mysql-ping.xml

<?xml version="1.0" encoding="utf-8"?>
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<refentry xmlns="http://docbook.org/ns/docbook" xml:id="function.mysql-ping">
 <refnamediv>
  <refname>mysql_ping</refname>
  <refpurpose>Ping a server connection or reconnect if there is no connection</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
  <warning>
   &mysql.alternative.note;
   <simplelist role="alternatives">
    <member><function>mysqli_ping</function></member>
   </simplelist>
  </warning>
 </refsynopsisdiv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>bool</type><methodname>mysql_ping</methodname>
   <methodparam choice="opt"><type>resource</type><parameter>link_identifier</parameter><initializer>NULL</initializer></methodparam>
  </methodsynopsis>
  <simpara>
   Checks whether or not the connection to
   the server is working. If it has gone down, an automatic reconnection is
   attempted. This function can be used by scripts that remain idle for a
   long while, to check whether or not the server has closed the connection
   and reconnect if necessary.
  </simpara>
  <note>
   <simpara>
    Automatic reconnection is disabled by default in versions of MySQL &gt;= 5.0.3.
   </simpara>
  </note>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <variablelist>
   &mysql.linkid.description;
  </variablelist>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <simpara>
   Returns &true; if the connection to the server MySQL server is working,
   otherwise &false;.
  </simpara>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <example>
   <title>A <function>mysql_ping</function> example</title>
   <programlisting role="php">
<![CDATA[
<?php
set_time_limit(0);

$conn = mysql_connect('localhost', 'mysqluser', 'mypass');
$db   = mysql_select_db('mydb');

/* Assuming this query will take a long time */
$result = mysql_query($sql);
if (!$result) {
    echo 'Query #1 failed, exiting.';
    exit;
}

/* Make sure the connection is still alive, if not, try to reconnect */
if (!mysql_ping($conn)) {
    echo 'Lost connection, exiting after query #1';
    exit;
}
mysql_free_result($result);

/* So the connection is still alive, let's run another query */
$result2 = mysql_query($sql2);
?>
]]>
   </programlisting>
  </example>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <simplelist>
   <member><function>mysql_thread_id</function></member>
   <member><function>mysql_list_processes</function></member>
  </simplelist>
 </refsect1>
</refentry>
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