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diff --git a/share/doc/cpp/Misnesting.html b/share/doc/cpp/Misnesting.html new file mode 100644 index 0000000..4a47bb9 --- /dev/null +++ b/share/doc/cpp/Misnesting.html @@ -0,0 +1,115 @@ +<!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: Misnesting</title> + +<meta name="description" content="The C Preprocessor: Misnesting"> +<meta name="keywords" content="The C Preprocessor: Misnesting"> +<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="Macro-Pitfalls.html#Macro-Pitfalls" rel="up" title="Macro Pitfalls"> +<link href="Operator-Precedence-Problems.html#Operator-Precedence-Problems" rel="next" title="Operator Precedence Problems"> +<link href="Macro-Pitfalls.html#Macro-Pitfalls" rel="previous" title="Macro Pitfalls"> +<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="Misnesting"></a> +<div class="header"> +<p> +Next: <a href="Operator-Precedence-Problems.html#Operator-Precedence-Problems" accesskey="n" rel="next">Operator Precedence Problems</a>, Up: <a href="Macro-Pitfalls.html#Macro-Pitfalls" accesskey="u" rel="up">Macro Pitfalls</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="Misnesting-1"></a> +<h4 class="subsection">3.10.1 Misnesting</h4> + +<p>When a macro is called with arguments, the arguments are substituted +into the macro body and the result is checked, together with the rest of +the input file, for more macro calls. It is possible to piece together +a macro call coming partially from the macro body and partially from the +arguments. For example, +</p> +<div class="smallexample"> +<pre class="smallexample">#define twice(x) (2*(x)) +#define call_with_1(x) x(1) +call_with_1 (twice) + → twice(1) + → (2*(1)) +</pre></div> + +<p>Macro definitions do not have to have balanced parentheses. By writing +an unbalanced open parenthesis in a macro body, it is possible to create +a macro call that begins inside the macro body but ends outside of it. +For example, +</p> +<div class="smallexample"> +<pre class="smallexample">#define strange(file) fprintf (file, "%s %d", +… +strange(stderr) p, 35) + → fprintf (stderr, "%s %d", p, 35) +</pre></div> + +<p>The ability to piece together a macro call can be useful, but the use of +unbalanced open parentheses in a macro body is just confusing, and +should be avoided. +</p> + + + +</body> +</html> |