749 lines
19 KiB
Groff
749 lines
19 KiB
Groff
.TH TTY 4
|
|
.SH NAME
|
|
tty, termios \- terminals
|
|
.SH DESCRIPTION
|
|
The
|
|
.B tty
|
|
driver family takes care of all user input and output. It governs the
|
|
keyboard, the console, the serial lines, and pseudo ttys. Input on any of
|
|
these devices undergoes "input processing", and output undergoes "output
|
|
processing" according to the standard termios terminal interface.
|
|
.SS "Input processing"
|
|
Each terminal device has an input queue. This queue is used to store
|
|
preprocessed input characters, and to perform the backspacing and erase
|
|
functions. Some special characters like a newline make the contents of the
|
|
queue available to a process reading from the terminal. Characters up to
|
|
and including the newline, or another so-called "line break", may be read by
|
|
a process. The process need not read all characters at once. An input line
|
|
may be read byte by byte if one wants to. A line break just makes
|
|
characters available for reading, thats all.
|
|
.PP
|
|
When data is made available depends on whether the tty is in canonical mode
|
|
or not. In canonical mode the terminal processes input line by line. A
|
|
line ends with a newline
|
|
.RB ( NL ),
|
|
end-of-file
|
|
.RB ( EOF ),
|
|
or end-of-line
|
|
.RB ( EOL ).
|
|
Characters that have not been delimited by such a line break may be erased
|
|
one by one with the
|
|
.B ERASE
|
|
character or all at once with the
|
|
.B KILL
|
|
character. Once a line break is typed the characters become available to a
|
|
reading process and can no longer be erased. Once read they are removed
|
|
from the input queue. Several lines may be gathered in the input queue if
|
|
no reader is present to read them, but a new reader will only receive one
|
|
line. Two line breaks are never returned in one read call. The input queue
|
|
has a maximum length of
|
|
.B MAX_CANON
|
|
characters. Any more characters are discarded. One must use
|
|
.B ERASE
|
|
or
|
|
.B KILL
|
|
to make the terminal functioning again if the input queue fills up. If
|
|
nonblocking I/O is set then \-1 is returned with
|
|
.B errno
|
|
set to
|
|
.B EAGAIN
|
|
if the reader would otherwise be blocked.
|
|
.PP
|
|
In non-canonical mode (raw mode for short) all characters are immediately
|
|
available to the reader in principle. One may however tune the terminal to
|
|
bursty input with the
|
|
.B MIN
|
|
and
|
|
.B TIME
|
|
parameters, see the raw I/O parameters section below. In raw mode no
|
|
characters are discarded if the input queue threatens to overflow if the
|
|
device supports flow control.
|
|
.SS "Output processing"
|
|
Characters written to a terminal device may undergo output processing, which
|
|
is usually just inserting a carriage returns before newlines. A writer
|
|
may return before all characters are output if the characters can be stored
|
|
in the output buffers. If not then the writer may be blocked until space is
|
|
available. If non-blocking I/O is set then only the count of the number of
|
|
bytes that can be processed immediately is returned. If no characters can
|
|
be written at all then \-1 is returned with
|
|
.B errno
|
|
set to
|
|
.BR EAGAIN .
|
|
.SS "Special characters"
|
|
Some characters have special functions in some of the terminal modes. These
|
|
characters are as follows, with the MINIX 3 defaults shown in parentheses:
|
|
.TP 5
|
|
.BR INTR " (^?)"
|
|
Special input character that is recognized if
|
|
.B ISIG
|
|
is set. (For
|
|
.B ISIG
|
|
and other flags see the various modes sections below.) It causes a
|
|
.B SIGINT
|
|
signal to be sent to all processes in the terminal process group. (See the
|
|
section on session leaders below.)
|
|
.TP
|
|
.BR QUIT " (^\e)"
|
|
Special input character if
|
|
.B ISIG
|
|
is set. Causes a
|
|
.B SIGQUIT
|
|
signal to be sent to the terminal process group.
