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117 lines
4.8 KiB
HTML
117 lines
4.8 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>Push/Pop Macro Pragmas (Using the GNU Compiler Collection (GCC))</title>
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<meta name="description" content="Push/Pop Macro Pragmas (Using the GNU Compiler Collection (GCC))">
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<meta name="keywords" content="Push/Pop Macro Pragmas (Using the GNU Compiler Collection (GCC))">
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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="Pragmas.html#Pragmas" rel="up" title="Pragmas">
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<link href="Function-Specific-Option-Pragmas.html#Function-Specific-Option-Pragmas" rel="next" title="Function Specific Option Pragmas">
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<link href="Visibility-Pragmas.html#Visibility-Pragmas" rel="prev" title="Visibility Pragmas">
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<style type="text/css">
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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="Push_002fPop-Macro-Pragmas"></a>
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<div class="header">
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<p>
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Next: <a href="Function-Specific-Option-Pragmas.html#Function-Specific-Option-Pragmas" accesskey="n" rel="next">Function Specific Option Pragmas</a>, Previous: <a href="Visibility-Pragmas.html#Visibility-Pragmas" accesskey="p" rel="prev">Visibility Pragmas</a>, Up: <a href="Pragmas.html#Pragmas" accesskey="u" rel="up">Pragmas</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="Push_002fPop-Macro-Pragmas-1"></a>
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<h4 class="subsection">6.61.14 Push/Pop Macro Pragmas</h4>
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<p>For compatibility with Microsoft Windows compilers, GCC supports
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‘<samp>#pragma push_macro(<var>"macro_name"</var>)</samp>’
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and ‘<samp>#pragma pop_macro(<var>"macro_name"</var>)</samp>’.
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</p>
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<dl compact="compact">
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<dt><code>#pragma push_macro(<var>"macro_name"</var>)</code></dt>
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<dd><a name="index-pragma_002c-push_005fmacro"></a>
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<p>This pragma saves the value of the macro named as <var>macro_name</var> to
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the top of the stack for this macro.
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</p>
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</dd>
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<dt><code>#pragma pop_macro(<var>"macro_name"</var>)</code></dt>
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<dd><a name="index-pragma_002c-pop_005fmacro"></a>
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<p>This pragma sets the value of the macro named as <var>macro_name</var> to
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the value on top of the stack for this macro. If the stack for
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<var>macro_name</var> is empty, the value of the macro remains unchanged.
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</p></dd>
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</dl>
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<p>For example:
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</p>
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<div class="smallexample">
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<pre class="smallexample">#define X 1
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#pragma push_macro("X")
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#undef X
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#define X -1
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#pragma pop_macro("X")
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int x [X];
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</pre></div>
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<p>In this example, the definition of X as 1 is saved by <code>#pragma
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push_macro</code> and restored by <code>#pragma pop_macro</code>.
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</p>
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</body>
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</html>
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