umask Changes the current umask intumask intmask umask sets PHP's umask to mask & 0777 and returns the old umask. When PHP is being used as a server module, the umask is restored when each request is finished. umask without arguments simply returns the current umask. Avoid using this function in multithreaded webservers. Better change the file permissions with chmod after creating the file. Using umask can lead to unexspected behavior of concurrently running scripts and the webserver itsself because they all use the same umask.