|
|
.TP
|
|
.BR ERASE " (^H)"
|
|
Special input character if
|
|
.B ICANON
|
|
is set. Erases the last character in the current line.
|
|
.TP
|
|
.BR KILL " (^U)"
|
|
Special input character if
|
|
.B ICANON
|
|
is set. Erases the entire line.
|
|
.TP
|
|
.BR EOF " (^D)"
|
|
Special input character if
|
|
.B ICANON
|
|
is set. It is a line break character that is not itself returned to a
|
|
reader. If EOF is typed with no input present then the read returns zero,
|
|
which normally causes the reader to assume that end-of-file is reached.
|
|
.TP
|
|
.BR CR " (^M)"
|
|
Special input character if
|
|
.B IGNCR
|
|
or
|
|
.B ICRNL
|
|
is set. It is a carriage return ('\er'). If
|
|
.B IGNCR
|
|
is set then
|
|
.B CR
|
|
is discarded. If
|
|
.B ICRNL
|
|
is set and
|
|
.B IGNCR
|
|
is not set then
|
|
.B CR
|
|
is changed into an
|
|
.B NL
|
|
and has the same function as
|
|
.BR NL.
|
|
.TP
|
|
.BR NL " (^J)"
|
|
Special input character if
|
|
.B ICANON
|
|
is set. It is both a newline ('\en') and a line break.
|
|
.br
|
|
Special output character if
|
|
.B OPOST
|
|
and
|
|
.B ONLCR
|
|
are set. A
|
|
.B CR NL
|
|
sequence is output instead of just
|
|
.BR NL .
|
|
(MINIX 3 specific, but almost mandatory on any UNIX-like system.)
|
|
.TP
|
|
.BR TAB " (^I)"
|
|
Special character on output if
|
|
.B OPOST
|
|
and
|
|
.B XTABS
|
|
are set. It is transformed into the number of spaces necessary to reach a
|
|
column position that is a multiple of eight. (Only needed for terminals
|
|
without hardware tabs.)
|
|
.TP
|
|
.BR EOL " (undefined)"
|
|
Special input character if
|
|
.B ICANON
|
|
is set. It is an additional line break.
|
|
.TP
|
|
.BR SUSP " (^Z)"
|
|
Special input character if job control is implemented and
|
|
.B ISIG
|
|
is set. It causes a
|
|
.B SIGTSTP
|
|
signal to be send to the terminal process group. (MINIX 3 does not have job
|
|
control.)
|
|
.TP
|
|
.BR STOP " (^S)"
|
|
Special input character if
|
|
.B IXON
|
|
is set. It suspends terminal output and is then discarded.
|
|
.TP
|
|
.BR START " (^Q)"
|
|
Special output character if
|
|
.B IXON
|
|
is set. It starts terminal output if suspended and is then discarded. If
|
|
.B IXANY
|
|
is also set then any other character also starts terminal output, but they
|
|
are not discarded.
|
|
.TP
|
|
.BR REPRINT " (^R)"
|
|
Special input character if
|
|
.B IEXTEN
|
|
and
|
|
.B ECHO
|
|
are set. Reprints the input queue from the last line break onwards. A
|
|
reprint also happens automatically if the echoed input has been messed up by
|
|
other output and
|
|
.B ERASE
|
|
is typed.
|
|
.TP
|
|
.BR LNEXT " (^V)"
|
|
Special input character if
|
|
.B IEXTEN
|
|
is set. It is the "literal next" character that causes the next character
|
|
to be input without any special processing.
|
|
.TP
|
|
.BR DISCARD " (^O)"
|
|
Special input character if
|
|
.B IEXTEN
|
|
is set. Causes output to be discarded until it is typed again. (Implemented
|
|
only under Minix-vmd.)
