(PHP 5 >= 5.1.0, PHP 7) Create a special or ordinary file (POSIX.1)

(PHP 5 >= 5.2.0, PHP 7) Calculate the group access list

(PHP 4, PHP 5, PHP 7) Create a fifo special file (a named pipe)

(PHP 4, PHP 5, PHP 7) Get process group id for job control

(PHP 4, PHP 5, PHP 7) Return the real user ID of the current process

(PHP 4 >= 4.0.2, PHP 5, PHP 7) Set the effective GID of the current process

(PHP 4, PHP 5, PHP 7) Get path name of controlling terminal

(PHP 4, PHP 5, PHP 7) Set process group id for job control

(PHP 4 >= 4.2.0, PHP 5, PHP 7) Retrieve the error number set by the last posix function that failed

(PHP 4 >= 4.0.2, PHP 5, PHP 7) Set the effective UID of the current process