2004-11-03 13:51:07 +00:00
|
|
|
.\" Copyright (C) 2002 Andries Brouwer <aeb@cwi.nl>
|
|
|
|
.\"
|
|
|
|
.\" 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.
|
2007-04-12 22:42:49 +00:00
|
|
|
.\"
|
2004-11-03 13:51:07 +00:00
|
|
|
.\" 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.\" manual page may be incorrect or out-of-date.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.
|
2007-04-12 22:42:49 +00:00
|
|
|
.\"
|
2004-11-03 13:51:07 +00:00
|
|
|
.\" Formatted or processed versions of this manual, if unaccompanied by
|
|
|
|
.\" the source, must acknowledge the copyright and authors of this work.
|
|
|
|
.\"
|
|
|
|
.\" This replaces an earlier man page written by Walter Harms
|
|
|
|
.\" <walter.harms@informatik.uni-oldenburg.de>.
|
|
|
|
.\"
|
_exit.2, brk.2, capget.2, chdir.2, chmod.2, chown.2, chroot.2, getdtablesize.2, gethostname.2, getpagesize.2, getsid.2, killpg.2, mknod.2, mknodat.2, poll.2, posix_fadvise.2, pread.2, readlink.2, setpgid.2, setreuid.2, sigaltstack.2, stat.2, symlink.2, sync.2, truncate.2, vfork.2, wait.2, wait4.2, a64l.3, abs.3, acos.3, acosh.3, asin.3, asinh.3, atan.3, atan2.3, atoi.3, cbrt.3, ceil.3, copysign.3, cosh.3, dirfd.3, div.3, ecvt.3, erf.3, erfc.3, exp.3, exp2.3, fabs.3, fdim.3, ffs.3, floor.3, fma.3, fmax.3, fmin.3, fmod.3, fpclassify.3, frexp.3, ftw.3, fwide.3, gcvt.3, getcwd.3, getdate.3, getgrent.3, gethostid.3, getpass.3, getpwent.3, getsubopt.3, getw.3, hypot.3, ilogb.3, index.3, isalpha.3, isgreater.3, iswblank.3, j0.3, ldexp.3, lockf.3, log.3, log10.3, log1p.3, logb.3, lrint.3, lround.3, mkstemp.3, mktemp.3, modf.3, mq_receive.3, mq_send.3, nan.3, nextafter.3, posix_fallocate.3, posix_memalign.3, printf.3, qecvt.3, random.3, realpath.3, remainder.3, remquo.3, rint.3, round.3, scalb.3, scalbln.3, scanf.3, siginterrupt.3, signbit.3, sigset.3, sinh.3, sqrt.3, strcasecmp.3, strcat.3, strchr.3, strcmp.3, strcoll.3, strcpy.3, strfry.3, strpbrk.3, strsep.3, strspn.3, strstr.3, strtod.3, strtok.3, strtol.3, strtoul.3, strxfrm.3, tanh.3, tgamma.3, trunc.3, ttyslot.3, ualarm.3, usleep.3, wprintf.3, armscii-8.7, cp1251.7, iso_8859-10.7, iso_8859-11.7, iso_8859-13.7, iso_8859-14.7, iso_8859-3.7, iso_8859-5.7, iso_8859-6.7, iso_8859-8.7, koi8-u.7: tstamp
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-09-19 17:19:13 +00:00
|
|
|
.TH TTYSLOT 3 2010-09-20 "GNU" "Linux Programmer's Manual"
|
2004-11-03 13:51:07 +00:00
|
|
|
.SH NAME
|
|
|
|
ttyslot \- find the slot of the current user's terminal in some file
|
|
|
|
.SH SYNOPSIS
|
2007-07-08 12:11:40 +00:00
|
|
|
.BR "#include <unistd.h>" " /* on BSD-like systems, and Linux */"
|
2004-11-03 13:51:07 +00:00
|
|
|
.br
|
2006-01-13 09:44:53 +00:00
|
|
|
.BR "#include <stdlib.h>" " /* on System V-like systems */"
|
2004-11-03 13:51:07 +00:00
|
|
|
.sp
|
|
|
|
.B "int ttyslot(void);"
|
2007-07-08 12:11:40 +00:00
|
|
|
.sp
|
|
|
|
.in -4n
|
|
|
|
Feature Test Macro Requirements for glibc (see
|
|
|
|
.BR feature_test_macros (7)):
|
|
|
|
.in
|
|
|
|
.sp
|
|
|
|
.ad l
|
|
|
|
.BR ttyslot ():
|
2010-09-18 08:59:05 +00:00
|
|
|
.RS 4
|
|
|
|
_BSD_SOURCE ||
|
|
|
|
.br
|
2010-10-03 15:55:15 +00:00
|
|
|
_XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_\ <\ 500\ &&\ _XOPEN_SOURCE_EXTENDED
|
2010-09-18 08:59:05 +00:00
|
|
|
.RE
|
2007-07-08 12:11:40 +00:00
|
|
|
.ad b
|
2004-11-03 13:51:07 +00:00
|
|
|
.SH DESCRIPTION
|
|
|
|
The legacy function
|
|
|
|
.BR ttyslot ()
|
|
|
|
returns the index of the current user's entry in some file.
