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35 .\" $FreeBSD: src/share/man/man5/fdesc.5,v 1.6.2.4 2001/12/20 16:50:57 ru Exp $
42 .Nd file-descriptor file system
44 fdesc /dev fdesc rw 0 0
46 The file-descriptor file system, or
48 provides access to the per-process file descriptor
49 namespace in the global filesystem namespace.
50 The conventional mount point is
52 and the filesystem should be union mounted in order to augment,
53 rather than replace, the existing entries in
56 The contents of the mount point are
65 is a directory whose contents
66 appear as a list of numbered files
67 which correspond to the open files of the process reading the
73 refer to file descriptors which can be accessed through the file
75 If the file descriptor is open and the mode the file is being opened
76 with is a subset of the mode of the existing descriptor, the call:
77 .Bd -literal -offset indent
78 fd = open("/dev/fd/0", mode);
82 .Bd -literal -offset indent
83 fd = fcntl(0, F_DUPFD, 0);
93 appear as symlinks to the relevant entry in the
96 Opening them is equivalent to the following calls:
97 .Bd -literal -offset indent
98 fd = fcntl(STDIN_FILENO, F_DUPFD, 0);
99 fd = fcntl(STDOUT_FILENO, F_DUPFD, 0);
100 fd = fcntl(STDERR_FILENO, F_DUPFD, 0);
114 entry is an indirect reference to the current process's controlling terminal.
115 It appears as a named pipe (FIFO) but behaves in exactly the same way as
116 the real controlling terminal device.
118 .Bl -tag -width /dev/stderr -compact
131 filesystem first appeared in
135 manual page first appeared in
141 manual page was written by
142 .An Mike Pritchard Aq Mt mpp@FreeBSD.org ,
145 manual page written by
146 .An Jan-Simon Pendry .