FILE_STATUS_PERMANENT

in includes/file.inc

Indicates that the file is permanent and should not be deleted.

Temporary files older than DRUPAL_MAXIMUM_TEMP_FILE_AGE will be removed during cron runs, but permanent files will not be removed during the file garbage collection process.

<?php
define('FILE_STATUS_PERMANENT', 1);
?>

Related topics

File interface

Common file handling functions.