> + +<meta name="description" content="Using the GNU Compiler Collection (GCC): Method signatures"> +<meta name="keywords" content="Using the GNU Compiler Collection (GCC): Method signatures"> +<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="Type-encoding.html#Type-encoding" rel="up" title="Type encoding"> +<link href="Garbage-Collection.html#Garbage-Collection" rel="next" title="Garbage Collection"> +<link href="_0040encode.html#g_t_0040encode" rel="previous" title="@encode"> +<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="Method-signatures"></a> +<div class="header"> +<p> +Previous: <a href="_0040encode.html#g_t_0040encode" accesskey="p" rel="previous">@encode</a>, Up: <a href="Type-encoding.html#Type-encoding" accesskey="u" rel="up">Type encoding</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="Method-Signatures"></a> +<h4 class="subsection">8.3.3 Method Signatures</h4> + +<p>This section documents the encoding of method types, which is rarely +needed to use Objective-C. You should skip it at a first reading; the +runtime provides functions that will work on methods and can walk +through the list of parameters and interpret them for you. These +functions are part of the public “API” and are the preferred way to +interact with method signatures from user code. +</p> +<p>But if you need to debug a problem with method signatures and need to +know how they are implemented (i.e., the “ABI”), read on. +</p> +<p>Methods have their “signature” encoded and made available to the +runtime. The “signature” encodes all the information required to +dynamically build invocations of the method at runtime: return type +and arguments. +</p> +<p>The “signature” is a null-terminated string, composed of the following: +</p> +<ul> +<li> The return type, including type qualifiers. For example, a method +returning <code>int</code> would have <code>i</code> here. + +</li><li> The total size (in bytes) required to pass all the parameters. This +includes the two hidden parameters (the object <code>self</code> and the +method selector <code>_cmd</code>). + +</li><li> Each argument, with the type encoding, followed by the offset (in +bytes) of the argument in the list of parameters. + +</li></ul> + +<p>For example, a method with no arguments and returning <code>int</code> would +have the signature <code>i8@0:4</code> if the size of a pointer is 4. The +signature is interpreted as follows: the <code>i</code> is the return type +(an <code>int</code>), the <code>8</code> is the total size of the parameters in +bytes (two pointers each of size 4), the <code>@0</code> is the first +parameter (an object at byte offset <code>0</code>) and <code>:4</code> is the +second parameter (a <code>SEL</code> at byte offset <code>4</code>). +</p> +<p>You can easily find more examples by running the “strings” program +on an Objective-C object file compiled by GCC. You’ll see a lot of +strings that look very much like <code>i8@0:4</code>. They are signatures +of Objective-C methods. +</p> + +<hr> +<div class="header"> +<p> +Previous: <a href="_0040encode.html#g_t_0040encode" accesskey="p" rel="previous">@encode</a>, Up: <a href="Type-encoding.html#Type-encoding" accesskey="u" rel="up">Type encoding</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> |