How to create a library?

Example CI 4 Library

PHP Code:

<?php namespace App\Libraries;

/**
 * Class ExampleLibrary
 *
 * @package App\Libraries
 */
class ExampleLibrary
{
    /**
     * Class properties go here.
     * -------------------------------------------------------------------
     * public, private, protected, static and const.
     */


    // -------------------------------------------------------------------

    /**
     * __construct ()
     * -------------------------------------------------------------------
     *
     * Class    Constructor
     *
     * NOTE: Not needed if not setting values or extending a Class.
     *
     */
    public function __construct()
    {

    }

    // -------------------------------------------------------------------

}   // End of Name Library Class.

/**
 * -----------------------------------------------------------------------
 * Filename: ExampleLibrary.php
 * Location: ./app/Libraries/ExampleLibrary.php
 * -----------------------------------------------------------------------
 */ 


Example Controller loading the Example Library:

PHP Code:

<?php namespace App\Controllers;

use App\Libraries\ExampleLibrary;

/**
 * Class ExampleController
 *
 * @package App\Controllers
 */
class ExampleController extends BaseController
{
    /**
     * Class properties go here.
     * -------------------------------------------------------------------
     * public, private, protected, static and const.
     */


    // -------------------------------------------------------------------

    /**
     * __construct ()
     * -------------------------------------------------------------------
     *
     * Class    Constructor
     *
     * NOTE: Not needed if not setting values or extending a Class.
     *
     */
    public function __construct()
    {
        parent::__construct();

    }

    // -------------------------------------------------------------------

    /**
     * index ()
     * -------------------------------------------------------------------
     *
     */
    public function index()
    {
        $newExampleLibrary = new ExampleLibrary();
    }
    
    // --------------------------------------------------------------------

}   // End of ExampleController Controller Class.

/**
 * -----------------------------------------------------------------------
 * Filename: ExampleController.php
 * Location: ./app/Controllers/ExampleController.php
 * -----------------------------------------------------------------------
 */ 


Try that.

Thanks!