I need the current post id in a function , which I have written in functions.php. But I can't get the id. I have tried several method.


get_the_ID(); //returns false 

global $post;
$id = $post->ID; //returns null  

global $wp_query
$id =$wp_query->get_queried_object_id(); //returns 0 

$url = 'http://'.$_SERVER["HTTP_HOST"] . $_SERVER["REQUEST_URI"];
$id = url_to_postid($url); //returns 0 

I am using the latest version of wordpress . What can I do now?

UPDATE: I need post id in the function below.

function em_change_form(){
    $id = get_the_ID();
    if(isset($_GET['reg_typ'])) {
        $reg_type = $_GET['reg_typ'];
        if($reg_type =='vln'){
            update_post_meta($id,'custom_booking_form', 2);
        } elseif ($reg_type == 'rsvp') {
            update_post_meta($id,'custom_booking_form', 1);

  • What is you function? Edit you question and post function code.
    – Robert hue
    Feb 6, 2015 at 6:07
  • if the function is: function example(){ global $post; return $id=$post->ID; } and is used in single.php, or page.php in general it should return the id of that post/page, and to see that in action you have echo it in there echo example(); Feb 6, 2015 at 6:10
  • @Roberthue I have edited my question Feb 6, 2015 at 6:18
  • @MayeenulIslam actually I do not need to pring anything , I just need to update meta value upon a form submit or when a specific link is clicked . Feb 6, 2015 at 6:20
  • 2
    The init hook is fired before the post id is set, so it will always return false, null or 0 Feb 6, 2015 at 6:25

1 Answer 1


The post ID is available after the query has been fired.

The first hook that is safe to get post id is 'template_redirect'.

If you can modify your function to accept a post id as argument, like so:

function em_change_form($id){
    $reg_type = filter_input(INPUT_GET, 'reg_typ', FILTER_SANITIZE_STRING);
    if($reg_type === 'vln'){
      update_post_meta($id,'custom_booking_form', 2);
    } elseif ($reg_type == 'rsvp') {
      update_post_meta($id,'custom_booking_form', 1);

You can do:

add_action('template_redirect', function() {
  if (is_single()){

I've used get_queried_object_id() to obtain current queried post id.

If you absolutely need to call your function on an early hook like 'init', you can use url_to_postid(), and home_url() + add_query_arg() to obtain current url:

add_action('init', function() {
  $url = home_url(add_query_arg(array()));
  $id = url_to_postid($url);
  if ($id) {

Note that second method is less performant because url_to_postid() forces WordPress to parse rewrite rules, so if you can, use the first method.

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