php-doc-en/reference/var/functions/is-resource.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<!-- splitted from ./en/functions/var.xml, last change in rev 1.19 -->
<refentry xml:id="function.is-resource" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>is_resource</refname>
  <refpurpose>
   Finds whether a variable is a resource
  </refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>bool</type><methodname>is_resource</methodname>
   <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
  </methodsynopsis>
  <para>
   Finds whether the given variable is a <type>resource</type>.
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>var</parameter></term>
     <listitem>
      <para>
       The variable being evaluated.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns &true; if <parameter>var</parameter> is a <type>resource</type>,
   &false; otherwise.
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>is_resource</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php

$db_link = @mysql_connect('localhost', 'mysql_user', 'mysql_pass');
if (!is_resource($db_link)) {
    die('Can\'t connect : ' . mysql_error());
}

?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>
 
 <refsect1 role="notes">
  &reftitle.notes;
  <note>
   <para>
    <function>is_resource</function> is not a strict type-checking method: it will return &false; if <parameter>var</parameter> is a resource variable that has been closed.
   </para>
  </note>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><link linkend="language.types.resource">The resource-type documentation</link></member>
    <member><function>get_resource_type</function></member>
   </simplelist>
  </para>  
 </refsect1>
</refentry>

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