1<html lang="en"> 2<head> 3<title>compatibility_alias - 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="Objective_002dC.html#Objective_002dC" title="Objective-C"> 9<link rel="prev" href="Constant-string-objects.html#Constant-string-objects" title="Constant string objects"> 10<link rel="next" href="Exceptions.html#Exceptions" title="Exceptions"> 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="compatibility_alias"></a> 51<a name="compatibility_005falias"></a> 52<p> 53Next: <a rel="next" accesskey="n" href="Exceptions.html#Exceptions">Exceptions</a>, 54Previous: <a rel="previous" accesskey="p" href="Constant-string-objects.html#Constant-string-objects">Constant string objects</a>, 55Up: <a rel="up" accesskey="u" href="Objective_002dC.html#Objective_002dC">Objective-C</a> 56<hr> 57</div> 58 59<h3 class="section">8.6 compatibility_alias</h3> 60 61<p>The keyword <code>@compatibility_alias</code> allows you to define a class name 62as equivalent to another class name. For example: 63 64<pre class="smallexample"> @compatibility_alias WOApplication GSWApplication; 65</pre> 66 <p>tells the compiler that each time it encounters <code>WOApplication</code> as 67a class name, it should replace it with <code>GSWApplication</code> (that is, 68<code>WOApplication</code> is just an alias for <code>GSWApplication</code>). 69 70 <p>There are some constraints on how this can be used— 71 72 <ul> 73<li><code>WOApplication</code> (the alias) must not be an existing class; 74 75 <li><code>GSWApplication</code> (the real class) must be an existing class. 76 77 </ul> 78 79<!-- ========================================================================= --> 80 </body></html> 81 82