An integer that identifies an
open
file within a
process. This number is obtained as a
result of opening a file. Operations which read, write, or
close a file would take the file descriptor as an input
parameter.
In many
operating system implementations, file descriptors
are small integers which index a table of open files. In
Unix, file descriptors 0, 1 and 2 correspond to the
standard input,
standard output and
standard error files
respectively.
See
file descriptor leak.