I'd like to find the time difference -preferably in hours- between post_date and post_date_gmt.
$age = date_diff(get_post_time(),get_post_time($gmt = true));
but this returns
Warning: date_diff() expects parameter 1 to be DateTimeInterface, int given in C:\xampp\htdocs\t\wp-content\themes\i\single.php on line 23
I didn't really understand the official WP documentation on this function -do they refer to just "time" or "timestamps"?
The basic reason is that I abused the post_date to store the last update date while the gmt field still contains the original publication date. I know that's wrong but I needed a quick and dirty solution some time ago for a different problem.