handle. Handle objects are primarily used to
hide the underlying data or refer to data structures in object code - for
instance, process ID numbers and file descriptor numbers by
process
objects.
is.handle(x)
TRUE if
x is of class
handle (or derived from that class)
and
FALSE otherwise.
This function just checks to see if an object inherits from the class
handle
. It does not check to see if the
handle is valid or in use for
the current S-PLUS session.
if(is.handle(xx) && handle.valid(xx)) print("It's a valid handle")