(PHP 4 >= 4.2.0, PHP 5, PHP 7) Alias of

(PHP 4, PHP 5, PHP 7) Pathname of current directory

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

(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 UID of the current process

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