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<title>List of Keywords</title>
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<h2 class="title">List of Keywords</h2>
<p class="simpara">
These words have special meaning in PHP. Some of them represent things
which look like functions, some look like constants, and so on - but
they're not, really: they are language constructs. You cannot use any
of the following words as constants, class names, function or method names.
Using them as variable names is generally OK, but could lead to confusion.
</p>
<p class="simpara">
As of PHP 7.0.0 these keywords are allowed as property, constant, and
method names of classes, interfaces and traits, except that
<em>class</em> may not be used as constant name.
</p>
<table class="doctable table">
<caption><strong>PHP Keywords</strong></caption>
<tbody class="tbody">
<tr>
<td>
<span class="function"><a href="function.halt-compiler.html" class="function">__halt_compiler()</a></span>
</td>
<td>
<a href="language.oop5.abstract.html" class="link">abstract</a>
</td>
<td>
<a href="language.operators.logical.html" class="link">and</a>
</td>
<td>
<span class="function"><a href="function.array.html" class="function">array()</a></span>
</td>
<td>
<a href="control-structures.foreach.html" class="link">as</a>
</td>
</tr>
<tr>
<td>
<a href="control-structures.break.html" class="link">break</a>
</td>
<td>
<a href="language.types.callable.html" class="link">callable</a> (as of PHP 5.4)
</td>
<td>
<a href="control-structures.switch.html" class="link">case</a>
</td>
<td>
<a href="language.exceptions.html" class="link">catch</a>
</td>
<td>
<a href="language.oop5.basic.html#language.oop5.basic.class" class="link">class</a>
</td>
</tr>
<tr>
<td>
<a href="language.oop5.cloning.html" class="link">clone</a>
</td>
<td>
<a href="language.oop5.constants.html" class="link">const</a>
</td>
<td>
<a href="control-structures.continue.html" class="link">continue</a>
</td>
<td>
<a href="control-structures.declare.html" class="link">declare</a>
</td>
<td>
<a href="control-structures.switch.html" class="link">default</a>
</td>
</tr>
<tr>
<td>
<span class="function"><a href="function.die.html" class="function">die()</a></span>
</td>
<td>
<a href="control-structures.do.while.html" class="link">do</a>
</td>
<td>
<span class="function"><a href="function.echo.html" class="function">echo</a></span>
</td>
<td>
<a href="control-structures.else.html" class="link">else</a>
</td>
<td>
<a href="control-structures.elseif.html" class="link">elseif</a>
</td>
</tr>
<tr>
<td>
<span class="function"><a href="function.empty.html" class="function">empty()</a></span>
</td>
<td>
<a href="control-structures.declare.html" class="link">enddeclare</a>
</td>
<td>
<a href="control-structures.alternative-syntax.html" class="link">endfor</a>
</td>
<td>
<a href="control-structures.alternative-syntax.html" class="link">endforeach</a>
</td>
<td>
<a href="control-structures.alternative-syntax.html" class="link">endif</a>
</td>
</tr>
<tr>
<td>
<a href="control-structures.alternative-syntax.html" class="link">endswitch</a>
</td>
<td>
<a href="control-structures.alternative-syntax.html" class="link">endwhile</a>
</td>
<td>
<span class="function"><a href="function.eval.html" class="function">eval()</a></span>
</td>
<td>
<span class="function"><a href="function.exit.html" class="function">exit()</a></span>
</td>
<td>
<a href="language.oop5.basic.html#language.oop5.basic.extends" class="link">extends</a>
</td>
</tr>
<tr>
<td>
<a href="language.oop5.final.html" class="link">final</a>
</td>
<td>
<a href="language.exceptions.html" class="link">finally</a> (as of PHP 5.5)
</td>
<td>
<a href="control-structures.for.html" class="link">for</a>
</td>
<td>
<a href="control-structures.foreach.html" class="link">foreach</a>
</td>
<td>
<a href="functions.user-defined.html" class="link">function</a>
