wp_get_post_categories() WordPress Function

function wp_get_post_categories( $post_id = 0, $args = array() ) {
	$post_id = (int) $post_id;

	$defaults = array( 'fields' => 'ids' );
	$args     = wp_parse_args( $args, $defaults );

	$cats = wp_get_object_terms( $post_id, 'category', $args );
	return $cats;
}
Uses	Description
wp-includes/functions.php:wp_parse_args()	Merges user defined arguments into defaults array.
wp-includes/taxonomy.php:wp_get_object_terms()	Retrieves the terms associated with the given object(s), in the supplied taxonomies.
Used By	Description
wp-admin/includes/post.php:bulk_edit_posts()	Processes the post data for the bulk editing of posts.
wp-includes/deprecated.php:wp_get_post_cats()	Retrieves a list of post categories.
wp-includes/class-wp-xmlrpc-server.php:wp_xmlrpc_server::mt_getPostCategories()	Retrieve post categories.
wp-includes/class-wp-xmlrpc-server.php:wp_xmlrpc_server::mt_publishPost()	Sets a post’s publish status to ‘publish’.
wp-includes/class-wp-xmlrpc-server.php:wp_xmlrpc_server::mw_getPost()	Retrieve post.
wp-includes/class-wp-xmlrpc-server.php:wp_xmlrpc_server::mw_getRecentPosts()	Retrieve list of recent posts.
wp-includes/class-wp-xmlrpc-server.php:wp_xmlrpc_server::blogger_getPost()	Retrieve post.
wp-includes/class-wp-xmlrpc-server.php:wp_xmlrpc_server::blogger_getRecentPosts()	Retrieve list of recent posts.
wp-includes/class-wp-xmlrpc-server.php:wp_xmlrpc_server::_prepare_page()	Prepares page data for return in an XML-RPC object.