|
|
|
|
.LP
|
2007-04-12 22:42:49 +00:00
|
|
|
Now "What file?" you ask.
|
|
|
|
Well, let's first look at some history.
|
2004-11-03 13:51:07 +00:00
|
|
|
.SS "Ancient History"
|
|
|
|
There used to be a file
|
|
|
|
.I /etc/ttys
|
|
|
|
in Unix V6, that was read by the
|
|
|
|
.BR init (8)
|
|
|
|
program to find out what to do with each terminal line.
|
|
|
|
Each line consisted of three characters.
|
2008-06-09 15:49:35 +00:00
|
|
|
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".
|
2004-11-03 13:51:07 +00:00
|
|
|
The third character was an argument to
|
2007-12-10 15:28:06 +00:00
|
|
|
.BR getty (8)
|
2008-06-09 15:49:35 +00:00
|
|
|
indicating the sequence of line speeds to try (\(aq\-\(aq was: start trying
|
2007-04-12 22:42:49 +00:00
|
|
|
110 baud).
|
|
|
|
Thus a typical line was "18\-".
|
2008-06-09 15:49:35 +00:00
|
|
|
A hang on some line was solved by changing the \(aq1\(aq to a \(aq0\(aq,
|
2007-06-08 09:56:56 +00:00
|
|
|
signaling init, changing back again, and signaling init again.
|
2004-11-03 13:51:07 +00:00
|
|
|
.LP
|
|
|
|
In Unix V7 the format was changed: here the second character
|
|
|
|
was the argument to
|
2007-12-10 15:28:06 +00:00
|
|
|
.BR getty (8)
|
2008-06-09 15:49:35 +00:00
|
|
|
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)
|
2004-11-03 13:51:07 +00:00
|
|
|
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.
|
2006-01-13 09:44:53 +00:00
|
|
|
System V-like systems have
|
2004-11-03 13:51:07 +00:00
|
|
|
.I /etc/inittab
|
|
|
|
instead.
|
|
|
|
.SS "Ancient History (2)"
|
|
|
|
On the other hand, there is the file
|
|
|
|
.I /etc/utmp
|
2007-04-12 22:42:49 +00:00
|
|
|
listing the people currently logged in.
|
|
|
|
It is maintained by
|
2007-10-14 18:33:54 +00:00
|
|
|
.BR login (1).
|
2004-11-03 13:51:07 +00:00
|
|
|
It has a fixed size, and the appropriate index in the file was
|
|
|
|
determined by
|
2007-10-14 18:33:54 +00:00
|
|
|
.BR login (1)
|
2004-11-03 13:51:07 +00:00
|
|
|
using the
|
|
|
|
.BR ttyslot ()
|
|
|
|
call to find the number of the line in
|
2007-09-20 16:26:31 +00:00
|
|
|
.I /etc/ttys
|
2004-11-03 13:51:07 +00:00
|
|
|
(counting from 1).
|
|
|
|
.SS "The semantics of ttyslot"
|
|
|
|
Thus, the function
|
|
|
|
.BR ttyslot ()
|
2007-12-27 16:06:35 +00:00
|
|
|
returns the index of the controlling terminal of the calling process
|
2004-11-03 13:51:07 +00:00
|
|
|
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
|
2006-01-13 09:44:53 +00:00
|
|
|
file, but System V-like systems do not, and hence cannot refer to it.
|
2004-11-03 13:51:07 +00:00
|
|
|
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,
|
2006-01-13 09:44:53 +00:00
|
|
|
but \-1 on System V-like systems.
|
2007-05-19 04:30:20 +00:00
|
|
|
.SH "CONFORMING TO"
|
2007-12-14 10:39:16 +00:00
|
|
|
SUSv1; marked as LEGACY in SUSv2; removed in POSIX.1-2001.
|
2007-05-19 04:30:20 +00:00
|
|
|
SUSv2 requires \-1 on error.
|
2004-11-03 13:51:07 +00:00
|
|
|
.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>
|
2007-04-12 22:42:49 +00:00
|
|
|
as "/etc/ttys".
|
|
|
|
It returns 0 on error.
|
2004-11-03 13:51:07 +00:00
|
|
|
Since Linux systems do not usually have "/etc/ttys", it will
|
|
|
|
always return 0.
|
|
|
|
.LP
|
|
|
|
Minix also has
|
|
|
|
.IR fttyslot ( fd ).
|
2007-05-18 11:59:14 +00:00
|
|
|
.\" .SH HISTORY
|
|
|
|
.\" .BR ttyslot ()
|
|
|
|
.\" appeared in Unix V7.
|
2004-11-03 13:51:07 +00:00
|
|
|
.SH "SEE ALSO"
|
|
|
|
.BR getttyent (3),
|
|
|
|
.BR ttyname (3),
|
|
|
|
.BR utmp (5)
|