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Defines the structure of the
termio file, which provides the terminal interface for Version 2
compatibility.
The
/usr/include/sys/termio.h file contains the
termio structure, which defines special characters as well as the
basic input, output, control, and line discipline modes. The
termio.h file is provided for compatibility with Version 2
applications.
Version 2 applications that
include the termio.h file can use the Version 2 terminal
interface provided by the POSIX line discipline. The following Version
2 terminal interface operations are not supported by the POSIX line
discipline:
- Terminal Paging
(TCGLEN ioctl and TCSLEN ioctl)
- Terminal Logging
(TCLOG ioctl)
- Enhanced Edit Line Discipline
(LDSETDT ioctl and LDGETDT ioctl)
The termio structure
in the termio.h file contains the following fields:
- c_iflag
- Describes the basic terminal input control. The initial
input-control value is all bits clear. The possible input modes
are:
- IGNBRK
- Ignores the break condition. In the context of asynchronous serial
data transmission, a break condition is defined as a sequence of
zero-valued bits that continues for more than the time required to send 1
byte. The entire sequence of zero-valued bits is interpreted as a
single break condition, even if it continues for an amount of time equivalent
to more than one byte. If the IGNBRK flag is set, a break
condition detected on input is ignored, which means that the break condition
is not put on the input queue and therefore not read by any process.
- BRKINT
- Interrupts the signal on the break condition. If the
IGNBRK flag is not set and the BRKINT flag is set, the
break condition flushes the input and output queues. If the terminal is
the controlling terminal of a foreground process group, the break condition
generates a single SIGINT signal to that foreground process
group. If neither the IGNBRK nor the BRKINT flag
is set, a break condition is read as a single \0. If the
PARMRK flag is set, a break condition is read as \377, \0,
\0.
- IGNPAR
- Ignores characters with parity errors. If this flag is set, a byte
with a framing or parity error (other than break) is ignored.
- PARMRK
- Marks parity errors. If the PARMRK flag is set and the
IGNPAR flag is not set, a byte with a framing or parity error
(other than break) is given to the application as the three-character sequence
\377, \0, x, where \377, \0 is a two-character flag preceding each
sequence and x is the data of the character received in
error. To avoid ambiguity in this case, if the ISTRIP flag
is not set, a valid character of \377 is given to the application as \377,
\377. If neither the IGNPAR nor the PARMRK flag
is set, a framing or parity error (other than break) is given to the
application as a single character, \0.
- INPCK
- Enables input parity checking. If this flag is set, input parity
checking is enabled. If not set, input parity checking is
disabled. This allows for output parity generation without input parity
errors.
- ISTRIP
- Strips characters. If this flag is set, valid input characters are
first stripped to 7 bits; otherwise, all 8 bits are processed.
- INLCR
- Maps a new-line character (NL) to a carriage return (CR) on input.
If this flag is set, a received NL character is translated into a CR
character.
- IGNCR
- Ignores a CR character. If this flag is set, a received CR
character is ignored and not read.
- ICRNL
- Maps a CR character to an NL character on input. If the
ICRNL flag is set and the IGNCR flag is not set, a
received CR character is translated into an NL character.
- IUCLC
- Maps uppercase to lowercase on input. If this flag is set, a
received uppercase, alphabetic character is translated into the corresponding
lowercase character.
- IXON
- Enables start and stop output control. If this flag is set, a
received STOP character suspends output and a received START character
restarts output. When the IXON flag is set, START and STOP
characters are not read, but merely perform flow-control functions.
When the IXON flag is not set, the START and STOP characters are
read.
- IXANY
- Enables any character to restart output. If this flag is set, any
input character restarts output that was suspended.
- IXOFF
- Enables start-and-stop input control. If this flag is set, the
system transmits a STOP character when the input queue is nearly full and a
START character when enough input has been read that the queue is nearly empty
again.
-
-
- c_oflag
- Specifies how the system treats output. The initial output-control
value is "all bits clear". The possible output modes are:
- OPOST
- Post processes output. If this flag is set, output characters are
post-processed as indicated by the remaining flags; otherwise, characters
are transmitted without change.
- OLCUC
- Maps lowercase to uppercase on output. If this flag is set, a
lowercase alphabetic character is transmitted as the corresponding uppercase
character. This function is often used in conjunction with the
IUCLC input mode.
- ONLCR
- Maps NL to CR-NL on output. If this flag is set, the NL character
is transmitted as the CR-NL character pair.
- OCRNL
- Maps CR to NL on output. If this flag is set, the CR character is
transmitted as the NL character.
- ONOCR
- Indicates no CR output at column 0 (first position). If this flag
is set, no CR character is transmitted when at column 0 (first
position).