|
|
.PP
|
|
All of these characters except
|
|
.BR CR ,
|
|
.B NL
|
|
and
|
|
.B TAB
|
|
may be changed or disabled under MINIX 3. (Changes to
|
|
.B START
|
|
and
|
|
.B STOP
|
|
may be ignored under other termios implementations.) The
|
|
.B REPRINT
|
|
and
|
|
.B LNEXT
|
|
characters are MINIX 3 extensions that are commonly present in other
|
|
implementations. \s-2POSIX\s+2 is unclear on whether
|
|
.BR IEXTEN,
|
|
.BR IGNCR
|
|
and
|
|
.BR ICRNL
|
|
should be active in non-canonical mode, but under MINIX 3 they are.
|
|
.SS "Terminal attributes"
|
|
The attributes of a terminal, such as whether the mode should be canonical or
|
|
non-canonical, are controlled by routines that use the
|
|
.B termios
|
|
structure as defined in
|
|
.BR <termios.h> :
|
|
.PP
|
|
.RS
|
|
.nf
|
|
.ta +4n +10n +15n
|
|
struct termios {
|
|
tcflag_t c_iflag; /* input modes */
|
|
tcflag_t c_oflag; /* output modes */
|
|
tcflag_t c_cflag; /* control modes */
|
|
tcflag_t c_lflag; /* local modes */
|
|
speed_t c_ispeed; /* input speed */
|
|
speed_t c_ospeed; /* output speed */
|
|
cc_t c_cc[NCCS]; /* control characters */
|
|
};
|
|
.fi
|
|
.RE
|
|
.PP
|
|
The types
|
|
.BR tcflag ,
|
|
.B speed_t
|
|
and
|
|
.B cc_t
|
|
are defined in
|
|
.B <termios.h>
|
|
as unsigned integral types.
|
|
.SS "Input Modes"
|
|
The
|
|
.B c_iflag
|
|
field contains the following single bit flags that control input processing:
|
|
.TP 5
|
|
.B ICRNL
|
|
Map
|
|
.B CR
|
|
to
|
|
.B NL
|
|
on input.
|
|
.TP
|
|
.B IGNCR
|
|
Ignore
|
|
.B CR
|
|
on input. This flag overrides
|
|
.BR ICRNL .
|
|
.TP
|
|
.B INLCR
|
|
Map
|
|
.B NL
|
|
to
|
|
.B CR
|
|
on input. This is done after the
|
|
.B IGNCR
|
|
check.
|
|
.TP
|
|
.B IXON
|
|
Enable start/stop output control.
|
|
.TP
|
|
.B IXOFF
|
|
Enable start/stop input control. (Not implemented.)
|
|
.TP
|
|
.B IXANY
|
|
Allow any character to restart output. (MINIX 3 specific.)
|
|
.TP
|
|
.B ISTRIP
|
|
Strip characters to seven bits.
|
|
.TP
|
|
.B IGNPAR
|
|
Ignore characters with parity errors. (Not implemented.)
|
|
.TP
|
|
.B INPCK
|
|
Enable input parity checking. (Not implemented.)
|
|
.TP
|
|
.B PARMRK
|
|
Mark parity errors by preceding the faulty character with '\e377', '\e0'.
|
|
The character '\e377' is preceded by another '\e377' to avoid ambiguity.
|
|
(Not implemented.)
|
|
.TP
|
|
.B BRKINT
|
|
Send the signal
|
|
.B SIGINT
|
|
to the terminal process group when receiving a break condition. (Not
|
|
implemented.)
|
|
.TP
|
|
.B IGNBRK
|
|
Ignore break condition. If neither
|
|
.B BRKINT
|
|
or
|
|
.B IGNBRK
|
|
is set a break is input as a single '\e0', or if
|
|
.B PARMRK
|
|
is set as '\e377', '\e0', '\e0'.
|
|
(Breaks are always ignored.)
