file descriptor definition 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
See file descriptor leak