fdescfs(5)
NAME
fdescfs - file-descriptor file system
SYNOPSIS
fdescfs /dev/fd fdescfs rw 0 0
DESCRIPTION
- The file-descriptor file system, or fdescfs, provides access
- to the perprocess file descriptor namespace in the global file system
- namespace.
The conventional mount point is /dev/fd. - The file system's contents appear as a list of numbered
- files which correspond to the open files of the process reading the direc
- tory. The
files /dev/fd/0 through /dev/fd/# refer to file descriptors - which can be
accessed through the file system. If the file descriptor is - open and the
mode the file is being opened with is a subset of the mode - of the existing descriptor, the call:
fd = open("/dev/fd/0", mode);- and the call:
fd = fcntl(0, F_DUPFD, 0);- are equivalent.
- Flags to the open(2) call other than O_RDONLY, O_WRONLY and
- O_RDWR are
ignored.
FILES
/dev/fd/#
SEE ALSO
mount_devfs(8), mount_fdescfs(8)
HISTORY
- The fdescfs file system first appeared in 4.4BSD. The
- fdescfs manual
page first appeared in FreeBSD 2.2.
AUTHORS
- The fdescfs manual page was written by Mike Pritchard
- <mpp@FreeBSD.org>,
and was based on the mount_fdescfs(8) manual page written by - Jan-Simon
Pendry. - BSD December 14, 1996