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<refentry xml:id="sqlite3.createfunction" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
 <refnamediv>
  <refname>SQLite3::createFunction</refname>
  <refpurpose>Registers a PHP function for use as an SQL scalar function</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis role="SQLite3">
   <modifier>public</modifier> <type>bool</type><methodname>SQLite3::createFunction</methodname>
   <methodparam><type>string</type><parameter>name</parameter></methodparam>
   <methodparam><type>callable</type><parameter>callback</parameter></methodparam>
   <methodparam choice="opt"><type>int</type><parameter>argCount</parameter><initializer>-1</initializer></methodparam>
   <methodparam choice="opt"><type>int</type><parameter>flags</parameter><initializer>0</initializer></methodparam>
  </methodsynopsis>
  <para>
   Registers a PHP function or user-defined function for use as an SQL scalar
   function for use within SQL statements.
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>name</parameter></term>
     <listitem>
      <para>
       Name of the SQL function to be created or redefined.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>callback</parameter></term>
     <listitem>
      <para>
       The name of a PHP function or user-defined function to apply as a
       callback, defining the behavior of the SQL function.
      </para>
      <para>
       This function need to be defined as:
       <methodsynopsis>
        <type>mixed</type><methodname><replaceable>callback</replaceable></methodname>
        <methodparam><type>mixed</type><parameter>value</parameter></methodparam>
        <methodparam rep="repeat"><type>mixed</type><parameter>values</parameter></methodparam>
       </methodsynopsis>
       <variablelist>
        <varlistentry>
         <term><parameter>value</parameter></term>
         <listitem>
          <para>
           The first argument passed to the SQL function.
          </para>
         </listitem>
        </varlistentry>
        <varlistentry>
         <term><parameter>values</parameter></term>
         <listitem>
          <para>
           Further arguments passed to the SQL function.
          </para>
         </listitem>
        </varlistentry>
       </variablelist>
      </para> 
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>argCount</parameter></term>
     <listitem>
      <para>
       The number of arguments that the SQL function takes. If
       this parameter is <literal>-1</literal>, then the SQL function may take
       any number of arguments.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>flags</parameter></term>
     <listitem>
      <para>
       A bitwise conjunction of flags. Currently, only
       <constant>SQLITE3_DETERMINISTIC</constant> is supported, which specifies
       that the function always returns the same result given the same inputs
       within a single SQL statement.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>

 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns &true; upon successful creation of the function, &false; on failure.
  </para>
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <informaltable>
   <tgroup cols="2">
    <thead>
     <row>
      <entry>&Version;</entry>
      <entry>&Description;</entry>
     </row>
    </thead>
    <tbody>
     <row>
      <entry>7.1.4</entry>
      <entry>
       The <parameter>flags</parameter> parameter has been added.
      </entry>
     </row>
    </tbody>
   </tgroup>
  </informaltable>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>SQLite3::createFunction</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
function my_udf_md5($string) {
    return md5($string);
}

$db = new SQLite3('mysqlitedb.db');
$db->createFunction('my_udf_md5', 'my_udf_md5');

var_dump($db->querySingle('SELECT my_udf_md5("test")'));
?>
]]>
    </programlisting>
    &example.outputs.similar;
    <screen>
<![CDATA[
string(32) "098f6bcd4621d373cade4e832627b4f6"
]]>
    </screen>
   </example>
  </para>
 </refsect1>

</refentry>
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