A
variable which represents an
file to which a
program has
access. In
Unix-related systems and
languages, most processes start out with a few
standard filehandles for user
I/O, and get more by
opening files.
In Unix, filehandles are implemented as "file descriptors", which are simply ints issued serially to a process by the kernel. In application C code, you're more likely to use FILE pointers (i.e. streams) as filehandles; these are a somewhat more stateful and easy-to-use wrapper around Unix file descriptors. C++'s iostream objects and Perl's filehandles are yet higher-level kinds of filehandle.