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diff --git a/share/doc/gcc/Arrays-and-pointers-implementation.html b/share/doc/gcc/Arrays-and-pointers-implementation.html new file mode 100644 index 0000000..bd270d5 --- /dev/null +++ b/share/doc/gcc/Arrays-and-pointers-implementation.html @@ -0,0 +1,123 @@ +<!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): Arrays and pointers implementation</title> + +<meta name="description" content="Using the GNU Compiler Collection (GCC): Arrays and pointers implementation"> +<meta name="keywords" content="Using the GNU Compiler Collection (GCC): Arrays and pointers implementation"> +<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-Implementation.html#C-Implementation" rel="up" title="C Implementation"> +<link href="Hints-implementation.html#Hints-implementation" rel="next" title="Hints implementation"> +<link href="Floating-point-implementation.html#Floating-point-implementation" rel="previous" title="Floating point implementation"> +<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="Arrays-and-pointers-implementation"></a> +<div class="header"> +<p> +Next: <a href="Hints-implementation.html#Hints-implementation" accesskey="n" rel="next">Hints implementation</a>, Previous: <a href="Floating-point-implementation.html#Floating-point-implementation" accesskey="p" rel="previous">Floating point implementation</a>, Up: <a href="C-Implementation.html#C-Implementation" accesskey="u" rel="up">C Implementation</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="Arrays-and-Pointers"></a> +<h3 class="section">4.7 Arrays and Pointers</h3> + +<ul> +<li> <cite>The result of converting a pointer to an integer or +vice versa (C90 6.3.4, C99 and C11 6.3.2.3).</cite> + +<p>A cast from pointer to integer discards most-significant bits if the +pointer representation is larger than the integer type, +sign-extends<a name="DOCF5" href="#FOOT5"><sup>5</sup></a> +if the pointer representation is smaller than the integer type, otherwise +the bits are unchanged. +</p> +<p>A cast from integer to pointer discards most-significant bits if the +pointer representation is smaller than the integer type, extends according +to the signedness of the integer type if the pointer representation +is larger than the integer type, otherwise the bits are unchanged. +</p> +<p>When casting from pointer to integer and back again, the resulting +pointer must reference the same object as the original pointer, otherwise +the behavior is undefined. That is, one may not use integer arithmetic to +avoid the undefined behavior of pointer arithmetic as proscribed in +C99 and C11 6.5.6/8. +</p> +</li><li> <cite>The size of the result of subtracting two pointers to elements +of the same array (C90 6.3.6, C99 and C11 6.5.6).</cite> + +<p>The value is as specified in the standard and the type is determined +by the ABI. +</p> +</li></ul> + +<div class="footnote"> +<hr> +<h4 class="footnotes-heading">Footnotes</h4> + +<h3><a name="FOOT5" href="#DOCF5">(5)</a></h3> +<p>Future versions of GCC may zero-extend, or use +a target-defined <code>ptr_extend</code> pattern. Do not rely on sign extension.</p> +</div> + + + +</body> +</html> |