|
|
.TP
|
|
.B SCANCODES
|
|
Send input as keyboard scancodes rather than processed ASCII characters. This
|
|
flag only applies to consoles; to check whether the flag is supported use the
|
|
.B tcgetattr
|
|
function after setting it and test whether
|
|
.B c_iflag
|
|
still contains the
|
|
.B SCANCODES
|
|
flag. Scancodes are provided directly and without any processing. As a
|
|
consequence, the
|
|
.B ISTRIP
|
|
,
|
|
.B IGNCR
|
|
,
|
|
.B ICRNL
|
|
,
|
|
.B INLCR
|
|
,
|
|
.B ICANON
|
|
and
|
|
.B IEXTEN
|
|
flags no longer influence input if this flag is specified. However, they may
|
|
still influence echoing if enabled. (MINIX 3 specific.)
|
|
.SS "Output Modes"
|
|
The
|
|
.B c_oflag
|
|
field contains the following single bit flags that control output processing:
|
|
.TP
|
|
.B OPOST
|
|
Perform output processing. This flag is the "main switch" on output
|
|
processing. All other flags are MINIX 3 specific.
|
|
.TP
|
|
.B ONLCR
|
|
Transform an
|
|
.B NL
|
|
to a
|
|
.B CR NL
|
|
sequence on output. Note that a key labeled "RETURN" or "ENTER" usually
|
|
sends a
|
|
.BR CR .
|
|
In line oriented mode this is normally transformed into
|
|
.B NL
|
|
by
|
|
.BR ICRNL .
|
|
.B NL
|
|
is the normal UNIX line delimiter ('\en'). On output an
|
|
.B NL
|
|
is transformed into the
|
|
.B CR NL
|
|
sequence that is necessary to reach the first column of the next line.
|
|
(This is a common output processing function for UNIX-like systems, but not
|
|
always separately switchable by an
|
|
.B ONLCR
|
|
flag.)
|
|
.TP
|
|
.B XTABS
|
|
Transform a
|
|
.B TAB
|
|
into the number of spaces necessary to reach a column position that is a
|
|
multiple of eight.
|
|
.TP
|
|
.B ONOEOT
|
|
Discard
|
|
.B EOT
|
|
(^D) characters. (Minix-vmd only.)
|
|
.SS "Control Modes"
|
|
The
|
|
.B c_cflag
|
|
field contains the following single bit flags and bit field for basic
|
|
hardware control:
|
|
.TP
|
|
.B CLOCAL
|
|
Ignore modem status lines.
|
|
.TP
|
|
.B CREAD
|
|
Enable receiver. (The receiver is always enabled.)
|
|
.TP
|
|
.B CSIZE
|
|
Number of bits per byte.
|
|
.B CSIZE
|
|
masks off the values
|
|
.BR CS5 ,
|
|
.BR CS6 ,
|
|
.BR CS7
|
|
and
|
|
.BR CS8
|
|
that indicate that 5, 6, 7 or 8 bits are used.
|
|
.TP
|
|
.B CSTOPB
|
|
Send two stop bits instead of one. Two stop bits are normally used at 110
|
|
baud or less.
|
|
.TP
|
|
.B PARENB
|
|
Enable parity generation.
|
|
.TP
|
|
.B PARODD
|
|
Generate odd parity if parity is generated, otherwise even parity.
|
|
.TP
|
|
.B HUPCL
|
|
Drop the modem control lines on the last close of the terminal line. (Not
|
|
implemented.)
|
|
.SS "Local Modes"
|
|
The
|
|
.B c_lflag
|
|
field contains the following single bit flags that control various functions:
|
|
.TP
|
|
.B ECHO
|
|
Enable echoing of input characters. Most input characters are echoed as
|
|
they are. Control characters are echoed as
|
|
.BI "^" X
|
|
where
|
|
.I X
|
|
is the letter used to say that the control character is
|
|
.BI CTRL\- X\fR.
|
|
The
|
|
.BR CR ,
|
|
.BR NL
|
|
and
|
|
.BR TAB
|
|
characters are echoed with their normal effect unless they are escaped by
|
|
.BR LNEXT .
