WP_Query::__isset() │ public │ WP 4.0.0

Makes private properties checkable for backward compatibility.

Method of the class: WP_Query{}

No Hooks.

Return

true|false. Whether the property is set.

Usage

global $wp_query;
$wp_query->__isset( $name );
$name(string) (required)
Property to check if set.

Changelog

Since 4.0.0 Introduced.

WP_Query::__isset() code WP 6.7.1

wp-includes/class-wp-query.php 
public function __isset( $name ) {
	if ( in_array( $name, $this->compat_fields, true ) ) {
		return isset( $this->$name );
	}
}