SQLite3::createFunction

Registers a PHP function for use as an SQL scalar function

&reftitle.description; public `bool` `SQLite3::createFunction` `string` `name` `callable` `callback` `int` `argCount`-1 `int` `flags` 0

Registers a PHP function or user-defined function for use as an SQL scalar function for use within SQL statements.

&reftitle.parameters;

`name`

- Name of the SQL function to be created or redefined.

`callback`

- The name of a PHP function or user-defined function to apply as a callback, defining the behavior of the SQL function.

  This function need to be defined as: `mixed```callback`` `mixed` `value` `mixed` `values`

  `value`

- The first argument passed to the SQL function.

`values`

- Further arguments passed to the SQL function.

`argCount`

- The number of arguments that the SQL function takes. If this parameter is `-1`, then the SQL function may take any number of arguments.

`flags`

- A bitwise conjunction of flags. Currently, only `SQLITE3_DETERMINISTIC` is supported, which specifies that the function always returns the same result given the same inputs within a single SQL statement.

&reftitle.returnvalues;

Returns &true; upon successful creation of the function, &false; on failure.

&reftitle.changelog;

&Version; | &Description;
7.1.4 | The `flags` parameter has been added.

&reftitle.examples;

### `SQLite3::createFunction` example

    <?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")'));
    ?>

&example.outputs.similar;

    string(32) "098f6bcd4621d373cade4e832627b4f6"