|
|
.TP
|
|
.B ECHOE
|
|
If
|
|
.B ICANON
|
|
and
|
|
.B ECHO
|
|
are set then echo
|
|
.B ERASE
|
|
and
|
|
.B KILL
|
|
as one or more backspace-space-backspace sequences to wipe out the last
|
|
character or the entire line, otherwise they are echoed as they are.
|
|
.TP
|
|
.B ECHOK
|
|
If
|
|
.B ICANON
|
|
and
|
|
.B ECHO
|
|
are set and
|
|
.B ECHOE
|
|
is not set then output an
|
|
.B NL
|
|
after the
|
|
.B KILL
|
|
character. (For hardcopy terminals it is best to unset
|
|
.B ECHOE
|
|
and to set
|
|
.BR ECHOK .)
|
|
.TP
|
|
.B ECHONL
|
|
Echo
|
|
.B NL
|
|
even if
|
|
.B ECHO
|
|
is not set, but
|
|
.B ICANON
|
|
is set.
|
|
.TP
|
|
.B ICANON
|
|
Canonical input. This enables line oriented input and erase and kill
|
|
processing.
|
|
.TP
|
|
.B IEXTEN
|
|
Enable implementation defined input extensions.
|
|
.TP
|
|
.B ISIG
|
|
Enable the signal characters
|
|
.BR INTR ,
|
|
.BR QUIT
|
|
and
|
|
.BR SUSP .
|
|
.TP
|
|
.B NOFLSH
|
|
Disable the flushing of the input and output queues that is normally done if
|
|
a signal is sent.
|
|
.TP
|
|
.B TOSTOP
|
|
Send a
|
|
.B SIGTTOU
|
|
signal if job control is implemented and a background process tries to
|
|
write. (MINIX 3 has no job control.)
|
|
.SS "Input and output speed"
|
|
The input and output speed are encoded into the
|
|
.B c_ispeed
|
|
and
|
|
.B c_ospeed
|
|
fields.
|
|
.B <termios.h>
|
|
defines the symbols
|
|
.BR B0 ,
|
|
.BR B50 ,
|
|
.BR B75 ,
|
|
.BR B110 ,
|
|
.BR B134 ,
|
|
.BR B150 ,
|
|
.BR B200 ,
|
|
.BR B300 ,
|
|
.BR B600 ,
|
|
.BR B1200 ,
|
|
.BR B1800 ,
|
|
.BR B2400 ,
|
|
.BR B4800 ,
|
|
.BR B9600 ,
|
|
.BR B19200 ,
|
|
.BR B38400 ,
|
|
.BR B57600
|
|
and
|
|
.BR B115200
|
|
as values used to indicate the given baud rates. The zero baud rate,
|
|
.BR B0 ,
|
|
if used for the input speed causes the input speed to be equal to the
|
|
output speed. Setting the output speed to zero hangs up the line. One
|
|
should use the functions
|
|
.BR cfgetispeed() ,
|
|
.BR cfgetospeed() ,
|
|
.BR cfsetispeed()
|
|
and
|
|
.BR cfsetospeed()
|
|
to get or set a speed, because the
|
|
.B c_ispeed
|
|
and
|
|
.B c_ospeed
|
|
fields may not be visible under other implementations. (The
|
|
.B c_ispeed
|
|
and
|
|
.B c_ospeed
|
|
fields and the
|
|
.B B57600
|
|
and
|
|
.B B115200
|
|
symbols are MINIX 3 specific.)
|
|
.SS "Special characters"
|
|
The
|
|
.B c_cc
|
|
array contains the special characters that can be modified. The array has
|
|
length
|
|
.B NCCS
|
|
and is subscripted by the symbols
|
|
.BR VEOF ,
|
|
.BR VEOL ,
|
|
.BR VERASE ,
|
|
.BR VINTR ,
|
|
.BR VKILL ,
|
|
.BR VMIN ,
|
|
.BR VQUIT ,
|
|
.BR VTIME ,
|
|
.BR VSUSP ,
|
|
.BR VSTART ,
|
|
.BR VSTOP ,
|
|
.BR VREPRINT ,
|
|
.BR VLNEXT
|
|
and
|
|
.BR VDISCARD .
