POSIX
PHP Manual

Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

POSIX_F_OK (integer)
Check whether the file exists.
POSIX_R_OK (integer)
Check whether the file exists and has read permissions.
POSIX_W_OK (integer)
Check whether the file exists and has write permissions.
POSIX_X_OK (integer)
Check whether the file exists and has execute permissions.
POSIX_S_IFBLK (integer)
Block special file
POSIX_S_IFCHR (integer)
Character special file
POSIX_S_IFIFO (integer)
FIFO (named pipe) special file
POSIX_S_IFREG (integer)
Normal file
POSIX_S_IFSOCK (integer)
Socket

Note:

These constants are available since PHP 5.1.0. Please also note that some of them may not be available in your system.


POSIX
PHP Manual