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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 $
40 .\" $DragonFly: src/share/man/man5/fdesc.5,v 1.2 2003/06/17 04:37:00 dillon Exp $
47 .Nd file-descriptor file system
49 fdesc /dev fdesc rw 0 0
51 The file-descriptor file system, or
53 provides access to the per-process file descriptor
54 namespace in the global filesystem namespace.
55 The conventional mount point is
57 and the filesystem should be union mounted in order to augment,
58 rather than replace, the existing entries in
61 The contents of the mount point are
70 is a directory whose contents
71 appear as a list of numbered files
72 which correspond to the open files of the process reading the
78 refer to file descriptors which can be accessed through the file
80 If the file descriptor is open and the mode the file is being opened
81 with is a subset of the mode of the existing descriptor, the call:
82 .Bd -literal -offset indent
83 fd = open("/dev/fd/0", mode);
87 .Bd -literal -offset indent
88 fd = fcntl(0, F_DUPFD, 0);
98 appear as symlinks to the relevant entry in the
101 Opening them is equivalent to the following calls:
102 .Bd -literal -offset indent
103 fd = fcntl(STDIN_FILENO, F_DUPFD, 0);
104 fd = fcntl(STDOUT_FILENO, F_DUPFD, 0);
105 fd = fcntl(STDERR_FILENO, F_DUPFD, 0);
119 entry is an indirect reference to the current process's controlling terminal.
120 It appears as a named pipe (FIFO) but behaves in exactly the same way as
121 the real controlling terminal device.
123 .Bl -tag -width /dev/stderr -compact
136 filesystem first appeared in
140 manual page first appeared in
146 manual page was written by
147 .An Mike Pritchard Aq mpp@FreeBSD.org ,
150 manual page written by
151 .An Jan-Simon Pendry .