|
|
All these symbols are defined in
|
|
.BR <termios.h> .
|
|
Some implementations may give the same values to the
|
|
.B VMIN
|
|
and
|
|
.B VTIME
|
|
subscripts and the
|
|
.B VEOF
|
|
and
|
|
.B VEOL
|
|
subscripts respectively, and may ignore changes to
|
|
.B START
|
|
and
|
|
.BR STOP .
|
|
(Under MINIX 3 all special characters have their own
|
|
.I c_cc
|
|
slot and can all be modified.)
|
|
.SS "Raw I/O Parameters"
|
|
The
|
|
.B MIN
|
|
and
|
|
.B TIME
|
|
parameters can be used to adjust a raw connection to bursty input.
|
|
.B MIN
|
|
represents a minimum number of bytes that must be received before a read
|
|
call returns.
|
|
.B TIME
|
|
is a timer of 0.1 second granularity that can be used to time out a read.
|
|
Setting either of these parameters to zero has special meaning, which leads
|
|
to the following four possibilities:
|
|
.TP 5
|
|
.B "MIN > 0, TIME > 0"
|
|
.B TIME
|
|
is an inter-byte timer that is started (and restarted) when a byte is
|
|
received. A read succeeds when either the minimum number of characters
|
|
is received or the timer expires. Note that the timer starts
|
|
.B after
|
|
the first character, so the read returns at least one byte.
|
|
.TP
|
|
.B "MIN > 0, TIME = 0"
|
|
Now the timer is disabled, and a reader blocks indefinitely until at least
|
|
.B MIN
|
|
characters are received.
|
|
.TP
|
|
.B "MIN = 0, TIME > 0"
|
|
.B TIME
|
|
is now a read timer that is started when a read is executed. The read will
|
|
return if the read timer expires or if at least one byte is input. (Note
|
|
that a value of zero may be returned to the reader.)
|
|
.TP
|
|
.B "MIN = 0, TIME = 0"
|
|
The bytes currently available are returned. Zero is returned if no bytes
|
|
are available.
|
|
.SS "User Level Functions"
|
|
Termios attributes are set or examined, and special functions can be
|
|
performed by using the functions described in
|
|
.BR termios (3).
|
|
.SS "Session Leaders and Process Groups"
|
|
With the use of the
|
|
.B setsid()
|
|
function can a process become a session leader. A session leader forms a
|
|
process group with a process group id equal to the process id of the session
|
|
leader. If a session leader opens a terminal device file then this terminal
|
|
becomes the controlling tty of the session leader. Unless the terminal is
|
|
already the controlling tty of another process, or unless the
|
|
.B O_NOCTTY
|
|
flag is used to prevent the allocation of a controlling tty. The process
|
|
group of the session leader is now remembered as the terminal process group
|
|
for signals sent by the terminal driver. All the children and grandchildren
|
|
of the session leader inherit the controlling terminal and process group
|
|
until they themselves use
|
|
.BR setsid() .
|
|
.PP
|
|
The controlling tty becomes inaccessible to the children of the session
|
|
leader when the session leader exits, and a hangup signal is sent to all
|
|
the members of the process group. The input and output queues are flushed
|
|
on the last close of a terminal and all attributes are reset to the default
|
|
state.
|
|
.PP
|
|
A special device
|
|
.B /dev/tty
|
|
is a synonym for the controlling tty of a process. It allows a process to
|
|
reach the terminal even when standard input, output and error are
|
|
redirected. Opening this device can also be used as a test to see if a
|
|
process has a controlling tty or not.
|
|
.PP
|
|
For MINIX 3 a special write-only device
|
|
.B /dev/log
|
|
exists for processes that want to write messages to the system console.
