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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 $
36 .\" $DragonFly: src/share/man/man5/fdesc.5,v 1.2 2003/06/17 04:37:00 dillon Exp $
43 .Nd file-descriptor file system
45 fdesc /dev fdesc rw 0 0
47 The file-descriptor file system, or
49 provides access to the per-process file descriptor
50 namespace in the global filesystem namespace.
51 The conventional mount point is
53 and the filesystem should be union mounted in order to augment,
54 rather than replace, the existing entries in
57 The contents of the mount point are
66 is a directory whose contents
67 appear as a list of numbered files
68 which correspond to the open files of the process reading the
74 refer to file descriptors which can be accessed through the file
76 If the file descriptor is open and the mode the file is being opened
77 with is a subset of the mode of the existing descriptor, the call:
78 .Bd -literal -offset indent
79 fd = open("/dev/fd/0", mode);
83 .Bd -literal -offset indent
84 fd = fcntl(0, F_DUPFD, 0);
94 appear as symlinks to the relevant entry in the
97 Opening them is equivalent to the following calls:
98 .Bd -literal -offset indent
99 fd = fcntl(STDIN_FILENO, F_DUPFD, 0);
100 fd = fcntl(STDOUT_FILENO, F_DUPFD, 0);
101 fd = fcntl(STDERR_FILENO, F_DUPFD, 0);
115 entry is an indirect reference to the current process's controlling terminal.
116 It appears as a named pipe (FIFO) but behaves in exactly the same way as
117 the real controlling terminal device.
119 .Bl -tag -width /dev/stderr -compact
132 filesystem first appeared in
136 manual page first appeared in
142 manual page was written by
143 .An Mike Pritchard Aq mpp@FreeBSD.org ,
146 manual page written by
147 .An Jan-Simon Pendry .