</td>
</tr>
<tr>
<td>
<a href="language.variables.scope.html" class="link">global</a>
</td>
<td>
<a href="control-structures.goto.html" class="link">goto</a> (as of PHP 5.3)
</td>
<td>
<a href="control-structures.if.html" class="link">if</a>
</td>
<td>
<a href="language.oop5.interfaces.html" class="link">implements</a>
</td>
<td>
<span class="function"><a href="function.include.html" class="function">include</a></span>
</td>
</tr>
<tr>
<td>
<span class="function"><a href="function.include-once.html" class="function">include_once</a></span>
</td>
<td>
<a href="language.operators.type.html" class="link">instanceof</a>
</td>
<td>
<a href="language.oop5.traits.html#language.oop5.traits.conflict" class="link">insteadof</a> (as of PHP 5.4)
</td>
<td>
<a href="language.oop5.interfaces.html" class="link">interface</a>
</td>
<td>
<span class="function"><a href="function.isset.html" class="function">isset()</a></span>
</td>
</tr>
<tr>
<td>
<span class="function"><a href="function.list.html" class="function">list()</a></span>
</td>
<td>
<a href="language.namespaces.html" class="link">namespace</a> (as of PHP 5.3)
</td>
<td>
<a href="language.oop5.basic.html#language.oop5.basic.new" class="link">new</a>
</td>
<td>
<a href="language.operators.logical.html" class="link">or</a>
</td>
<td>
<span class="function"><a href="function.print.html" class="function">print</a></span>
</td>
</tr>
<tr>
<td>
<a href="language.oop5.visibility.html" class="link">private</a>
</td>
<td>
<a href="language.oop5.visibility.html" class="link">protected</a>
</td>
<td>
<a href="language.oop5.visibility.html" class="link">public</a>
</td>
<td>
<span class="function"><a href="function.require.html" class="function">require</a></span>
</td>
<td>
<span class="function"><a href="function.require-once.html" class="function">require_once</a></span>
</td>
</tr>
<tr>
<td>
<span class="function"><a href="function.return.html" class="function">return</a></span>
</td>
<td>
<a href="language.variables.scope.html" class="link">static</a>
</td>
<td>
<a href="control-structures.switch.html" class="link">switch</a>
</td>
<td>
<a href="language.exceptions.html" class="link">throw</a>
</td>
<td>
<a href="language.oop5.traits.html" class="link">trait</a> (as of PHP 5.4)
</td>
</tr>
<tr>
<td>
<a href="language.exceptions.html" class="link">try</a>
</td>
<td>
<span class="function"><a href="function.unset.html" class="function">unset()</a></span>
</td>
<td>
<a href="language.namespaces.html" class="link">use</a>
</td>
<td>
<a href="language.oop5.properties.html" class="link">var</a>
</td>
<td>
<a href="control-structures.while.html" class="link">while</a>
</td>
</tr>
<tr>
<td>
<a href="language.operators.logical.html" class="link">xor</a>
</td>
<td>
<a href="language.generators.html" class="link">yield</a> (as of PHP 5.5)
</td>
<td>
</td>
<td>
</td>
<td>
</td>
</tr>
</tbody>
</table>
<table class="doctable table">
<caption><strong>Compile-time constants</strong></caption>
<tbody class="tbody">
<tr>
<td>
<a href="language.constants.predefined.html" class="link">__CLASS__</a>
</td>
<td>
<a href="language.constants.predefined.html" class="link">__DIR__</a> (as of PHP 5.3)
</td>
<td>
<a href="language.constants.predefined.html" class="link">__FILE__</a>
</td>
<td>
<a href="language.constants.predefined.html" class="link">__FUNCTION__</a>
</td>
<td>
<a href="language.constants.predefined.html" class="link">__LINE__</a>
</td>
<td>
<a href="language.constants.predefined.html" class="link">__METHOD__</a>
</td>
</tr>
<tr>
<td>
<a href="language.namespaces.nsconstants.html" class="link">__NAMESPACE__</a> (as of PHP 5.3)
</td>
<td>
<a href="language.constants.predefined.html" class="link">__TRAIT__</a> (as of PHP 5.4)
</td>
<td>
</td>
<td>
</td>
<td>
</td>
<td>
</td>
</tr>
</tbody>
</table>
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