|
|
Unlike the console this device is still accessible when a session leader
|
|
exits.
|
|
.PP
|
|
Minix-vmd also has a
|
|
.B /dev/log
|
|
device, but this device is read-write. All messages written to the log
|
|
device or to the console when X11 is active can be read from
|
|
.BR /dev/log .
|
|
The system tries to preserve the log buffer over a reboot so that panic
|
|
messages reappear in the log if the system happens to crash.
|
|
.SS "Pseudo Terminals"
|
|
Pseudo ttys allow a process such as a remote login daemon to set up a
|
|
terminal for a remote login session. The login session uses a device like
|
|
.B /dev/ttyp0
|
|
for input and output, and the remote login daemon uses the device
|
|
.B /dev/ptyp0
|
|
to supply input to or take output from the login session and transfer this
|
|
to or from the originating system. So the character flow may be: Local
|
|
user input sent to the remote system is written to
|
|
.B /dev/ptyp0
|
|
by the remote login daemon, undergoes input processing and appears on
|
|
.B /dev/ttyp0
|
|
as input to the login session. Output from the login session to
|
|
.B /dev/ttyp0
|
|
undergoes output processing, is read from
|
|
.B /dev/ptyp0
|
|
by the remote login daemon and is send over to the local system to be
|
|
displayed for the user. (So there are only four data streams to worry about
|
|
in a pseudo terminal.)
|
|
.PP
|
|
A pseudo terminal can be allocated by trying to open all the controlling
|
|
devices
|
|
.BI /dev/pty nn
|
|
one by one until it succeeds. Further opens will fail once a pty is open.
|
|
The process should now fork, the child should become session leader, open
|
|
the tty side of the pty and start a login session.
|
|
.PP
|
|
If the tty side is eventually closed down then reads from the pty side will
|
|
return zero and writes return \-1 with
|
|
.B errno
|
|
set to
|
|
.BR EIO .
|
|
If the pty side is closed first then a
|
|
.B SIGHUP
|
|
signal is sent to the session leader and further reads from the tty side
|
|
return zero and writes return \-1 with
|
|
.B errno
|
|
set to
|
|
.BR EIO .
|
|
(Special note: A line erase may cause up to three times the size of the
|
|
tty input queue to be sent to the pty reader as backspace overstrikes. Some
|
|
of this output may get lost if the pty reader cannot accept it all at once
|
|
in a single read call.)
|
|
.SH FILES
|
|
The list below shows all devices that MINIX 3 and Minix-vmd have. Not all of
|
|
these devices are configured in by default, as indicated by the numbers
|
|
(i/j/k, l/m/n) that tell the minimum, default and maximum possible number of
|
|
these devices for MINIX 3 (i/j/k) and Minix-vmd (l/m/n).
|
|
.TP 20
|
|
.B /dev/console
|
|
System console.
|
|
.TP
|
|
.B /dev/ttyc[1-7]
|
|
Virtual consoles. (0/1/7, 0/1/7)
|
|
.TP
|
|
.BR /dev/log
|
|
Console log device.
|
|
.TP
|
|
.B /dev/tty0[0-3]
|
|
Serial lines. (0/2/2, 4/4/4)
|
|
.TP
|
|
.B /dev/tty[p-w][0-f]
|
|
Pseudo ttys. (0/0/64, 1/32/128)
|
|
.TP
|
|
.B /dev/pty[p-w][0-f]
|
|
Associated pseudo tty controllers.
|
|
.SH "SEE ALSO"
|
|
.BR stty (1),
|
|
.BR termios (3),
|
|
.BR setsid (2),
|
|
.BR read (2),
|
|
.BR write (2).
|
|
.SH BUGS
|
|
A fair number of flags are not implemented under MINIX 3 (yet). Luckily they
|
|
are very limited utility and only apply to RS-232, not to the user interface.
|
|
.SH AUTHOR
|
|
Kees J. Bot (kjb@cs.vu.nl)
|