1<html lang="en"> 2<head> 3<title>Identifiers implementation - Using the GNU Compiler Collection (GCC)</title> 4<meta http-equiv="Content-Type" content="text/html"> 5<meta name="description" content="Using the GNU Compiler Collection (GCC)"> 6<meta name="generator" content="makeinfo 4.13"> 7<link title="Top" rel="start" href="index.html#Top"> 8<link rel="up" href="C-Implementation.html#C-Implementation" title="C Implementation"> 9<link rel="prev" href="Environment-implementation.html#Environment-implementation" title="Environment implementation"> 10<link rel="next" href="Characters-implementation.html#Characters-implementation" title="Characters implementation"> 11<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> 12<!-- 13Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 141998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 152010 Free Software Foundation, Inc. 16 17Permission is granted to copy, distribute and/or modify this document 18under the terms of the GNU Free Documentation License, Version 1.3 or 19any later version published by the Free Software Foundation; with the 20Invariant Sections being ``Funding Free Software'', the Front-Cover 21Texts being (a) (see below), and with the Back-Cover Texts being (b) 22(see below). A copy of the license is included in the section entitled 23``GNU Free Documentation License''. 24 25(a) The FSF's Front-Cover Text is: 26 27 A GNU Manual 28 29(b) The FSF's Back-Cover Text is: 30 31 You have freedom to copy and modify this GNU Manual, like GNU 32 software. Copies published by the Free Software Foundation raise 33 funds for GNU development.--> 34<meta http-equiv="Content-Style-Type" content="text/css"> 35<style type="text/css"><!-- 36 pre.display { font-family:inherit } 37 pre.format { font-family:inherit } 38 pre.smalldisplay { font-family:inherit; font-size:smaller } 39 pre.smallformat { font-family:inherit; font-size:smaller } 40 pre.smallexample { font-size:smaller } 41 pre.smalllisp { font-size:smaller } 42 span.sc { font-variant:small-caps } 43 span.roman { font-family:serif; font-weight:normal; } 44 span.sansserif { font-family:sans-serif; font-weight:normal; } 45--></style> 46<link rel="stylesheet" type="text/css" href="../cs.css"> 47</head> 48<body> 49<div class="node"> 50<a name="Identifiers-implementation"></a> 51<p> 52Next: <a rel="next" accesskey="n" href="Characters-implementation.html#Characters-implementation">Characters implementation</a>, 53Previous: <a rel="previous" accesskey="p" href="Environment-implementation.html#Environment-implementation">Environment implementation</a>, 54Up: <a rel="up" accesskey="u" href="C-Implementation.html#C-Implementation">C Implementation</a> 55<hr> 56</div> 57 58<h3 class="section">4.3 Identifiers</h3> 59 60 <ul> 61<li><cite>Which additional multibyte characters may appear in identifiers 62and their correspondence to universal character names (C99 6.4.2).</cite> 63 64 <p>See <a href="../cpp/Implementation_002ddefined-behavior.html#Implementation_002ddefined-behavior">Implementation-defined behavior</a>. 65 66 <li><cite>The number of significant initial characters in an identifier 67(C90 6.1.2, C90 and C99 5.2.4.1, C99 6.4.2).</cite> 68 69 <p>For internal names, all characters are significant. For external names, 70the number of significant characters are defined by the linker; for 71almost all targets, all characters are significant. 72 73 <li><cite>Whether case distinctions are significant in an identifier with 74external linkage (C90 6.1.2).</cite> 75 76 <p>This is a property of the linker. C99 requires that case distinctions 77are always significant in identifiers with external linkage and 78systems without this property are not supported by GCC. 79 80</ul> 81 82 </body></html> 83 84