termios.4

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 4 代码 · 共 1,622 行 · 第 1/4 页

changed.
.IP "\fBEOL\fR" 
Special character on input that is recognized if the ICANON flag
is set.  It is an additional line delimiter, like NL.  The default
value is POSIX_V_DISABLE, which is used to specify that this special
character is ordinarily not used.
.IP "\fBSUSP\fR" 
Special character on input that is recognized if the ISIG flag is
enabled.  Generates a SIGTSTP signal
that is sent to all processes in the foreground process group
associated with the terminal.  This signal is used by the
job control code to change from the current job to the
controlling job.  
If ISIG is set, the SUSP character is discarded when processed.
The default value is CTRL/Z (ASCII SUB).
.IP "\fBSTOP\fR" 
Special character on both input and output that is recognized if
the IXON (input) or IXOFF (output) flag is set.
Can be used to temporarily suspend output.  It is useful with CRT
terminals to prevent output from disappearing before it can be
read.  While output is suspended, STOP characters are ignored and
not read.  
If IXON is set, the STOP character is discarded when processed.
The default value is CTRL/S (ASCII DC3).
.IP "\fBSTART\fR" 
Special character on both input and output that is recognized if 
the IXON (input) or IXOFF (output) flag is set.  Can
be used to resume output that has been suspended by a STOP 
character.  While output is not suspended, START characters are
ignored and not read.  
If IXON is set, the STOP character is discarded when processed.
The default value is CTRL/Q (ASCII DC1).
.IP "\fBCR\fR" 
Special character on input that is recognized if the ICANON flag is
set.  The value is (\\r) and this value is not changeable.
When ICANON and ICRNL are set and 
IGNCR is not set, this character is translated into an NL,
and it has the same effect as an NL character.
.IP "\fBDSUSP\fR" 
Special character on input used as a delayed suspend character.
DSUSP is only recognized if the IEXTEN flag is set.
Similar to the SUSP special character, a SIGTSTP signal is
issued.  The process cannot actually stop until the
next character is input.  
If IEXTEN is set, the DSUSP character is discarded when processed.
The default value is CTRL/Y (ASCII
EM).
.IP "\fBRPRNT\fR" 
Special character on input used to force the present input line
to be re-echoed to the terminal after a newline character.  
RPRNT is only recognized if the IEXTEN flag is set.
If IEXTEN is set, the RPRNT character is discarded when processed.
The default value is CTRL/R (ASCII DC2).
.IP "\fBFLUSH\fR" 
Special character on input that causes output to the terminal
to be flushed until another flush character is typed or more input
is received on the terminal.  
FLUSH is recognized only if the IEXTEN flag is set.
If IEXTEN is set, the FLUSH character is discarded when processed.
The default value is CTRL/O 
(ASCII SI).
.IP "\fBWERASE\fR" 
Special character on input used to erase the preceding word
of the input queue.  The word erase operation erases 
characters up to (and not including) a TAB, NL, space, or backslash
(\\) character.  Word erase cannot erase beyond the start of a
line as delimited by NL, EOF, or EOL. 
WERASE is only recognized if the IEXTEN flag is set.
If IEXTEN is set, the WERASE character is discarded when processed.
The default value is
CTRL/W (ASCII ETB).
.IP "\fBLNEXT\fR" 
Special character on input used to disassociate any special
meaning that the next input character has.  This allows for
the input of characters that would otherwise be interpreted as
special characters. 
LNEXT is only recognized if the IEXTEN flag is set.
If IEXTEN is set, the LNEXT character is discarded when processed.
The default value is CTRL/V (ASCII SYN).
.IP "\fBQUOTE\fR" 
Special character on input used to enter a literal ERASE or
KILL character.  The same functionality could be achieved through
the use of the LNEXT character, but QUOTE is included for
backward compatibility.  The default value is a backslash (\\).
QUOTE is only recognized if the IEXTEN flag is set.
If IEXTEN is set, the QUOTE character is discarded when processed.
.PP
The values for INTR, QUIT, ERASE, KILL, EOF, EOL, SUSP, START, STOP, 
DSUSP, RPRNT, FLUSH
WERASE, LNEXT, and QUOTE 
are changeable to suit individual tastes.
The following special characters are local extensions of DSUSP, RPRNT, FLUSH,
WERASE, LNEXT, and QUOTE.
.PP
Special character functions can be disabled individually by setting them to
the constant POSIX_V_DISABLE, which is defined to be zero.
The POSIX_V_DISABLE character is always read if received, and never causes a 
special character function.  With the exception of NL and EOL, the special
characters cannot be passed up to the reading process.
.PP
If two or more special characters have the same value, the function performed
when that character is received is undefined.  More than one special
character can be set to POSIX_V_DISABLE to disable the control function
normally associated with the special character.
.SH Settable Parameters
Routines that need to control certain terminal I/O characteristics can  do so
by using the termios structure as defined in the header 
.PN <termios.h> .  
The members of this structure include:
.EX
        Member       Member     Description
        Type         Name

