The Standard ML Basis Library

The `Posix.TTY` structure

Synopsis

signature POSIX_TTY structure TTY : POSIX_TTY

The structure Posix.TTY specifies a model of a general terminal interface, as described in Section 7 of the POSIX standard 1003.1,1996[CITE].

Interface

eqtype pid eqtype file_desc structure V : sig val eof : int val eol : int val erase : int val intr : int val kill : int val min : int val quit : int val susp : int val time : int val start : int val stop : int val nccs : int type cc val cc : (int * char) list -> cc val update : cc * (int * char) list -> cc val sub : cc * int -> char end structure I : sig include BIT_FLAGS val brkint : flags val icrnl : flags val ignbrk : flags val igncr : flags val ignpar : flags val inlcr : flags val inpck : flags val istrip : flags val ixoff : flags val ixon : flags val parmrk : flags end structure O : sig include BIT_FLAGS val opost : flags end structure C : sig include BIT_FLAGS val clocal : flags val cread : flags val cs5 : flags val cs6 : flags val cs7 : flags val cs8 : flags val csize : flags val cstopb : flags val hupcl : flags val parenb : flags val parodd : flags end structure L : sig include BIT_FLAGS val echo : flags val echoe : flags val echok : flags val echonl : flags val icanon : flags val iexten : flags val isig : flags val noflsh : flags val tostop : flags end eqtype speed val compareSpeed : speed * speed -> order val speedToWord : speed -> SysWord.word val wordToSpeed : SysWord.word -> speed val b0 : speed val b50 : speed val b75 : speed val b110 : speed val b134 : speed val b150 : speed val b200 : speed val b300 : speed val b600 : speed val b1200 : speed val b1800 : speed val b2400 : speed val b4800 : speed val b9600 : speed val b19200 : speed val b38400 : speed type termios val termios : { iflag : I.flags, oflag : O.flags, cflag : C.flags, lflag : L.flags, cc : V.cc, ispeed : speed, ospeed : speed } -> termios val fieldsOf : termios -> { iflag : I.flags, oflag : O.flags, cflag : C.flags, lflag : L.flags, cc : V.cc, ispeed : speed, ospeed : speed } val getiflag : termios -> I.flags val getoflag : termios -> O.flags val getcflag : termios -> C.flags val getlflag : termios -> L.flags val getcc : termios -> V.cc structure CF : sig val getospeed : termios -> speed val getispeed : termios -> speed val setospeed : termios * speed -> termios val setispeed : termios * speed -> termios end structure TC : sig eqtype set_action val sanow : set_action val sadrain : set_action val saflush : set_action eqtype flow_action val ooff : flow_action val oon : flow_action val ioff : flow_action val ion : flow_action eqtype queue_sel val iflush : queue_sel val oflush : queue_sel val ioflush : queue_sel val getattr : file_desc -> termios val setattr : file_desc * set_action * termios -> unit val sendbreak : file_desc * int -> unit val drain : file_desc -> unit val flush : file_desc * queue_sel -> unit val flow : file_desc * flow_action -> unit val getpgrp : file_desc -> pid val setpgrp : file_desc * pid -> unit end

Description

eqtype pid

A process identifier.

eqtype file_desc

An open file descriptor.

structure V

The V substructure provides means for specifying the special control characters.

val eof : int val eol : int val erase : int val intr : int val kill : int val min : int val quit : int val susp : int val time : int val start : int val stop : int

Indices for the special control characters EOF, EOL, ERASE, INTR, KILL, MIN, QUIT, SUSP, TIME, START, and STOP, respectively. These are the indices used in the functions cc and sub.

val nccs : int

The total number of special characters. Thus, valid indices range from 0 to nccs-1.

type cc

A vector of special control characters used by the device driver.

cc l

creates a value of type cc, mapping an index to its paired character. Unspecified indices are associated with #"\000". For example, to have the character #"\^D" (control-D) serve as the EOF (end-of-file) character, one would use

cc [(V.eof, #"\^D")]

to create a cc value, embed this in a termios type, and invoke TC.setattr.

update (cs, l)

returns a copy of cs, but with the new mappings specified by l overwriting the original mappings.

sub (cs, i)

returns the special control character associated in cs with the index i. It raises Subscript if i is negative or i >= nccs.

structure I

The I substructure contains flags for specifying input control. The following table provides a brief description of the flags.

Flag name	Description
`brkint`	Signal interrupt on break.
`icrnl`	Map `CR` (`#"\^M"`) to `NL` (`#"\n"`) on input.
`ignbrk`	Ignore a break condition.
`igncr`	Ignore `CR` characters.
`ignpar`	Ignore characters with parity errors.
`inlcr`	Map `NL` to `CR` on input.
`inpck`	Enable input parity check.
`istrip`	Strip the eighth bit of a byte.
`ixoff`	Enable start/stop input control.
`ixon`	Enable start/stop output control.
`parmrk`	Mark parity errors.

structure O

The O substructure contains flags for specifying output control.

val opost : flags: Perform output processing.

structure C

The C substructure contains flags for specifying basic terminal hardware control. The following table provides a brief description of the flags.

