Fatal Error in wp_get_current_user() Function

Question

When I use below in php code, I have a fatal error. What's happen? Let me know any reason.

$current_user = wp_get_current_user();
Fatal error: Call to undefined function is_user_logged_in() in

Answer 1

You call this function too early, before pluggable function is_user_logged_in() is defined. Try this:

function wpse_get_current_user() {
  $current_user = wp_get_current_user();
  // do other stuff here
}
add_action( 'init', 'wpse_get_current_user', 10 );