- ONLRET
- NL performs the CR function. If this flag is set, the NL character
is assumed to do the carriage-return function. The column pointer is
set to 0, and the delay specified for carriage return is used. If
neither the ONLCR, OCRNL, ONOCR, nor
ONLRET flag is set, the NL character is assumed to do the line-feed
function only. The column pointer remains unchanged. The column
pointer is also set to 0 if the CR character is actually transmitted.
The delay bits specify how long a
transmission stops to allow for mechanical or other movement when certain
characters are sent to the terminal. The actual delays depend on line
speed and system load.
- OFILL
- Uses fill characters for delay. If this flag is set, fill
characters are transmitted for a delay instead of a timed delay. This
is useful for high baud rate terminals that need only a minimal delay.
- OFDEL
- If this flag is set, the fill character is DEL. If this flag is not
set, the fill character is NULL.
- NLDLY
- Selects the new-line character delays. This is the mask to use
before comparing to NL0 and NL1:
- NL0
- Specifies no delay.
- NL1
- Specifies one delay of approximately 0.10 seconds. If the
ONLRET flag is set, the carriage-return delays are used instead of
the new-line delays. If the OFILL flag is set, two fill
characters are transmitted.
-
-
- CRDLY
- Selects the carriage-return delays. This is the mask to use before
comparing to CR0, CR1, CR2, and CR3:
- CR0
- Specifies no delay.
- CR1
- Specifies that the delay is dependent on the current column
position. If the OFILL flag is set, two fill characters are
transmitted.
- CR2
- Specifies a delay of approximately 0.10 seconds. If the
OFILL flag is set, this delay transmits four fill
characters.
- CR3
- Specifies one delay of approximately 0.15 seconds.
-
-
- TABDLY
- Selects the horizontal-tab delays. This is the mask to use before
comparing to TAB0, TAB1, TAB2, and TAB3. If the OFILL flag
is set, any of these delays (except TAB3) transmit two fill characters:
- TAB0
- Specifies no delay.
- TAB1
- Specifies that the delay is dependent on the current column
position. If the OFILL flag is set, two fill characters are
transmitted.
- TAB2
- Specifies a delay of approximately 0.10 seconds.
- TAB3
- Specifies that tabs are to be expanded into spaces.
-
-
- BSDLY
- Selects the backspace delays. This is the mask to use before
comparing to BS0 and BS1:
- BS0
- Specifies no delay.
- BS1
- Specifies a delay of approximately 0.05 seconds. If the
OFILL flag is set, this delay transmits one fill character.
-
-
- VTDLY
- Selects the vertical-tab delays. This is the mask to use before
comparing to VT0 and VT1:
- VT0
- Specifies no delay.
- VT1
- Specifies one delay of approximately 2 seconds.
-
-
- FFDLY
- Selects the form-feed delays. This is a mask to use before
comparing to FF0 and FF1:
- FF0
- Specifies no delay.
- FF1
- Specifies a delay of approximately 2 seconds.
-
-
-
-
- c_cflag
- Describes the hardware control of the terminal. In addition to the
basic control modes, this field uses the following control characters:
- CBAUD
- Specifies baud rate. These bits specify the baud rate for a
connection. For any particular hardware, impossible speed changes are
ignored.
- B0
- Specifies a zero baud rate which is used to hang up the connection.
If B0 is specified, the `data terminal ready' signal is not
asserted. As a result, the line is usually disconnected. This
delay transmits two fill characters. Normally, this disconnects the
line.
- B50
- Specifies 50 baud.
- B75
- Specifies 75 baud.
- B110
- Specifies 110 baud.
- B134
- Specifies 134.5 baud.
- B150
- Specifies 150 baud.
- B200
- Specifies 200 baud.
- B300
- Specifies 300 baud.
- B600
- Specifies 600 baud.
- B1200
- Specifies 1200 baud.
- B1800
- Specifies 1800 baud.
- B2400
- Specifies 2400 baud.
- B4800
- Specifies 4800 baud.
- B9600
- Specifies 9600 baud.
- B19200
- Specifies 19,200 baud.
- B38400
- Specifies 38,400 baud.
- EXTA
- Specifies External A.
- EXTB
- Specifies External B.
-
-
- CSIZE
- Specifies the character size. These bits specify the character
size, in bits, for both transmit and receive operations. The character
size does not include the parity bit, if one is used:
- CS5
- 5 bits
- CS6
- 6 bits
- CS7
- 7 bits
- CS8
- 8 bits
-
-
- CSTOPB
- Specifies the number of stop bits. If this flag is set, 2 stop bits
are sent; otherwise, only 1 stop bit is sent.
- CREAD
- Enables the receiver. If this flag is set, the receiver is
enabled. Otherwise, characters are not received.
- PARENB
- Enables parity. If this flag is set, parity generation and
detection is enabled and a parity bit is added to each character.