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   */
	cc_t         c_cc[NCCS] /* control chars */
	cc_t         c_line;    /* line discipline */
}
.EE
.PP
The types tcflag_t and cc_t are defined in the header 
.PN <termios.h> .
.PP
.B Input Modes
.PP
The c_iflag field describes the basic terminal input control:
.PP
.TS
tab(@);
lw(1i) lw(2i).
_
.sp 6p
.HB
Mask Name@Description
.R
.sp 6p
_
.sp 6p
IGNBRK@T{
Ignore the break condition.
T}
BRKINT@T{
Signal interrupt on break.
T}
IGNPAR@T{
Ignore characters with parity errors.
T}
PARMRK@T{
Mark parity errors.
T}
INPCK@T{
Enable input parity check.
T}
ISTRIP@Strip character.
INLCR@T{
Map NL to CR on input.
T}
IGNCR@Ignore CR.
ICRNL@T{
Map CR to NL on input.
T}
IXON@T{
Enable start/stop output control.
T}
IXOFF@T{
Enable start/stop input control.
T}
.sp 6p
_
.TE
.PP
A break condition is defined as a sequence of zero-valued bits that 
continues for more than the time to send one byte.  The entire sequence
of zero-valued bits is interpreted as a single break condition, even if
it continues for a time equivalent to more than one byte.
.PP
If IGNBRK is set, a break condition 
detected on input is ignored, that is, not put on the input queue and
therefore not read by any process.  Otherwise, if BRKINT is set, the break
condition generates a single SIGINT signal and flushes both the input and 
output queues.  If neither IGNBRK or BRKINT is set, a break condition is read
as a single \\0 (ASCII NUL), or, if PARMRK is set, as \\377,\\0,\\0.
.PP
If IGNPAR is set, a byte with a framing or parity error (other than break) is
ignored.
.PP
If PARMRK is set and IGNPAR is not set, 
a character with a framing or parity error (other than break)
that is not ignored is given to the application as the 3-character 
sequence \\377,\\0,X, where \\377, \\0 is a 2-character 
flag preceding each 
sequence and X is the data of the character received in error.  To avoid 
ambiguity in this case, if ISTRIP is not set, a valid character of \\377 is
given to the application as \\377, \\377.  If either IGNPAR or 
PARMRK is set, a framing
or parity error (other than break) that is not ignored is given to the 
application as a single character \\0.
.PP
If INPCK is set, input parity checking is enabled.  If INPCK is not set, input
parity checking is disabled, allowing output parity generation without input
parity errors.  Parity checking can be enabled, even if
parity checking is not enabled.    If parity detection is enabled, but 
input parity checking is disabled, the hardware that
connects to the terminal recognizes the parity bit, but the terminal
special file does not check whether this bit is set correctly or not.
.PP
If ISTRIP is set, valid input characters are first stripped to seven bits; 
otherwise, all eight bits are processed.
.PP
If INLCR is set, a received NL character is translated into a CR character.  If
IGNCR is set, a received CR character is ignored (not read).  
If IGNCR is not set and
ICRNL is set, a received CR character is translated into a NL character.
.PP
If IXON is set, start/stop output control is enabled.  A received STOP 
character suspends output and a received START character restarts output.  When
IXON is set, START and STOP characters are not read, but merely perform flow
control functions.  When IXON is not set, the START and STOP characters 
are read.
.PP
If IXOFF is set, start/stop input control is enabled.  The system transmits
STOP characters which cause the terminal device to stop
transmitting data when the number of characters in the input
queue attempt to exceed MAX_INPUT (256).  As soon as the device can 
continue transmitting data without risk of an overflow, START characters are 
transmitted which cause the terminal device to resume transmitting data.
.PP
The initial input control value after 
.MS open 2
is 0 (all settings off).
.PP
.B Output Modes
.PP
The c_oflag field specifies the terminal interface's treatment of output.
Because OPOST is the only output flag defined by the POSIX standard, all of
the other definitions are local extensions to the standard.  
.PP
.TS
tab(@);
lw(1i) lw(2i).
_
.sp 6p
.HB
Mask Name@Description
.R
.sp 6p
_
.sp 6p
OPOST@Postprocess output.
OLCUC@T{
Map lower case to upper on output.
T}
ONLCR@T{
Map NL to CR-NL on output.
T}
OCRNL@T{
Map CR to NL on output.
T}
ONOCR@T{
No CR output at column 0.
T}
ONLRET@T{
NL performs CR function.
T}
OFILL@T{
Use fill characters for delay.
T}
OFDEL@T{
Fill is DEL, else NUL.
T}

