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+<p>
+Next: <a href="Type-encoding.html#Type-encoding" accesskey="n" rel="next">Type encoding</a>, Previous: <a href="GNU-Objective_002dC-runtime-API.html#GNU-Objective_002dC-runtime-API" accesskey="p" rel="previous">GNU Objective-C runtime API</a>, Up: <a href="Objective_002dC.html#Objective_002dC" accesskey="u" rel="up">Objective-C</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Indices.html#Indices" title="Index" rel="index">Index</a>]</p>
+</div>
+<hr>
+<a name="g_t_002bload_003a-Executing-Code-before-main"></a>
+<h3 class="section">8.2 <code>+load</code>: Executing Code before <code>main</code></h3>
+
+<p>This section is specific for the GNU Objective-C runtime.  If you are
+using a different runtime, you can skip it.
+</p>
+<p>The GNU Objective-C runtime provides a way that allows you to execute
+code before the execution of the program enters the <code>main</code>
+function.  The code is executed on a per-class and a per-category basis,
+through a special class method <code>+load</code>.
+</p>
+<p>This facility is very useful if you want to initialize global variables
+which can be accessed by the program directly, without sending a message
+to the class first.  The usual way to initialize global variables, in the
+<code>+initialize</code> method, might not be useful because
+<code>+initialize</code> is only called when the first message is sent to a
+class object, which in some cases could be too late.
+</p>
+<p>Suppose for example you have a <code>FileStream</code> class that declares
+<code>Stdin</code>, <code>Stdout</code> and <code>Stderr</code> as global variables, like
+below:
+</p>
+<div class="smallexample">
+<pre class="smallexample">
+FileStream *Stdin = nil;
+FileStream *Stdout = nil;
+FileStream *Stderr = nil;
+
+@implementation FileStream
+
++ (void)initialize
+{
+    Stdin = [[FileStream new] initWithFd:0];
+    Stdout = [[FileStream new] initWithFd:1];
+    Stderr = [[FileStream new] initWithFd:2];
+}
+
+/* <span class="roman">Other methods here</span> */
+@end
+
+</pre></div>
+
+<p>In this example, the initialization of <code>Stdin</code>, <code>Stdout</code> and
+<code>Stderr</code> in <code>+initialize</code> occurs too late.  The programmer can
+send a message to one of these objects before the variables are actually
+initialized, thus sending messages to the <code>nil</code> object.  The
+<code>+initialize</code> method which actually initializes the global
+variables is not invoked until the first message is sent to the class
+object.  The solution would require these variables to be initialized
+just before entering <code>main</code>.
+</p>
+<p>The correct solution of the above problem is to use the <code>+load</code>
+method instead of <code>+initialize</code>:
+</p>
+<div class="smallexample">
+<pre class="smallexample">
+@implementation FileStream
+
++ (void)load
+{
+    Stdin = [[FileStream new] initWithFd:0];
+    Stdout = [[FileStream new] initWithFd:1];
+    Stderr = [[FileStream new] initWithFd:2];
+}
+
+/* <span class="roman">Other methods here</span> */
+@end
+
+</pre></div>
+
+<p>The <code>+load</code> is a method that is not overridden by categories.  If a
+class and a category of it both implement <code>+load</code>, both methods are
+invoked.  This allows some additional initializations to be performed in
+a category.
+</p>
+<p>This mechanism is not intended to be a replacement for <code>+initialize</code>.
+You should be aware of its limitations when you decide to use it
+instead of <code>+initialize</code>.
+</p>
+<table class="menu" border="0" cellspacing="0">
+<tr><td align="left" valign="top">&bull; <a href="What-you-can-and-what-you-cannot-do-in-_002bload.html#What-you-can-and-what-you-cannot-do-in-_002bload" accesskey="1">What you can and what you cannot do in +load</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
+</td></tr>
+</table>
+
+
+<hr>
+<div class="header">
+<p>
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