- PARODD
- Specifies odd parity. If parity is enabled, the PARODD
flag specifies odd parity if set. If parity is enabled and the
PARODD flag is not set, even parity is used.
- HUPCL
- Hangs up on last close. If this flag is set, the line is
disconnected when the last process closes the line or when the process
terminates (when the `data terminal ready' signal drops).
- CLOCAL
- Specifies a local line. If this flag is set, the line is assumed to
have a local, direct connection with no modem control. If not set,
modem control (dial-up) is assumed.
-
-
- c_lflag
- Controls various terminal functions. The initial value after an
open is "all bits clear." This field uses the following mask name
symbols:
- ISIG
- Enables signals. If this flag is set, each input character is
checked against the INTR and QUIT special control characters. If an
input character matches one of these control characters, the function
associated with that character is performed. If the ISIG
function is not set, checking is not done.
- ICANON
- Enables canonical input. If this flag is set, it turns on canonical
processing, which enables the erase and kill edit functions as well as the
assembly of input characters into lines delimited by NL, EOF, and EOL
characters. If the ICANON flag is not set, read requests are
satisfied directly from the input queue. In this case, a read request
is not satisfied until one of the following conditions is met:
- The minimum number of
characters specified by the MIN value are received.
- The time-out value specified
by the TIME value has expired since the last character was
received.
As a result bursts of input can be
read, while still allowing single-character input. The MIN
and TIME values are stored in the positions for the EOF and EOL
characters, respectively. The character values of MIN and
TIME are converted to their ascii equivalents to get the numeric
value. The time value represents tenths of seconds.
- XCASE
- Enables canonical uppercase and lowercase presentation. If this
flag is set along with the ICANON flag, an uppercase letter (or the
uppercase letter translated to lowercase by the IUCLC input mode)
is accepted on input by preceding it with a \ (backslash) character.
The output is then also preceded by a backslash character. In this
mode, the output generates and the input accepts the following escape
sequences:
- For
- Use
- ` (grave)
- \ `
- |
- \ !
- ~
- \ ^
- {
- \ (
- }
- \ )
- \
- \ \
For example, A is input as
\a, \n as \\n, and \N as \\\n.
-
-
- NOFLSH
- Disables queue flushing. If this flag is set, the normal flushing
of the input and output queues associated with the INTR and QUIT characters is
not done.
- ECHO
- Enables echo. If this flag is set, characters are echoed as they
are received.
When the ICANON flag is set, the following echo functions are
possible:
- ECHOE
- Echoes the erase character as Backspace-Space-Backspace. If
the ECHO and ECHOE flags are both set, the ERASE
character is echoed as one or more ASCII Backspace-Space-Backspace sequences,
which clears the last characters from the screen.
- ECHOK
- Echoes the NL character after kill. If the ECHOK flag is
set, the NL character is echoed after the kill character is received.
This emphasizes that the line is deleted.
- ECHONL
- Echoes the NL character. If the ECHONL flag is set, the
NL character is echoed even if the ECHO flag is not set.
This is useful for terminals that are set to "local echo" (also referred to as
"half-duplex").
-
-
- c_cc
- Specifies an array that defines the special control characters. The
relative positions and initial values for each function are:
- VINTR
- Indexes the INTR special character (Ctrl-c), which is recognized on input
if the ISIG flag is set. The INTR character generates a
SIGINT signal, which is sent to all processes in the foreground
process group for which the terminal is the controlling terminal. If
the ISIG flag is set, the INTR character is discarded when
processed.
- VQUIT
- Indexes the QUIT special character (Ctrl-\), which is recognized on input
if the ISIG flag is set. The QUIT character generates a
SIGQUIT signal, which is sent to all processes in the foreground
process group for which the terminal is the controlling terminal, and writes a
core image file into the current working directory. If the
ISIG flag is set, the QUIT character is discarded when
processed.
- VERASE
- Indexes the ERASE special character (Backspace), which is recognized on
input if the ICANON flag is set. The ERASE character does
not erase beyond the beginning of the line as delimited by a NL, EOL, EOF, or
EOL2 character. If the ICANON flag is set, the ERASE
character is discarded when processed.
- VKILL
- Indexes the KILL special character (Ctrl-u), which is recognized on input
if the ICANON flag is set. The KILL character deletes the
entire line, as delimited by an NL, EOL, EOF, or EOL2 character. If the
ICANON flag is set, the KILL character is discarded when
processed.
- VEOF
- Indexes the EOF special character (Ctrl-d), which is recognized on input
if the ICANON flag is set. When EOF is received, all the
characters waiting to be read are immediately passed to the process, without
waiting for a new line, and the EOF is discarded. If the EOF is
received at the beginning of a line (no characters are waiting), a character
count of zero is returned from the read, indicating an end-of-file. If
the ICANON flag is set, the EOF character is discarded when
processed.