NLDLY@T{
Select new-line delays:
T}
NL0@T{
New-line delay type 0.
T}
NL1@T{
New-line delay type 1.
T}

CRDLY@T{
Select carriage-return delays:
T}
CR0@T{
Carriage-return delay type 0.
T}
CR1@T{
Carriage-return delay type 1.
T}
CR2@T{
Carriage-return delay type 2.
T}
CR3@T{
Carriage-return delay type 3.
T}

TABDLY@T{
Select horizontal-tab delays:
T}
TAB0@T{
Horizontal-tab delay type 0.
T}
TAB1@T{
Horizontal-tab delay type 1.
T}
TAB2@T{
Horizontal-tab delay type 2.
T}
TAB3@T{
Expand tabs to spaces.
T}

BSDLY@T{
Select backspace delays:
T}
BS0@T{
Backspace delay type 0.
T}
BS1@T{
Backspace delay type 1.
T}

VTDLY@T{
Select vertical-tab delays:
T}
VT0@T{
Vertical-tab delay type 0.
T}
VT1@T{
Vertical-tab delay type 1.
T}

FFDLY@T{
Select form-feed delays:
T}
FF0@T{
Form-feed delay type 0.
T}
FF1@T{
Form-feed delay type 1.
T}
.sp 6p
_
.TE
.PP
If OPOST is set, output characters are post-processed as
indicated by the remaining flags. Otherwise, characters are
transmitted without change.
.PP
If OLCUC is set, a lowercase letter is
transmitted as the corresponding uppercase letter.  This
function is often used in conjunction with IUCLC.
.PP
If ONLCR is set, the NL character is transmitted as the CR-NL
character pair.  If OCRNL is set, the CR character is
transmitted as the NL character.  If ONOCR is set, no CR
character is transmitted when at column 0 (first position).
If ONLRET is set, the NL character is assumed to do the
carriage-return function; the column pointer is set to
0, and the delays specified for CR are used.  Otherwise
the NL character is assumed to do just the line-feed function;
the column pointer remains unchanged.  The column
pointer is also set to 0 if the CR character is actually
transmitted.
.PP
Delay bits specify transmission stops that allow mechanical or 
other movement when certain characters are
sent to the terminal.  In all cases, a value of 0 indicates
no delay.  If OFILL is set, fill characters are 
transmitted for delay instead of a timed delay.  This is
useful for high baud rate terminals which need only a
minimal delay.  If OFDEL is set, the fill character is DEL.
Otherwise, it is NUL.
.PP
The delay specifications for NLDLY, CRDLY, TABDLY, BSDLY, VTDLY and
FFDLY are meant to serve as masks for the respective delay field.
.PP
If a form-feed or vertical-tab delay is specified, either delay lasts
approximately two seconds.
.PP
New-line delay lasts about 0.10 seconds.  If ONLRET is set,
the carriage-return delays are used instead of the new-line
delays.  If OFILL is set, two fill characters are transmitted.
.PP
Carriage-return delay for type 1 depends on the current
column position, type 2 is approximately 0.10 seconds, and type 3 is
approximately 0.15 seconds.  If OFILL is set, delay type 1 transmits
two fill characters, and type 2, four fill characters.
.PP
Horizontal-tab delay type 1 depends on the current
column position.  Type 2 is approximately 0.10 seconds.  Type 3
specifies that tabs are to be expanded into spaces.  If
OFILL is set, two fill characters are transmitted for
any delay.
.PP
Backspace delay lasts about 0.05 seconds.  If OFILL is set,
one fill character is transmitted.
.PP
The actual delays depend on line speed and system load.
.PP
The initial output control value after open(2) is 0 (all settings off).
.PP