I'm running a wordpress plugin and continue to receive errors like:

Undefined variable $admin in C:\xampp\htdocs\wordpress\apps\wordpress\htdocs\wp-content\plugins\wordpress-database\vragen_plugin.php on line 791

This was my code:

    // If ur an admin, you have access to the following page
    if($admin == '1'){
// When going to /Stel-vraag?createquestion=...
        if (isset($_POST['createquestion'])) {
            $short_question = filter_input(INPUT_POST, 'short_question', FILTER_SANITIZE_SPECIAL_CHARS);
            $long_question = filter_input(INPUT_POST, 'long_question', FILTER_SANITIZE_SPECIAL_CHARS);
            if (!isset($_POST['comment'])) { $comment = 'Nee';} else { $comment = filter_input(INPUT_POST, 'comment', FILTER_SANITIZE_SPECIAL_CHARS); }
            $uniq_name = substr(md5(uniqid(rand())),0,10);
  • 3
    So where did you define $admin? It's not defined, so the error happens. Perhaps you meant to use is_admin() ? Commented Dec 1, 2022 at 1:45

1 Answer 1


The error is telling that when you say:

if($admin == '1'){

PHP has no idea what you are talking about. There is no $admin so it cannot ever equal 1.

As Rick Hellewell mentioned in the comments, you might actually want is_admin() which is a function that returns a boolean (true or false).

It is quite likely the code you actually want would be like this:

// If ur an admin, you have access to the following page
if( is_user_admin() ){
// When going ...[snip]...

Edit: I originally suggested is_admin() which I was reminded checks the page is loaded in the admin area. I should have said is_user_admin()

  • Please be aware that is_admin DOESN'T return if the user is an admin or not, but instead returns true if you are viewing a page within the "admin" (Backend) section of Wordpress at the moment this function is run... Commented Dec 2, 2022 at 12:20
  • Ah, yeah. You are right. HU is Sebastian. I shall update my answer. Commented Dec 4, 2022 at 8:19
  • This is still not what you want ;) is_user_admin returns true if you are viewing the user admin screen in the backend, i.e. /wp-admin/user/ . If you want to know if the current user is in the admin role, you should use current_user_can('administrator') if you want to target the administrator role specifically, or current_user_can('manage_options') if you want to target users that have administrative rights... Commented Dec 5, 2022 at 7:16

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