| Field Descriptions |
|
|---|
| 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 one 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 it is not put on the input queue and therefore not read by any process. |
| BRKINT |
Signal interrupt 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 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, or if the PARMRK flag is set, 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 CR character. If this flag is set, a received CR character is ignored and not read. |
| ICRNL |
Maps a CR character to the NL character on input. If the ICRNL flag is set and the IGNCR flag is not set, a received CR character is translated into a 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. |
| IMAXBEL |
Echoes the ASCII BEL character if the input stream overflows. Further input is not stored, but input already present in the input stream is not lost. If this flag is not set, no BEL character is echoed; the input in the input queue is discarded if the input stream overflows. This function also requires the IEXTEN bit to be set. |
|
| 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 flag 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. If this flag is set, no CR character is transmitted when at column 0 (first position). |
| ONLRET |
NL performs 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 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 a 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, this delay transmits two fill characters. |
| CR2 |
Specifies a delay of approximately 0.10 seconds. If the OFILL flag is set, this
delay transmits four fill characters. |
| CR3 |
Specifies a 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 a delay of approximately 2 seconds. |
|
| FFDLY |
Selects the form-feed delays. This is the 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.
| B50 |
50 baud. |
| B75 |
75 baud. |
| B110 |
110 baud. |
| B134 |
134.5 baud. |
| B150 |
150 baud. |
| B200 |
200 baud. |
| B300 |
300 baud. |
| B600 |
600 baud. |
| B1200 |
1200 baud. |
| B1800 |
1800 baud. |
| B2400 |
2400 baud. |
| B4800 |
4800 baud. |
| B9600 |
9600 baud. |
| B19200 |
19200 baud. |
| B38400 |
38400 baud. |
| EXTA |
External A. |
| EXTB |
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 number of stop bits. If this flag is set, 2 stop bits are sent; otherwise,
only 1 stop bit is sent. |
| CREAD |
Enables 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. |
| CIBAUD |
Specifies the input baud rate if different from the output rate. |
| PAREXT |
Specifies extended parity for mark and space parity. |
|
| c_lflag |
Controls various terminal functions. The initial value after an open is "all bits
clear." In addition to the basic modes, this field uses the following mask name symbols:
| ISIG |
Enables signals. If this flag is set, each input character is checked against the
INTR, QUIT, SUSP, and DSUSP special control characters. If an input character matches one of
these control characters, the function associated with that character is performed. If the
ISIG flag 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 MIN are
received.
- The time-out value specified by TIME has expired since
the last character was received. This allows bursts of input to 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, QUIT, and SUSP characters is not done. |
| FLUSHO |
Flushes the output. When this bit is set by typing the FLUSH character, data written
to the terminal is discarded. A terminal can cancel the effect of typing the FLUSH character by
clearing this bit. |
| PENDIN |
Reprints pending input. If this flag is set, any input that is pending after a switch
from raw to canonical mode is re-input the next time a read operation becomes pending or the next
time input arrives. The PENDIN flag is an internal-state bit. |
| IEXTEN |
Enables extended (implementation-defined) functions to be recognized from the input
data. If this flag is not set, implementation-defined functions are not recognized, and the
corresponding input characters are processed as described for the ICANON, ISIG,
IXON, and IXOFF flags. Recognition of the following special control characters
requires the IEXTEN flag to be set:
- VEOL2
- VDSUSP
- VREPRINT
- VDISCRD
- VWERSE
- VLNEXT
The functions associated with the following bits also require the
IEXTEN flag to be set:
- IMAXBEL
- ECHOKE
- ECHOPRT
- ECHOCTL
|
| TOSTOP |
Sends a SIGTTOU signal when a process in a background process group tries to
write to its controlling terminal. The SIGTTOU signal stops the members of the process
group. |
| ECHO |
Enables echo. If this flag is set, characters are echoed as they are received. |
When the ICANON is set, the following echo functions are
also possible:
| ECHOE |
Echoes the erase character as Backspace-Space-Backspace. If the ECHO and
ECHOE flags are both set and the ECHOPRT flag is not set, the ERASE and WERASE
characters are echoed as one or more ASCII Backspace-Space-Backspace sequences, which clears the
last characters from the screen. |
| ECHOPRT |
If the ECHO and ECHOPRT flags are both set, the first ERASE and WERASE
character in a sequence are echoed as a \ (backslash), followed by the characters being erased.
Subsequent ERASE and WERASE characters echo the characters being erased, in reverse order. The
next non-erase character causes a / (slash) to be typed before the nonerase character is echoed.
