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39 .\" $FreeBSD: src/share/man/man5/fdesc.5,v 1.6.2.4 2001/12/20 16:50:57 ru Exp $
46 .Nd file-descriptor file system
48 fdesc /dev fdesc rw 0 0
50 The file-descriptor file system, or
52 provides access to the per-process file descriptor
53 namespace in the global filesystem namespace.
54 The conventional mount point is
56 and the filesystem should be union mounted in order to augment,
57 rather than replace, the existing entries in
60 The contents of the mount point are
69 is a directory whose contents
70 appear as a list of numbered files
71 which correspond to the open files of the process reading the
77 refer to file descriptors which can be accessed through the file
79 If the file descriptor is open and the mode the file is being opened
80 with is a subset of the mode of the existing descriptor, the call:
81 .Bd -literal -offset indent
82 fd = open("/dev/fd/0", mode);
86 .Bd -literal -offset indent
87 fd = fcntl(0, F_DUPFD, 0);
97 appear as symlinks to the relevant entry in the
100 Opening them is equivalent to the following calls:
101 .Bd -literal -offset indent
102 fd = fcntl(STDIN_FILENO, F_DUPFD, 0);
103 fd = fcntl(STDOUT_FILENO, F_DUPFD, 0);
104 fd = fcntl(STDERR_FILENO, F_DUPFD, 0);
118 entry is an indirect reference to the current process's controlling terminal.
119 It appears as a named pipe (FIFO) but behaves in exactly the same way as
120 the real controlling terminal device.
122 .Bl -tag -width /dev/stderr -compact
135 filesystem first appeared in
139 manual page first appeared in
145 manual page was written by
146 .An Mike Pritchard Aq mpp@FreeBSD.org ,
149 manual page written by
150 .An Jan-Simon Pendry .