Codeigniter - Call to undefined function set_value()
You must load library('form_validation') in your Controller.This work for me:
<?phpdefined('BASEPATH') OR exit('No direct script access allowed');class Login extends CI_Controller{ public function __construct(){ parent::__construct(); $this -> load -> library('form_validation'); }....
In CodeIgniter4 you have only to use the helper function to load the library
<?php namespace App\Controllers;use App\Models\UserModel;class Users extends BaseController {public function index(){ helper (['form']); ......