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diff --git a/share/doc/cpp/Overview.html b/share/doc/cpp/Overview.html new file mode 100644 index 0000000..f7b8a91 --- /dev/null +++ b/share/doc/cpp/Overview.html @@ -0,0 +1,148 @@ +<!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: Overview</title> + +<meta name="description" content="The C Preprocessor: Overview"> +<meta name="keywords" content="The C Preprocessor: Overview"> +<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="Character-sets.html#Character-sets" rel="next" title="Character sets"> +<link href="index.html#Top" rel="previous" title="Top"> +<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="Overview"></a> +<div class="header"> +<p> +Next: <a href="Header-Files.html#Header-Files" accesskey="n" rel="next">Header Files</a>, Previous: <a href="index.html#Top" accesskey="p" rel="previous">Top</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="Overview-1"></a> +<h2 class="chapter">1 Overview</h2> +<p>The C preprocessor, often known as <em>cpp</em>, is a <em>macro processor</em> +that is used automatically by the C compiler to transform your program +before compilation. It is called a macro processor because it allows +you to define <em>macros</em>, which are brief abbreviations for longer +constructs. +</p> +<p>The C preprocessor is intended to be used only with C, C++, and +Objective-C source code. In the past, it has been abused as a general +text processor. It will choke on input which does not obey C’s lexical +rules. For example, apostrophes will be interpreted as the beginning of +character constants, and cause errors. Also, you cannot rely on it +preserving characteristics of the input which are not significant to +C-family languages. If a Makefile is preprocessed, all the hard tabs +will be removed, and the Makefile will not work. +</p> +<p>Having said that, you can often get away with using cpp on things which +are not C. Other Algol-ish programming languages are often safe +(Ada, etc.) So is assembly, with caution. <samp>-traditional-cpp</samp> +mode preserves more white space, and is otherwise more permissive. Many +of the problems can be avoided by writing C or C++ style comments +instead of native language comments, and keeping macros simple. +</p> +<p>Wherever possible, you should use a preprocessor geared to the language +you are writing in. Modern versions of the GNU assembler have macro +facilities. Most high level programming languages have their own +conditional compilation and inclusion mechanism. If all else fails, +try a true general text processor, such as GNU M4. +</p> +<p>C preprocessors vary in some details. This manual discusses the GNU C +preprocessor, which provides a small superset of the features of ISO +Standard C. In its default mode, the GNU C preprocessor does not do a +few things required by the standard. These are features which are +rarely, if ever, used, and may cause surprising changes to the meaning +of a program which does not expect them. To get strict ISO Standard C, +you should use the <samp>-std=c90</samp>, <samp>-std=c99</samp>, +<samp>-std=c11</samp> or <samp>-std=c17</samp> options, depending +on which version of the standard you want. To get all the mandatory +diagnostics, you must also use <samp>-pedantic</samp>. See <a href="Invocation.html#Invocation">Invocation</a>. +</p> +<p>This manual describes the behavior of the ISO preprocessor. To +minimize gratuitous differences, where the ISO preprocessor’s +behavior does not conflict with traditional semantics, the +traditional preprocessor should behave the same way. The various +differences that do exist are detailed in the section <a href="Traditional-Mode.html#Traditional-Mode">Traditional Mode</a>. +</p> +<p>For clarity, unless noted otherwise, references to ‘<samp>CPP</samp>’ in this +manual refer to GNU CPP. +</p> +<table class="menu" border="0" cellspacing="0"> +<tr><td align="left" valign="top">• <a href="Character-sets.html#Character-sets" accesskey="1">Character sets</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="Initial-processing.html#Initial-processing" accesskey="2">Initial processing</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="Tokenization.html#Tokenization" accesskey="3">Tokenization</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +<tr><td align="left" valign="top">• <a href="The-preprocessing-language.html#The-preprocessing-language" accesskey="4">The preprocessing language</a>:</td><td> </td><td align="left" valign="top"> +</td></tr> +</table> + +<hr> +<div class="header"> +<p> +Next: <a href="Header-Files.html#Header-Files" accesskey="n" rel="next">Header Files</a>, Previous: <a href="index.html#Top" accesskey="p" rel="previous">Top</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> |