Receive notification when change occur within the fd.
To use, create a Stdio.File object of a directory like
Stdio.File(".") and then call notify() with the appropriate
parameters.
Note
When a program registers for some notification, only the first notification
will be received unless DN_MULTISHOT is specified as part of the
notification argument.
Note
At present, this function is Linux-specific and requires a kernel which
supports the F_NOTIFY fcntl() call.
Parameter notification
What to notify the callback of. See the Stdio.DN_* constants for more
information about possible notifications.
Parameter callback
Function which should be called when notification is received. The
function gets the signal used to indicate the notification as its
argument and shouldn't return anyting.
Module reference for Pike v7.8 release 116, 2008-12-31