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106 lines
4.2 KiB
HTML
106 lines
4.2 KiB
HTML
4 years ago
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<!-- Copyright (C) 1988-2018 Free Software Foundation, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3 or
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any later version published by the Free Software Foundation; with the
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Invariant Sections being "Funding Free Software", the Front-Cover
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Texts being (a) (see below), and with the Back-Cover Texts being (b)
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(see below). A copy of the license is included in the section entitled
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"GNU Free Documentation License".
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(a) The FSF's Front-Cover Text is:
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A GNU Manual
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(b) The FSF's Back-Cover Text is:
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You have freedom to copy and modify this GNU Manual, like GNU
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software. Copies published by the Free Software Foundation raise
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funds for GNU development. -->
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<!-- Created by GNU Texinfo 6.4, http://www.gnu.org/software/texinfo/ -->
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<head>
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<title>Subscripting (Using the GNU Compiler Collection (GCC))</title>
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<meta name="description" content="Subscripting (Using the GNU Compiler Collection (GCC))">
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<meta name="keywords" content="Subscripting (Using the GNU Compiler Collection (GCC))">
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<meta name="resource-type" content="document">
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<meta name="distribution" content="global">
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<meta name="Generator" content="makeinfo">
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<link href="index.html#Top" rel="start" title="Top">
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<link href="Option-Index.html#Option-Index" rel="index" title="Option Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="C-Extensions.html#C-Extensions" rel="up" title="C Extensions">
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<link href="Pointer-Arith.html#Pointer-Arith" rel="next" title="Pointer Arith">
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<link href="Escaped-Newlines.html#Escaped-Newlines" rel="prev" title="Escaped Newlines">
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<style type="text/css">
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ul.no-bullet {list-style: none}
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-->
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</style>
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</head>
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<body lang="en">
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<a name="Subscripting"></a>
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<div class="header">
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<p>
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Next: <a href="Pointer-Arith.html#Pointer-Arith" accesskey="n" rel="next">Pointer Arith</a>, Previous: <a href="Escaped-Newlines.html#Escaped-Newlines" accesskey="p" rel="prev">Escaped Newlines</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>
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</div>
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<hr>
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<a name="Non_002dLvalue-Arrays-May-Have-Subscripts"></a>
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<h3 class="section">6.22 Non-Lvalue Arrays May Have Subscripts</h3>
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<a name="index-subscripting"></a>
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<a name="index-arrays_002c-non_002dlvalue"></a>
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<a name="index-subscripting-and-function-values"></a>
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<p>In ISO C99, arrays that are not lvalues still decay to pointers, and
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may be subscripted, although they may not be modified or used after
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the next sequence point and the unary ‘<samp>&</samp>’ operator may not be
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applied to them. As an extension, GNU C allows such arrays to be
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subscripted in C90 mode, though otherwise they do not decay to
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pointers outside C99 mode. For example,
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this is valid in GNU C though not valid in C90:
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</p>
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<div class="smallexample">
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<pre class="smallexample">struct foo {int a[4];};
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struct foo f();
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bar (int index)
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{
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return f().a[index];
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}
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</pre></div>
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</body>
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</html>
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