sigmasternchen/php-doc-en
1
0
Fork 0
mirror of https://github.com/sigmasternchen/php-doc-en synced 2025-03-16 08:58:56 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Added simple example

Browse source 
Cleaned initial example
Added links to autoload


git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@169150 c90b9560-bf6c-de11-be94-00142212c4b1
This commit is contained in:
Aidan Lister 2004-09-25 09:06:35 +00:00
parent 30f7de760e
commit 7276e35197
1 changed files with 43 additions and 25 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

68
reference/classobj/functions/class-exists.xml
View file

@ -1,5 +1,5 @@
<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision: 1.5 $ -->
<!-- $Revision: 1.6 $ -->
<!-- splitted from ./en/functions/classobj.xml, last change in rev 1.11 -->
<refentry id="function.class-exists">
<refnamediv>
@ -8,26 +8,37 @@
</refnamediv>
<refsect1>
<title>Description</title>
<methodsynopsis>
<type>bool</type><methodname>class_exists</methodname>
<methodparam><type>string</type><parameter>class_name</parameter></methodparam>
<methodparam choice="opt"><type>bool</type><parameter>autoload</parameter></methodparam>
</methodsynopsis>
<note>
<para>
The <parameter>autoload</parameter> parameter was added in PHP 5
</para>
</note>
<methodsynopsis>
<type>bool</type><methodname>class_exists</methodname>
<methodparam><type>string</type><parameter>class_name</parameter></methodparam>
<methodparam choice="opt"><type>bool</type><parameter>autoload</parameter></methodparam>
</methodsynopsis>
<para>
This function returns &true; if the class given by
<parameter>class_name</parameter> has been defined,
&false; otherwise.
</para>
<para>
<function>class_exists</function> will attempt to call __autoload by
default, if you don't want <function>class_exists</function> to
call __autoload(), you can set the parameter <parameter>autoload</parameter>
to &false;.
<example>
<title><function>class_exists</function> example</title>
<programlisting role="php">
<![CDATA[
<?php
// Check the class exists before trying to use it
if (class_exists('MyClass')) {
$myclass = new MyClass();
}
?>
]]>
</programlisting>
</example>
</para>
<para>
<function>class_exists</function> will attempt to call &link.autoload; by
default, if you don't want <function>class_exists</function> to
call &link.autoload;, you can set the parameter <parameter>autoload</parameter>
to &false;.
</para>
<para>
<example>
@ -35,26 +46,33 @@
<programlisting role="php">
<![CDATA[
<?php
function __autoload($class) {
include($class . '.php');
function __autoload($class)
{
include($class . '.php');
/* Check to see it the include defined the class */
if ( !class_exists($class, false) ) {
trigger_error("Unable to load class $class", E_USER_ERROR);
}
// Check to see if the include declared the class
if (!class_exists($class, false)) {
trigger_error("Unable to load class: $class", E_USER_WARNING);
}
}
if( class_exists('MyClass') ) {
$myclass = new MyClass();
}
if (class_exists('MyClass')) {
$myclass = new MyClass();
}
?>
]]>
</programlisting>
</example>
</para>
<note>
<para>
The <parameter>autoload</parameter> parameter was added in PHP 5
</para>
</note>
<simpara>
See also <function>get_declared_classes</function>.
See also <function>interface_exists</function>, and
<function>get_declared_classes</function>.
</simpara>
</refsect1>
</refentry>