+++ /dev/null
-.\" Copyright (C) 2002 Andries Brouwer <aeb@cwi.nl>
-.\"
-.\" %%%LICENSE_START(VERBATIM)
-.\" Permission is granted to make and distribute verbatim copies of this
-.\" manual provided the copyright notice and this permission notice are
-.\" preserved on all copies.
-.\"
-.\" Permission is granted to copy and distribute modified versions of this
-.\" manual under the conditions for verbatim copying, provided that the
-.\" entire resulting derived work is distributed under the terms of a
-.\" permission notice identical to this one.
-.\"
-.\" Since the Linux kernel and libraries are constantly changing, this
-.\" manual page may be incorrect or out-of-date. The author(s) assume no
-.\" responsibility for errors or omissions, or for damages resulting from
-.\" the use of the information contained herein. The author(s) may not
-.\" have taken the same level of care in the production of this manual,
-.\" which is licensed free of charge, as they might when working
-.\" professionally.
-.\"
-.\" Formatted or processed versions of this manual, if unaccompanied by
-.\" the source, must acknowledge the copyright and authors of this work.
-.\" %%%LICENSE_END
-.\"
-.\" This replaces an earlier man page written by Walter Harms
-.\" <walter.harms@informatik.uni-oldenburg.de>.
-.\"
-.TH TTYSLOT 3 2013-07-22 "GNU" "Linux Programmer's Manual"
-.SH NAME
-ttyslot \- find the slot of the current user's terminal in some file
-.SH SYNOPSIS
-.BR "#include <unistd.h>" " /* on BSD-like systems, and Linux */"
-.br
-.BR "#include <stdlib.h>" " /* on System V-like systems */"
-.sp
-.B "int ttyslot(void);"
-.sp
-.in -4n
-Feature Test Macro Requirements for glibc (see
-.BR feature_test_macros (7)):
-.in
-.sp
-.ad l
-.BR ttyslot ():
-.RS 4
-_BSD_SOURCE ||
-.br
-_XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_\ <\ 500\ &&\ _XOPEN_SOURCE_EXTENDED
-.RE
-.ad b
-.SH DESCRIPTION
-The legacy function
-.BR ttyslot ()
-returns the index of the current user's entry in some file.
-.LP
-Now "What file?" you ask.
-Well, let's first look at some history.
-.SS Ancient history
-There used to be a file
-.I /etc/ttys
-in UNIX\ V6, that was read by the
-.BR init (1)
-program to find out what to do with each terminal line.
-Each line consisted of three characters.
-The first character was either \(aq0\(aq or \(aq1\(aq,
-where \(aq0\(aq meant "ignore".
-The second character denoted the terminal: \(aq8\(aq stood for "/dev/tty8".
-The third character was an argument to
-.BR getty (8)
-indicating the sequence of line speeds to try (\(aq\-\(aq was: start trying
-110 baud).
-Thus a typical line was "18\-".
-A hang on some line was solved by changing the \(aq1\(aq to a \(aq0\(aq,
-signaling init, changing back again, and signaling init again.
-.LP
-In UNIX\ V7 the format was changed: here the second character
-was the argument to
-.BR getty (8)
-indicating the sequence of line speeds to try (\(aq0\(aq was: cycle through
-300-1200-150-110 baud; \(aq4\(aq was for the on-line console DECwriter)
-while the rest of the line contained the name of the tty.
-Thus a typical line was "14console".
-.LP
-Later systems have more elaborate syntax.
-System V-like systems have
-.I /etc/inittab
-instead.
-.SS Ancient history (2)
-On the other hand, there is the file
-.I /etc/utmp
-listing the people currently logged in.
-It is maintained by
-.BR login (1).
-It has a fixed size, and the appropriate index in the file was
-determined by
-.BR login (1)
-using the
-.BR ttyslot ()
-call to find the number of the line in
-.I /etc/ttys
-(counting from 1).
-.SS The semantics of ttyslot
-Thus, the function
-.BR ttyslot ()
-returns the index of the controlling terminal of the calling process
-in the file
-.IR /etc/ttys ,
-and that is (usually) the same as the index of the entry for the
-current user in the file
-.IR /etc/utmp .
-BSD still has the
-.I /etc/ttys
-file, but System V-like systems do not, and hence cannot refer to it.
-Thus, on such systems the documentation says that
-.BR ttyslot ()
-returns the current user's index in the user accounting data base.
-.SH RETURN VALUE
-If successful, this function returns the slot number.
-On error (e.g., if none of the file descriptors 0, 1 or 2 is
-associated with a terminal that occurs in this data base)
-it returns 0 on UNIX\ V6 and V7 and BSD-like systems,
-but \-1 on System V-like systems.
-.SH ATTRIBUTES
-.SS Multithreading (see pthreads(7))
-The
-.BR ttyslot ()
-function calls thread-unsafe function
-.BR getttyent (),
-so it is not thread-safe.
-.SH CONFORMING TO
-SUSv1; marked as LEGACY in SUSv2; removed in POSIX.1-2001.
-SUSv2 requires \-1 on error.
-.SH NOTES
-The utmp file is found various places on various systems, such as
-.IR /etc/utmp ,
-.IR /var/adm/utmp ,
-.IR /var/run/utmp .
-.LP
-The glibc2 implementation of this function reads the file
-.BR _PATH_TTYS ,
-defined in
-.I <ttyent.h>
-as "/etc/ttys".
-It returns 0 on error.
-Since Linux systems do not usually have "/etc/ttys", it will
-always return 0.
-.LP
-Minix also has
-.IR fttyslot ( fd ).
-.\" .SH HISTORY
-.\" .BR ttyslot ()
-.\" appeared in UNIX V7.
-.SH SEE ALSO
-.BR getttyent (3),
-.BR ttyname (3),
-.BR utmp (5)
-.SH COLOPHON
-This page is part of release 3.79 of the Linux
-.I man-pages
-project.
-A description of the project,
-information about reporting bugs,
-and the latest version of this page,
-can be found at
-\%http://www.kernel.org/doc/man\-pages/.
OSDN Git Service
