DUP(3)
NAME
dup − dups of open files
SYNOPSIS
bind #d /fd
/fd/0
/fd/1
...
DESCRIPTION
The dup device serves a one-level directory containing files whose names are decimal numbers. A file of name n corresponds to open file descriptor n in the current process.
An open(2) of file n results in a file descriptor identical to what would be returned from a system call dup(n, -1). Note that the result is no longer a file in the dup device.
The stat operation returns information about the device file, not the open file it points to. A stat of #d/n will contain n for the name, 0 for the length, and 0400, 0200, or 0600 for the mode, depending on whether the dup target is open for reading, writing, or both.
SEE ALSO
SOURCE
/sys/src/9/port/devdup.c
Plan 9 — April 04, 1995