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135 lines
6.3 KiB
HTML
135 lines
6.3 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>Deprecated Features (Using the GNU Compiler Collection (GCC))</title>
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<meta name="description" content="Deprecated Features (Using the GNU Compiler Collection (GCC))">
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<meta name="keywords" content="Deprecated Features (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_002b_002b-Extensions.html#C_002b_002b-Extensions" rel="up" title="C++ Extensions">
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<link href="Backwards-Compatibility.html#Backwards-Compatibility" rel="next" title="Backwards Compatibility">
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<link href="C_002b_002b-Concepts.html#C_002b_002b-Concepts" rel="prev" title="C++ Concepts">
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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="Deprecated-Features"></a>
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<div class="header">
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<p>
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Next: <a href="Backwards-Compatibility.html#Backwards-Compatibility" accesskey="n" rel="next">Backwards Compatibility</a>, Previous: <a href="C_002b_002b-Concepts.html#C_002b_002b-Concepts" accesskey="p" rel="prev">C++ Concepts</a>, Up: <a href="C_002b_002b-Extensions.html#C_002b_002b-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="Deprecated-Features-1"></a>
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<h3 class="section">7.11 Deprecated Features</h3>
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<p>In the past, the GNU C++ compiler was extended to experiment with new
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features, at a time when the C++ language was still evolving. Now that
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the C++ standard is complete, some of those features are superseded by
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superior alternatives. Using the old features might cause a warning in
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some cases that the feature will be dropped in the future. In other
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cases, the feature might be gone already.
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</p>
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<p>While the list below is not exhaustive, it documents some of the options
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that are now deprecated or have been removed:
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</p>
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<dl compact="compact">
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<dt><code>-fno-for-scope</code></dt>
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<dt><code>-ffriend-injection</code></dt>
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<dd><p>These two options provide compatibility with pre-standard C++.
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See <a href="Backwards-Compatibility.html#Backwards-Compatibility">Backwards Compatibility</a>.
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</p>
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</dd>
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</dl>
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<p>G++ allows a virtual function returning ‘<samp>void *</samp>’ to be overridden
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by one returning a different pointer type. This extension to the
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covariant return type rules is now deprecated and will be removed from a
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future version.
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</p>
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<p>The use of default arguments in function pointers, function typedefs
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and other places where they are not permitted by the standard is
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deprecated and will be removed from a future version of G++.
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</p>
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<p>G++ allows floating-point literals to appear in integral constant expressions,
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e.g. ‘<samp> enum E { e = int(2.2 * 3.7) } </samp>’
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This extension is deprecated and will be removed from a future version.
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</p>
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<p>G++ allows static data members of const floating-point type to be declared
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with an initializer in a class definition. The standard only allows
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initializers for static members of const integral types and const
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enumeration types so this extension has been deprecated and will be removed
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from a future version.
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</p>
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<p>G++ allows attributes to follow a parenthesized direct initializer,
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e.g. ‘<samp> int f (0) __attribute__ ((something)); </samp>’ This extension
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has been ignored since G++ 3.3 and is deprecated.
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</p>
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<p>G++ allows anonymous structs and unions to have members that are not
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public non-static data members (i.e. fields). These extensions are
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deprecated.
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</p>
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<hr>
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<div class="header">
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<p>
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Next: <a href="Backwards-Compatibility.html#Backwards-Compatibility" accesskey="n" rel="next">Backwards Compatibility</a>, Previous: <a href="C_002b_002b-Concepts.html#C_002b_002b-Concepts" accesskey="p" rel="prev">C++ Concepts</a>, Up: <a href="C_002b_002b-Extensions.html#C_002b_002b-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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</body>
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</html>
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