Flag name	Description
`clocal`	Ignore modem status lines.
`cread`	Enable the receiver.
`csize`	Mask for the number of bits per byte used for both transmission and reception. This is the union of `cs5`, `cs6`, `cs7`, and `cs8`.
`cs5`	5 bits per byte.
`cs6`	6 bits per byte.
`cs7`	7 bits per byte.
`cs8`	8 bits per byte.
`cstopb`	Specifies sending two stop bits rather than one.
`hupcl`	Hang up the modem connection when the last process with the port open closes it.
`parenb`	Enable parity generation and detection.
`parodd`	Use odd parity rather than even if `parenb` is set.

structure L

The L substructure contains flags for specifying various local control modes. The following table provides a brief description of the flags.

Flag name	Description
`echo`	Echo input characters back to the terminal.
`echoe`	Echo the `ERASE` character on backspace in canonical mode.
`echok`	Echo the `KILL` character in canonical mode.
`echonl`	In canonical mode, echo a `NL` character even if `echo` is not set.
`icanon`	Set canonical mode, enabling erase and kill processing, and providing line-based input.
`iexten`	Enable extended functions.
`isig`	Enable input characters to be mapped to signals.
`noflsh`	Disable the normal input and output flushing connected with the `INTR`, `QUIT`, and `SUSP` characters. (See the `Posix.TTY.V` substructure.)
`tostop`	Send `Posix.Signal.ttou` for background output.

eqtype speed

Terminal input and output baud rates.

compareSpeed (sp, sp')

returns LESS, EQUAL, or GREATER when the baud rate sp is less than, equal to, or greater than that of sp', respectively.

val speedToWord : speed -> SysWord.word val wordToSpeed : SysWord.word -> speed

These converts between a speed value and its underlying word representation. No checking is performed by wordToSpeed to ensure the resulting value corresponds to an allowed speed in the given system.

type termios

The attributes associated with a terminal. It acts as an abstract representation of the record used as the argument to the termios function.

val termios : { iflag : I.flags, oflag : O.flags, cflag : C.flags, lflag : L.flags, cc : V.cc, ispeed : speed, ospeed : speed } -> termios

This creates a termios value using the given flags, special characters, and speeds.

val fieldsOf : termios -> { iflag : I.flags, oflag : O.flags, cflag : C.flags, lflag : L.flags, cc : V.cc, ispeed : speed, ospeed : speed }

This returns a concrete representation of a termios value.

val getiflag : termios -> I.flags val getoflag : termios -> O.flags val getcflag : termios -> C.flags val getlflag : termios -> L.flags val getcc : termios -> V.cc

These are the obvious projection functions from a termios value to its constituent fields.

structure CF

The CF substructure contains functions for getting and setting the input and output baud rates in a termios value.

val getospeed : termios -> speed val getispeed : termios -> speed: These return the output and input baud rates, respectively, of the argument.

setospeed (t, speed)
setispeed (t, speed): These return a copy of t, but with the output (input) speed set to speed.

structure TC

The TC substructure contains various types and functions used for handling terminal line control.

eqtype set_action

Values of this type specify the behavior of the setattr function.

val sanow : set_action val sadrain : set_action val saflush : set_action

sanow: Changes occur immediately.
sadrain: Changes occur after all output is transmitted.
saflush: Changes occur after all output is transmitted and after all received but unread input is discarded.

eqtype flow_action

Values of this type specify the behavior of the flow function.

val ooff : flow_action val oon : flow_action val ioff : flow_action val ion : flow_action

ooff: Causes suspension of output.
oon: Restarts suspended output.
ioff: Causes the transmission of a STOP character to the terminal device, to stop it from transmitting data.
ion: Causes the transmission of a START character to the terminal device, to restart it transmitting data.

eqtype queue_sel

Values of this type specify the behavior of the flush function.

val iflush : queue_sel val oflush : queue_sel val ioflush : queue_sel

iflush: Causes all data received but not read to be flushed.
oflush: Causes all data written but not transmitted to be flushed.
ioflush: Discards all data written but not transmitted, or received but not read.

getattr fd

gets the attributes of the terminal associated with file descriptor fd.

setattr (fd, action, termios)

sets the attributes of the terminal associated with file descriptor fd as specified in termios. When the change occurs is specified by action.

sendbreak (fd, t)

causes the transmission of a sequence of zero-valued bits to be sent, if the associated terminal is using asynchronous serial data transmission. If t is 0, this will send zero-valued bits for at least a quarter second, and no more than half a second. If t is not zero, zero-valued bits are transmitted for an implementation-defined period of time.

drain fd

waits for all output written on fd to be transmitted.

flush (fd, qs)

discards any data written but not transmitted, or received but not read, depending on the value of qs.

flow (fd, action)

suspends and restarts transmission or reception of data, depending on the value of action.

getpgrp fd

returns the process group ID of the foreground process group associated with the terminal attached to fd.

setpgrp (fd, pid)

sets the foreground process group ID associated with fd to pid.

Discussion

The values of type speed defined in this structure specify the standard baud rates with the obvious correspondence, i.e., b1200 is 1200 baud, b9600 is 9600 baud, etc. The value b0 indicates ``hang up.''

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Generated October 02, 2003
Last Modified July 1, 2002
Comments to John Reppy.

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