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| author | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
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| committer | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
| commit | abdaadbcae30fe0c9a66c7516798279fdfd97750 (patch) | |
| tree | 00a54a6e25601e43876d03c1a4a12a749d4a914c /share/doc/cpp/Traditional-warnings.html | |
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diff --git a/share/doc/cpp/Traditional-warnings.html b/share/doc/cpp/Traditional-warnings.html new file mode 100644 index 0000000..591de60 --- /dev/null +++ b/share/doc/cpp/Traditional-warnings.html @@ -0,0 +1,131 @@ +<!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: Traditional warnings</title> + +<meta name="description" content="The C Preprocessor: Traditional warnings"> +<meta name="keywords" content="The C Preprocessor: Traditional warnings"> +<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="Traditional-Mode.html#Traditional-Mode" rel="up" title="Traditional Mode"> +<link href="Implementation-Details.html#Implementation-Details" rel="next" title="Implementation Details"> +<link href="Traditional-miscellany.html#Traditional-miscellany" rel="previous" title="Traditional miscellany"> +<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="Traditional-warnings"></a> +<div class="header"> +<p> +Previous: <a href="Traditional-miscellany.html#Traditional-miscellany" accesskey="p" rel="previous">Traditional miscellany</a>, Up: <a href="Traditional-Mode.html#Traditional-Mode" accesskey="u" rel="up">Traditional Mode</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="Traditional-warnings-1"></a> +<h3 class="section">10.4 Traditional warnings</h3> +<p>You can request warnings about features that did not exist, or worked +differently, in traditional C with the <samp>-Wtraditional</samp> option. +GCC does not warn about features of ISO C which you must use when you +are using a conforming compiler, such as the ‘<samp>#</samp>’ and ‘<samp>##</samp>’ +operators. +</p> +<p>Presently <samp>-Wtraditional</samp> warns about: +</p> +<ul> +<li> Macro parameters that appear within string literals in the macro body. +In traditional C macro replacement takes place within string literals, +but does not in ISO C. + +</li><li> In traditional C, some preprocessor directives did not exist. +Traditional preprocessors would only consider a line to be a directive +if the ‘<samp>#</samp>’ appeared in column 1 on the line. Therefore +<samp>-Wtraditional</samp> warns about directives that traditional C +understands but would ignore because the ‘<samp>#</samp>’ does not appear as the +first character on the line. It also suggests you hide directives like +‘<samp>#pragma</samp>’ not understood by traditional C by indenting them. Some +traditional implementations would not recognize ‘<samp>#elif</samp>’, so it +suggests avoiding it altogether. + +</li><li> A function-like macro that appears without an argument list. In some +traditional preprocessors this was an error. In ISO C it merely means +that the macro is not expanded. + +</li><li> The unary plus operator. This did not exist in traditional C. + +</li><li> The ‘<samp>U</samp>’ and ‘<samp>LL</samp>’ integer constant suffixes, which were not +available in traditional C. (Traditional C does support the ‘<samp>L</samp>’ +suffix for simple long integer constants.) You are not warned about +uses of these suffixes in macros defined in system headers. For +instance, <code>UINT_MAX</code> may well be defined as <code>4294967295U</code>, but +you will not be warned if you use <code>UINT_MAX</code>. + +<p>You can usually avoid the warning, and the related warning about +constants which are so large that they are unsigned, by writing the +integer constant in question in hexadecimal, with no U suffix. Take +care, though, because this gives the wrong result in exotic cases. +</p></li></ul> + +<hr> +<div class="header"> +<p> +Previous: <a href="Traditional-miscellany.html#Traditional-miscellany" accesskey="p" rel="previous">Traditional miscellany</a>, Up: <a href="Traditional-Mode.html#Traditional-Mode" accesskey="u" rel="up">Traditional Mode</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> |