spl-object-hash.xml

<?xml version="1.0" encoding="utf-8"?>
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<refentry xml:id="function.spl-object-hash" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>spl_object_hash</refname>
  <refpurpose>
   Return hash id for given object
  </refpurpose>
 </refnamediv>
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>string</type><methodname>spl_object_hash</methodname>
   <methodparam><type>object</type><parameter>object</parameter></methodparam>
  </methodsynopsis>
  <para>
   This function returns a unique identifier for the object. This id can be
   used as a hash key for storing objects, or for identifying an object, as long
   as the object is not destroyed. Once the object is destroyed, its hash may 
   be reused for other objects. This behavior is similar to
   <function>spl_object_id</function>.
  </para>
 </refsect1>

 <refsect1 role="parameters">
   &reftitle.parameters;
   <para>
    <variablelist>
     <varlistentry>
      <term><parameter>object</parameter></term>
      <listitem>
       <para>
        Any object. 
       </para>
      </listitem>
     </varlistentry>
    </variablelist>
   </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   A string that is unique for each currently existing object and is always
   the same for each object.
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title>A <function>spl_object_hash</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
$id = spl_object_hash($object);
$storage[$id] = $object;
?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>

 <refsect1 role="notes">
  &reftitle.notes;
  <note>
   <para>
    When an object is destroyed, its hash may be reused for other objects.
   </para>
  </note>
  <note>
   <para>
    Object hashes should be compared for identity with <code>===</code> and
    <code>!==</code>, because the returned hash could be a
    <link linkend="language.types.numeric-strings">numeric string</link>.
    For example: <literal>0000000000000e600000000000000000</literal>.
   </para>
  </note>
 </refsect1> 
 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>spl_object_id</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>
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