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Edit File: _0023line-Directive.html
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <!-- Created by GNU Texinfo 6.8, https://www.gnu.org/software/texinfo/ --> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <!-- This manual is for GNU Texinfo (version 6.8, 8 June 2021), a documentation system that can produce both online information and a printed manual from a single source using semantic markup. Copyright (C) 1988, 1990-1993, 1995-1999, 2001-2021 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License". --> <title>#line Directive (GNU Texinfo 6.8)</title> <meta name="description" content="#line Directive (GNU Texinfo 6.8)"> <meta name="keywords" content="#line Directive (GNU Texinfo 6.8)"> <meta name="resource-type" content="document"> <meta name="distribution" content="global"> <meta name="Generator" content="texi2any"> <meta name="viewport" content="width=device-width,initial-scale=1"> <link href="index.html" rel="start" title="Top"> <link href="Command-and-Variable-Index.html" rel="index" title="Command and Variable Index"> <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> <link href="External-Macro-Processors.html" rel="up" title="External Macro Processors"> <link href="_0023line-and-TeX.html" rel="next" title="#line and TeX"> <style type="text/css"> <!-- a.copiable-anchor {visibility: hidden; text-decoration: none; line-height: 0em} a.summary-letter {text-decoration: none} blockquote.indentedblock {margin-right: 0em} div.display {margin-left: 3.2em} div.example {margin-left: 3.2em} kbd {font-style: oblique} pre.display {font-family: inherit} pre.format {font-family: inherit} pre.menu-comment {font-family: serif} pre.menu-preformatted {font-family: serif} span.nolinebreak {white-space: nowrap} span.roman {font-family: initial; font-weight: normal} span.sansserif {font-family: sans-serif; font-weight: normal} span:hover a.copiable-anchor {visibility: visible} ul.no-bullet {list-style: none} --> </style> </head> <body lang="en"> <div class="subsection" id="g_t_0023line-Directive"> <div class="header"> <p> Next: <a href="_0023line-and-TeX.html" accesskey="n" rel="next">‘<samp>#line</samp>’ and TeX</a>, Up: <a href="External-Macro-Processors.html" accesskey="u" rel="up">External Macro Processors: Line Directives</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Command-and-Variable-Index.html" title="Index" rel="index">Index</a>]</p> </div> <hr> <span id="g_t_0023line-Directive-1"></span><h4 class="subsection">16.6.1 ‘<samp>#line</samp>’ Directive</h4> <span id="index-_0023line-directive"></span> <p>An input line such as this: </p> <div class="example"> <pre class="example">#line 100 "foo.ptexi" </pre></div> <p>indicates that the next line was line 100 of the file <samp>foo.ptexi</samp>, and so that’s what an error message should refer to. Both M4 (see <a data-manual="m4" href="../m4/Preprocessor-features.html#Preprocessor-features">Preprocessor features</a> in <cite>GNU M4</cite>) and CPP (see <a data-manual="cpp" href="../cpp/Line-Control.html#Line-Control">Line Control</a> in <cite>The C Preprocessor</cite>, and <a data-manual="cpp" href="../cpp/Preprocessor-Output.html#Preprocessor-Output">Preprocessor Output</a> in <cite>The C Preprocessor</cite>) can generate such lines. </p> <span id="index-CPP_005fLINE_005fDIRECTIVES"></span> <p>The <code>makeinfo</code> program recognizes these lines by default, except within <code>@verbatim</code> blocks (see <a href="_0040verbatim.html"><code>@verbatim</code>: Literal Text</a>). Their recognition can be turned off completely with <code>CPP_LINE_DIRECTIVES</code> (see <a href="Other-Customization-Variables.html">Other Customization Variables</a>), though there is normally no reason to do so. </p> <p>For those few programs (M4, CPP, Texinfo) which need to document ‘<samp>#line</samp>’ directives and therefore have examples which would otherwise match the pattern, the command <code>@hashchar{}</code> can be used (see <a href="Inserting-a-Hashsign.html">Inserting ‘#’ with <code>@hashchar{}</code></a>). The example line above looks like this in the source for this manual: </p> <div class="example"> <pre class="example">@hashchar{}line 100 "foo.ptexi" </pre></div> <p>The <code>@hashchar</code> command was added to Texinfo in 2013. If you don’t want to rely on it, you can also use <code>@set</code> and <code>@value</code> to insert the literal ‘<samp>#</samp>’: </p> <div class="example"> <pre class="example">@set hash # @value{hash}line 1 "example.c" </pre></div> <p>Or, if suitable, a <code>@verbatim</code> environment can be used instead of <code>@example</code>. As mentioned above, <code>#line</code>-recognition is disabled inside verbatim blocks. </p> </div> </body> </html>