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108 lines
4.3 KiB
HTML
108 lines
4.3 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) 1987-2018 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. A copy of
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the license is included in the
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section entitled "GNU Free Documentation License".
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This manual contains no Invariant Sections. The Front-Cover Texts are
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(a) (see below), and the Back-Cover Texts are (b) (see below).
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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>Newlines in Arguments (The C Preprocessor)</title>
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<meta name="description" content="Newlines in Arguments (The C Preprocessor)">
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<meta name="keywords" content="Newlines in Arguments (The C Preprocessor)">
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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="Index-of-Directives.html#Index-of-Directives" rel="index" title="Index of Directives">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="Macro-Pitfalls.html#Macro-Pitfalls" rel="up" title="Macro Pitfalls">
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<link href="Conditionals.html#Conditionals" rel="next" title="Conditionals">
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<link href="Argument-Prescan.html#Argument-Prescan" rel="prev" title="Argument Prescan">
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<style type="text/css">
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<!--
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a.summary-letter {text-decoration: none}
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blockquote.indentedblock {margin-right: 0em}
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blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
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blockquote.smallquotation {font-size: smaller}
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div.display {margin-left: 3.2em}
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div.example {margin-left: 3.2em}
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div.lisp {margin-left: 3.2em}
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div.smalldisplay {margin-left: 3.2em}
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div.smalllisp {margin-left: 3.2em}
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kbd {font-style: oblique}
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pre.display {font-family: inherit}
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pre.format {font-family: inherit}
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pre.menu-comment {font-family: serif}
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pre.menu-preformatted {font-family: serif}
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pre.smalldisplay {font-family: inherit; font-size: smaller}
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pre.smallexample {font-size: smaller}
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pre.smalllisp {font-size: smaller}
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span.nolinebreak {white-space: nowrap}
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span.roman {font-family: initial; font-weight: normal}
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span.sansserif {font-family: sans-serif; font-weight: normal}
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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="Newlines-in-Arguments"></a>
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<div class="header">
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<p>
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Previous: <a href="Argument-Prescan.html#Argument-Prescan" accesskey="p" rel="prev">Argument Prescan</a>, Up: <a href="Macro-Pitfalls.html#Macro-Pitfalls" accesskey="u" rel="up">Macro Pitfalls</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index-of-Directives.html#Index-of-Directives" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<a name="Newlines-in-Arguments-1"></a>
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<h4 class="subsection">3.10.7 Newlines in Arguments</h4>
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<a name="index-newlines-in-macro-arguments"></a>
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<p>The invocation of a function-like macro can extend over many logical
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lines. However, in the present implementation, the entire expansion
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comes out on one line. Thus line numbers emitted by the compiler or
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debugger refer to the line the invocation started on, which might be
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different to the line containing the argument causing the problem.
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</p>
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<p>Here is an example illustrating this:
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</p>
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<div class="smallexample">
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<pre class="smallexample">#define ignore_second_arg(a,b,c) a; c
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ignore_second_arg (foo (),
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ignored (),
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syntax error);
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</pre></div>
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<p>The syntax error triggered by the tokens <code>syntax error</code> results in
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an error message citing line three—the line of ignore_second_arg—
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even though the problematic code comes from line five.
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</p>
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<p>We consider this a bug, and intend to fix it in the near future.
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</p>
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</body>
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</html>
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