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| 21 | <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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| 22 | <title>Line Continuation (GNU C Language Manual)</title>
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| 23 |
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| 24 | <meta name="description" content="Line Continuation (GNU C Language Manual)">
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| 30 | <link href="Symbol-Index.html" rel="index" title="Symbol Index">
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| 31 | <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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| 32 | <link href="Lexical-Syntax.html" rel="up" title="Lexical Syntax">
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| 33 | <link href="Arithmetic.html" rel="next" title="Arithmetic">
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| 34 | <link href="Operators_002fPunctuation.html" rel="prev" title="Operators/Punctuation">
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| 57 | <body lang="en">
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| 58 | <span id="Line-Continuation"></span><div class="header">
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| 59 | <p>
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| 60 | Previous: <a href="Operators_002fPunctuation.html" accesskey="p" rel="prev">Operators/Punctuation</a>, Up: <a href="Lexical-Syntax.html" accesskey="u" rel="up">Lexical Syntax</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Symbol-Index.html" title="Index" rel="index">Index</a>]</p>
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| 61 | </div>
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| 62 | <hr>
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| 63 | <span id="Line-Continuation-1"></span><h3 class="section">5.7 Line Continuation</h3>
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| 64 | <span id="index-line-continuation"></span>
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| 65 | <span id="index-continuation-of-lines"></span>
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| 66 |
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| 67 | <p>The sequence of a backslash and a newline is ignored absolutely
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| 68 | anywhere in a C program. This makes it possible to split a single
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| 69 | source line into multiple lines in the source file. GNU C tolerates
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| 70 | and ignores other whitespace between the backslash and the newline.
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| 71 | In particular, it always ignores a CR (carriage return) character
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| 72 | there, in case some text editor decided to end the line with the CRLF
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| 73 | sequence.
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| 74 | </p>
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| 75 | <p>The main use of line continuation in C is for macro definitions that
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| 76 | would be inconveniently long for a single line (see <a href="Macros.html">Macros</a>).
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| 77 | </p>
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| 78 | <p>It is possible to continue a line comment onto another line with
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| 79 | backslash-newline. You can put backslash-newline in the middle of an
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| 80 | identifier, even a keyword, or an operator. You can even split
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| 81 | ‘<samp>/*</samp>’, ‘<samp>*/</samp>’, and ‘<samp>//</samp>’ onto multiple lines with
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| 82 | backslash-newline. Here’s an ugly example:
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| 83 | </p>
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| 84 | <div class="example">
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| 85 | <pre class="example">/\
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| 86 | *
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| 87 | */ fo\
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| 88 | o +\
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| 89 | = 1\
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| 90 | 0;
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| 91 | </pre></div>
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| 92 |
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| 93 | <p>That’s equivalent to ‘<samp>/* */ foo += 10;</samp>’.
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| 94 | </p>
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| 95 | <p>Don’t do those things in real programs, since they make code hard to
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| 96 | read.
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| 97 | </p>
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| 98 | <p><strong>Note:</strong> For the sake of using certain tools on the source code, it is
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| 99 | wise to end every source file with a newline character which is not
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| 100 | preceded by a backslash, so that it really ends the last line.
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| 101 | </p>
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| 102 |
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| 103 |
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| 104 |
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| 105 | </body>
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| 106 | </html>
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