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diff --git a/share/doc/cpp/Preprocessor-Output.html b/share/doc/cpp/Preprocessor-Output.html new file mode 100644 index 0000000..7ee5fcd --- /dev/null +++ b/share/doc/cpp/Preprocessor-Output.html @@ -0,0 +1,164 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- Copyright (C) 1987-2023 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. A copy of +the license is included in the +section entitled "GNU Free Documentation License". + +This manual contains no Invariant Sections. The Front-Cover Texts are +(a) (see below), and the Back-Cover Texts are (b) (see below). + +(a) The FSF's Front-Cover Text is: + +A GNU Manual + +(b) The FSF's Back-Cover Text is: + +You have freedom to copy and modify this GNU Manual, like GNU + software. Copies published by the Free Software Foundation raise + funds for GNU development. --> +<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ --> +<head> +<title>The C Preprocessor: Preprocessor Output</title> + +<meta name="description" content="The C Preprocessor: Preprocessor Output"> +<meta name="keywords" content="The C Preprocessor: Preprocessor Output"> +<meta name="resource-type" content="document"> +<meta name="distribution" content="global"> +<meta name="Generator" content="makeinfo"> +<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> +<link href="index.html#Top" rel="start" title="Top"> +<link href="Index-of-Directives.html#Index-of-Directives" rel="index" title="Index of Directives"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="index.html#Top" rel="up" title="Top"> +<link href="Traditional-Mode.html#Traditional-Mode" rel="next" title="Traditional Mode"> +<link href="Other-Directives.html#Other-Directives" rel="previous" title="Other Directives"> +<style type="text/css"> +<!-- +a.summary-letter {text-decoration: none} +blockquote.smallquotation {font-size: smaller} +div.display {margin-left: 3.2em} +div.example {margin-left: 3.2em} +div.indentedblock {margin-left: 3.2em} +div.lisp {margin-left: 3.2em} +div.smalldisplay {margin-left: 3.2em} +div.smallexample {margin-left: 3.2em} +div.smallindentedblock {margin-left: 3.2em; font-size: smaller} +div.smalllisp {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} +pre.smalldisplay {font-family: inherit; font-size: smaller} +pre.smallexample {font-size: smaller} +pre.smallformat {font-family: inherit; font-size: smaller} +pre.smalllisp {font-size: smaller} +span.nocodebreak {white-space:nowrap} +span.nolinebreak {white-space:nowrap} +span.roman {font-family:serif; font-weight:normal} +span.sansserif {font-family:sans-serif; font-weight:normal} +ul.no-bullet {list-style: none} +--> +</style> + + +</head> + +<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> +<a name="Preprocessor-Output"></a> +<div class="header"> +<p> +Next: <a href="Traditional-Mode.html#Traditional-Mode" accesskey="n" rel="next">Traditional Mode</a>, Previous: <a href="Other-Directives.html#Other-Directives" accesskey="p" rel="previous">Other Directives</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</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> +</div> +<hr> +<a name="Preprocessor-Output-1"></a> +<h2 class="chapter">9 Preprocessor Output</h2> + +<p>When the C preprocessor is used with the C, C++, or Objective-C +compilers, it is integrated into the compiler and communicates a stream +of binary tokens directly to the compiler’s parser. However, it can +also be used in the more conventional standalone mode, where it produces +textual output. +</p> +<a name="index-output-format"></a> +<p>The output from the C preprocessor looks much like the input, except +that all preprocessing directive lines have been replaced with blank +lines and all comments with spaces. Long runs of blank lines are +discarded. +</p> +<p>The ISO standard specifies that it is implementation defined whether a +preprocessor preserves whitespace between tokens, or replaces it with +e.g. a single space. In GNU CPP, whitespace between tokens is collapsed +to become a single space, with the exception that the first token on a +non-directive line is preceded with sufficient spaces that it appears in +the same column in the preprocessed output that it appeared in the +original source file. This is so the output is easy to read. +CPP does not insert any +whitespace where there was none in the original source, except where +necessary to prevent an accidental token paste. +</p> +<a name="index-linemarkers"></a> +<p>Source file name and line number information is conveyed by lines +of the form +</p> +<div class="smallexample"> +<pre class="smallexample"># <var>linenum</var> <var>filename</var> <var>flags</var> +</pre></div> + +<p>These are called <em>linemarkers</em>. They are inserted as needed into +the output (but never within a string or character constant). They mean +that the following line originated in file <var>filename</var> at line +<var>linenum</var>. <var>filename</var> will never contain any non-printing +characters; they are replaced with octal escape sequences. +</p> +<p>After the file name comes zero or more flags, which are ‘<samp>1</samp>’, +‘<samp>2</samp>’, ‘<samp>3</samp>’, or ‘<samp>4</samp>’. If there are multiple flags, spaces +separate them. Here is what the flags mean: +</p> +<dl compact="compact"> +<dt>‘<samp>1</samp>’</dt> +<dd><p>This indicates the start of a new file. +</p></dd> +<dt>‘<samp>2</samp>’</dt> +<dd><p>This indicates returning to a file (after having included another file). +</p></dd> +<dt>‘<samp>3</samp>’</dt> +<dd><p>This indicates that the following text comes from a system header file, +so certain warnings should be suppressed. +</p></dd> +<dt>‘<samp>4</samp>’</dt> +<dd><p>This indicates that the following text should be treated as being +wrapped in an implicit <code>extern "C"</code> block. +</p></dd> +</dl> + +<p>As an extension, the preprocessor accepts linemarkers in non-assembler +input files. They are treated like the corresponding ‘<samp>#line</samp>’ +directive, (see <a href="Line-Control.html#Line-Control">Line Control</a>), except that trailing flags are +permitted, and are interpreted with the meanings described above. If +multiple flags are given, they must be in ascending order. +</p> +<p>Some directives may be duplicated in the output of the preprocessor. +These are ‘<samp>#ident</samp>’ (always), ‘<samp>#pragma</samp>’ (only if the +preprocessor does not handle the pragma itself), and ‘<samp>#define</samp>’ and +‘<samp>#undef</samp>’ (with certain debugging options). If this happens, the +‘<samp>#</samp>’ of the directive will always be in the first column, and there +will be no space between the ‘<samp>#</samp>’ and the directive name. If macro +expansion happens to generate tokens which might be mistaken for a +duplicated directive, a space will be inserted between the ‘<samp>#</samp>’ and +the directive name. +</p> +<hr> +<div class="header"> +<p> +Next: <a href="Traditional-Mode.html#Traditional-Mode" accesskey="n" rel="next">Traditional Mode</a>, Previous: <a href="Other-Directives.html#Other-Directives" accesskey="p" rel="previous">Other Directives</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</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> +</div> + + + +</body> +</html> |