📄 what-you-can-and-what-you-cannot-do-in--load.html
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<html lang="en"><head><title>Using the GNU Compiler Collection (GCC)</title><meta http-equiv="Content-Type" content="text/html"><meta name="description" content="Using the GNU Compiler Collection (GCC)"><meta name="generator" content="makeinfo 4.6"><!--Copyright © 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc. <p>Permission is granted to copy, distribute and/or modify this documentunder the terms of the GNU Free Documentation License, Version 1.2 orany later version published by the Free Software Foundation; with theInvariant Sections being "GNU General Public License" and "FundingFree Software", the Front-Cover texts being (a) (see below), and withthe Back-Cover Texts being (b) (see below). A copy of the license isincluded in the section entitled "GNU Free Documentation License". <p>(a) The FSF's Front-Cover Text is: <p>A GNU Manual <p>(b) The FSF's Back-Cover Text is: <p>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.--><meta http-equiv="Content-Style-Type" content="text/css"><style type="text/css"><!-- pre.display { font-family:inherit } pre.format { font-family:inherit } pre.smalldisplay { font-family:inherit; font-size:smaller } pre.smallformat { font-family:inherit; font-size:smaller } pre.smallexample { font-size:smaller } pre.smalllisp { font-size:smaller }--></style></head><body><div class="node"><p>Node: <a name="What%20you%20can%20and%20what%20you%20cannot%20do%20in%20+load">What you can and what you cannot do in +load</a>,Previous: <a rel="previous" accesskey="p" href="Executing-code-before-main.html#Executing%20code%20before%20main">Executing code before main</a>,Up: <a rel="up" accesskey="u" href="Executing-code-before-main.html#Executing%20code%20before%20main">Executing code before main</a><hr><br></div><h3 class="subsection">What you can and what you cannot do in <code>+load</code></h4><p>The <code>+load</code> implementation in the GNU runtime guarantees you the followingthings: <ul> <li>you can write whatever C code you like; <li>you can send messages to Objective-C constant strings (<code>@"this is aconstant string"</code>); <li>you can allocate and send messages to objects whose class is implementedin the same file; <li>the <code>+load</code> implementation of all super classes of a class are executed before the <code>+load</code> of that class is executed; <li>the <code>+load</code> implementation of a class is executed before the<code>+load</code> implementation of any category. </ul> <p>In particular, the following things, even if they can work in aparticular case, are not guaranteed: <ul> <li>allocation of or sending messages to arbitrary objects; <li>allocation of or sending messages to objects whose classes have acategory implemented in the same file; </ul> <p>You should make no assumptions about receiving <code>+load</code> in siblingclasses when you write <code>+load</code> of a class. The order in whichsibling classes receive <code>+load</code> is not guaranteed. <p>The order in which <code>+load</code> and <code>+initialize</code> are called couldbe problematic if this matters. If you don't allocate objects inside<code>+load</code>, it is guaranteed that <code>+load</code> is called before<code>+initialize</code>. If you create an object inside <code>+load</code> the<code>+initialize</code> method of object's class is invoked even if<code>+load</code> was not invoked. Note if you explicitly call <code>+load</code>on a class, <code>+initialize</code> will be called first. To avoid possibleproblems try to implement only one of these methods. <p>The <code>+load</code> method is also invoked when a bundle is dynamicallyloaded into your running program. This happens automatically without anyintervening operation from you. When you write bundles and you need towrite <code>+load</code> you can safely create and send messages to objects whoseclasses already exist in the running program. The same restrictions asabove apply to classes defined in bundle. </body></html>⌨️ 快捷键说明
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