< programming , operating system > 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 .
(1998-02-06)