- VEOL
- Indexes the EOL special character (Ctrl-@ or ASCII NULL), which is
recognized on input if the ICANON flag is set. EOL is an
additional line delimiter, like NL, and is not normally used.
- VEOL2
- Indexes the EOL2 special character (Ctrl-@ or ASCII NULL), which is
recognized on input if the ICANON flag is set. EOL2 is
another additional line delimiter, like NL, and is not normally used.
- VMIN
- Indexes the MIN value, which is not a special character.
The use of the MIN value is described in the discussion of non-canonical mode input processing in "POSIX
(termios.h File) Line Discipline" in AIX 5L Version 5.1
General Programming Concepts: Writing and Debugging
Programs.
- VTIME
- Indexes the TIME value, which is not a special character. The use
of the TIME value is described in the discussion of non-canonical mode input processing in "POSIX
(termios.h File) Line Discipline" in AIX 5L Version 5.1
General Programming Concepts: Writing and Debugging
Programs.
The character values for the
following control characters can be changed:
| INTR
| ERASE
| EOF
| EOL2
|
| QUIT
| KILL
| EOL
|
The ERASE, KILL, and EOF
characters can also be escaped (preceded with a backslash) so that no special
processing is done.
-
-
The primary ioctl subroutines
have the form:
ioctl (FileDescriptor, Command, Structure)
struct termio *Structure;
The operations using this form
are:
- TCGETA
- Gets the parameters associated with the terminal and stores them in the
termio structure referenced by the Structure
parameter.
- TCSETA
- Sets the parameters associated with the terminal from the structure
referenced by the Structure parameter. The change is
immediate.
- TCSETAF
- Waits for the output to drain, and then flushes the input queue and sets
the new parameters.
- TCSETAW
- Waits for the output to drain before setting the new parameters.
This form should be used when changing parameters that will affect
output.
Other ioctl subroutines have the
form:
ioctl (FileDescriptor, Command, Value)
int Value;
The operations using this form
are:
Attention: If
the user writes an application that performs a TCSBRK operation
followed by a TCFLSH operation prior to closing a port, the last
data left in the concentrator box on the 64-port adapter is lost.
However, no problem occurs if an SIO, 8-port, or 16-port adapter is
used.
- TCSBRK
- Waits for the output to drain. If the Value parameter
has a value of 0, it sends a break of 0.25 seconds. A nonzero
value causes a break condition of that many milliseconds.
- TCSBREAK
- Waits for the output to drain. If the Value parameter
has a value of 0, it sends a break of .25 seconds. A nonzero
value causes a break condition of that many milliseconds.
- TCXONC
- Starts and stops control. If the Value parameter has a
value of 0, it suspends output. If the Value parameter has a
value of 1, it restarts suspended output. If the Value
parameter has a value of 2, it blocks input. If the Value
parameter has a value of 3, it unblocks input.
- TCFLSH
- If the Value parameter has a value of 0, it flushes the input
queue. If the Value parameter has a value of 1, it flushes
the output queue. If the Value parameter has a value of 2,
it flushes both the input and output queues.
Another form for ioctl
subroutines is:
ioctl (FileDescriptor, Command, Structure)
struct csmap* Structure;
- TCSCSMAP
- Sets the code set map from the structure referenced by the structure
parameter and rejects any invalid map (any map with 0 length/width or a length
greater than MB_LEN_MAX). The
/usr/include/sys/tty.h file contains the structure used for
TCSCSMAP and TCGCSMAP operations.
- TCGCSMAP
- Returns a copy of the current code set map in the structure referenced by
the structure parameter. The /usr/include/sys/tty.h
file contains the structure used for TCSCSMAP and
TCGCSMAP operations.
The following ioctl operations
are used for trusted communications path operations:
- TCSAK
- Points to an integer that enables the Secure Attention Key (SAK) sequence
(Ctrl-X, Ctrl-R) to provide a clean terminal to which only trusted processes
can read or write. When SAK is enabled and the user types this
sequence, all processes that are currently running are ended. The
TCSAKON operation turns the SAK sequence on; the
TCSAKOFF operation turns the SAK sequence off.
- TCQSAK
- Queries the state (TCSAKON or TCSAKOFF) of the SAK
sequence.
- TCTRUST
- Sets a bit by which another process can query, (with the
TCQTRUST operation), the state of the terminal,
(TCTRUSTED or TCUNTRUSTED).
- TCQTRUST
- Queries the state of the terminal (TCTRUSTED or
TCUNTRUSTED).
This file is for compatibility
with Version 2.
This file is part of Base
Operating System (BOS) Runtime.
The fork subroutine, ioctl subroutine, setpgrp subroutine, sigvec subroutine.
The csh command, getty command, stty command, tset command.
The tty
Subsystem Overview in AIX 5L Version 5.1 General Programming
Concepts: Writing and Debugging Programs.
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