This function also requires the IEXTEN bit to be set. |
| ECHOKE |
Backspace-Space-Backspace entire line on line kill. If this flag is set, the kill
character is echoed by erasing the entire line from the screen (using the mechanism selected by
the ECHOE and ECHOPRT flags). This function also requires the IEXTEN flag to
be set. |
| ECHOK |
Echoes the NL character after kill. If the ECHOK flag is set and the
ECHOKE flag is not 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"). |
| ECHOCTL |
Echoes control characters (with codes between 0 and 37 octal) as ^X, where
X is the character that results from adding 100 octal to the code of the control
character. (For example, the character with octal code 1 is echoed as ^A). The ASCII
DEL character (code 177 octal) is echoed as ^?. The ASCII TAB, NL, and START
characters are not echoed. Unless escaped (preceded by a backslash), the EOF character is not
echoed. As a result, because EOT is the default EOF character, terminals that respond to EOT are
prevented from hanging up. This function also requires the IEXTEN flag to be set. |
|
| 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 a 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 and IEXTEN flags are set. EOL2 is an additional line delimiter,
like NL, and is not normally used. |
| VSTART |
Indexes the START special character (Ctrl-q), which is recognized on input if the
IXON flag is set, and generated on output if the IXOFF flag is set. The START
character can be used to resume output that has been suspended by a STOP character. If the
IXON flag is set, the START character is discarded when processed. While output is not
suspended, START characters are ignored and not read. VSTRT is an alias for
VSTART. |
| VSTOP |
Indexes the STOP special character (Ctrl-s), which is recognized on input if the
IXON flag is set, and generated on output if the IXOFF flag is set. The STOP
character can be used to with terminals to prevent output from disappearing before it can be
read. If the IXON flag is set, the STOP character is discarded when processed. While
output is suspended, STOP characters are ignored and not read. |
| VSUSP |
Indexes the SUSP special character (Ctrl-z), which is recognized on input if the
ISIG flag is set. The SUSP character generates a SIGTSTP 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 SUSP character is discarded when processed. |
| VDSUSP |
Indexes the DSUSP special character (Ctrl-y), which is recognized on input if the
ISIG and IEXTEN flags are set. The DSUSP character generates a SIGTSTP
signal as the SUSP character does, but the signal is sent when a process in the foreground
process group attempts to read the DSUSP character, rather than when DSUSP is typed. If the
ISIG and IEXTEN flags are set, the DSUSP character is discarded when processed. |
| VREPRINT |
Indexes the REPRINT special character (Ctrl-r), which is recognized on input if the
ICANON and IEXTEN flags are set. The REPRINT character reprints all characters,
preceded by a new line, that have not been read. If the ICANON and IEXTEN flags are
set, the REPRINT character is discarded when processed. |
| VDISCRD |
Indexes the DISCARD special character (Ctrl-o), which is recognized on input if the
ICANON and IEXTEN flags are set. The DISCARD character causes subsequent output to
be discarded until another DISCARD character is typed, more input arrives, or the condition is
cleared by a program. If the ICANON and IEXTEN flags are set, the DISCARD character
is discarded when processed. |
| VWERSE |
Indexes the WERASE special character (Ctrl-w), which is recognized on input if the
ICANON and IEXTEN flags are set. The WERASE character causes the preceding word to
be erased. The WERASE character does not erase beyond the beginning of the line as delimited by a
NL, EOL, EOF, or EOL2 character. If the ICANON and IEXTEN flags are set, the WERASE
character is discarded when processed. |
| VLNEXT |
Indexes the LNEXT (literal next) special character (Ctrl-v), which is recognized on
input if the ICANON and IEXTEN flags are set. The LNEXT character causes the
special meaning of the next character to be ignored so that characters can be input without being
interpreted by the system. If the ICANON, ECHO, and IEXTEN flags are set,
the LNEXT character is replaced by a ^-Backspace sequence when processed. |
| VMIN |
Indexes the MIN value, which is not a special character. The use of the
MIN value is described in the discussion of noncanonical mode input processing in "ldterm
Line Discipline" in AIX 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 noncanonical mode input processing in "ldterm
Line Discipline"
in AIX General Programming Concepts: Writing and Debugging Programs. |
The character values for the following control characters can be
changed:
| INTR |
EOF |
STOP |
DISCARD |
| QUIT |
EOL |
SUSP |
WERASE |
| ERASE |
EOL2 |
DSUSP |
LNEXT |
| KILL |
START |
REPRINT |
The ERASE, KILL, and EOF characters can also be escaped (preceded
by a backslash) so that no special processing is done. |