man Pages(7):Device and Network Interfaces

wscons(7D)

NAME

wscons- workstation console

SYNOPSIS

#include <sys/strredir.h>

DESCRIPTION

The "workstation console" is a device consisting of the combination of the workstation keyboard and frame buffer, acting in concert to emulate an ASCII terminal. It includes a redirection facility that allows I/O issued to the workstation console to be diverted to some other STREAMS device, so that, for example, window systems can arrange to redirect output that would otherwise appear directly on the frame buffer, corrupting its appearance.

Redirection

The redirection facility maintains a list of devices that have been named as redirection targets, through the SRIOCSREDIR ioctl described below. All entries but the most recent are inactive; when the currently active entry is closed, the most recent remaining entry becomes active. The active entry acts as a proxy for the device being redirected; it handles all read(2), write(2), ioctl(2), and poll(2) calls issued against the redirectee.

The following two ioctls control the redirection facility. In both cases, fd is a descriptor for the device being redirected (that is, the workstation console) and target is a descriptor for a STREAMS device.

SRIOCSREDIR: Make target be the source and destination of I/O ostensibly directed to the device denoted by fd.
SRIOCISREDIR: Returns 1 if target names the device currently acting as proxy for the device denoted by fd, and 0 if it is not.

SPARC ANSI Standard Terminal Emulation

On SPARC based systems, the PROM monitor emulates an ANSI X3.64 terminal.

Note: the VT100 also follows the ANSI X3.64 standard but both the Sun and the VT100 have nonstandard extensions to the ANSI X3.64 standard. The Sun terminal emulator and the VT100 are not compatible in any true sense.

The Sun console displays 34 lines of 80 ASCII characters per line, with scrolling, (x, y) cursor addressability, and a number of other control functions.

While the display size is usually 34 by 80, there are instances where it may be a different size.

If the display device is not large enough to display 34 lines of text.
On SPARC based systems, if either screen-#rows or screen-#columns is set by the user to a value other than the default of 34 or 80 respectively. screen-#rows and screen-#columns are fields stored in NVRAM/EEPROM, see eeprom(1M).

The Sun console displays a cursor which marks the current line and character position on the screen. ASCII characters between 0x20 (space) and 0x7E (tilde) inclusive are printing characters -- when one is written to the Sun console (and is not part of an escape sequence), it is displayed at the current cursor position and the cursor moves one position to the right on the current line.

On SPARC based systems, later PROM revisions have the full 8-bit ISO Latin-1 (ISO 8859-1) character set, not just ASCII. Earlier PROM revisions display characters in the range 0xA0 - 0xFE as spaces.

If the cursor is already at the right edge of the screen, it moves to the first character position on the next line. If the cursor is already at the right edge of the screen on the bottom line, the Line-feed function is performed (see CTRL-J below), which scrolls the screen up by one or more lines or wraps around, before moving the cursor to the first character position on the next line.

SPARC Control Sequence Syntax

The Sun console defines a number of control sequences which may occur in its input. When such a sequence is written to the Sun console, it is not displayed on the screen, but effects some control function as described below, for example, moves the cursor or sets a display mode.

Some of the control sequences consist of a single character. The notation

CTRL-X

for some character X, represents a control character.

Other ANSI control sequences are of the form

ESC [ params char

Spaces are included only for readability; these characters must occur in the given sequence without the intervening spaces.

ESC: represents the ASCII escape character (ESC, CTRL-[, 0x1B).
[: The next character is a left square bracket `[' (0x5B).
params: are a sequence of zero or more decimal numbers made up of digits between 0 and 9, separated by semicolons.
char: represents a function character, which is different for each control sequence.

Some examples of syntactically valid escape sequences are (again, ESC represent the single ASCII character `Escape'):

ESC[m	select graphic rendition with default parameter
ESC[7m	select graphic rendition with reverse image
ESC[33;54H	set cursor position
ESC[123;456;0;;3;B	move cursor down

Syntactically valid ANSI escape sequences which are not currently interpreted by the Sun console are ignored. Control characters which are not currently interpreted by the Sun console are also ignored.

Each control function requires a specified number of parameters, as noted below. If fewer parameters are supplied, the remaining parameters default to 1, except as noted in the descriptions below.

If more than the required number of parameters is supplied, only the last n are used, where n is the number required by that particular command character. Also, parameters which are omitted or set to zero are reset to the default value of 1 (except as noted below).

Consider, for example, the command character M which requires one parameter. ESC[;M and ESC[0M and ESC[M and ESC[23;15;32;1M are all equivalent to ESC[1M and provide a parameter value of 1. Note: ESC[;5M (interpreted as `ESC[5M') is not equivalent to ESC[5;M (interpreted as `ESC[5;1M') which is ultimately interpreted as `ESC[1M').

In the syntax descriptions below, parameters are represented as `#' or `#1;#2'.

SPARC ANSI Control Functions

The following paragraphs specify the ANSI control functions implemented by the Sun console. Each description gives:

the control sequence syntax
the hex equivalent of control characters where applicable
the control function name and ANSI or Sun abbreviation (if any).
description of parameters required, if any
description of the control function
for functions which set a mode, the initial setting of the mode. The initial settings can be restored with the SUNRESET escape sequence.

SPARC Control Character Functions

CTRL-G (0x7)Bell (BEL)

The Sun Workstation Model 100 and 100U is not equipped with an audible bell. It `rings the bell' by flashing the entire screen. The window system flashes the window. The screen will also be flashed on current models if the Sun keyboard is not the console input device.

CTRL-H (0x8)Backspace (BS)

The cursor moves one position to the left on the current line. If it is already at the left edge of the screen, nothing happens.

CTRL-I (0x9)Tab (TAB)

The cursor moves right on the current line to the next tab stop. The tab stops are fixed at every multiple of 8 columns. If the cursor is already at the right edge of the screen, nothing happens; otherwise the cursor moves right a minimum of one and a maximum of eight character positions.

CTRL-J (0xA)Line-feed (LF)

The cursor moves down one line, remaining at the same character position on the line. If the cursor is already at the bottom line, the screen either scrolls up or ``wraps around'' depending on the setting of an internal variable S (initially 1) which can be changed by the ESC[r control sequence. If S is greater than zero, the entire screen (including the cursor) is scrolled up by S lines before executing the line-feed. The top S lines scroll off the screen and are lost. S new blank lines scroll onto the bottom of the screen. After scrolling, the line-feed is executed by moving the cursor down one line.

If S is zero, `wrap-around' mode is entered. `ESC [ 1 r' exits back to scroll mode. If a line-feed occurs on the bottom line in wrap mode, the cursor goes to the same character position in the top line of the screen. When any line-feed occurs, the line that the cursor moves to is cleared. This means that no scrolling occurs. Wrap-around mode is not implemented in the window system.

On SPARC based systems, the screen scrolls as fast as possible depending on how much data is backed up waiting to be printed. Whenever a scroll must take place and the console is in normal scroll mode (`ESC [ 1 r'), it scans the rest of the data awaiting printing to see how many line-feeds occur in it. This scan stops when any control character from the set {VT, FF, SO, SI, DLE, DC1, DC2, DC3, DC4, NAK, SYN, ETB, CAN, EM, SUB, ESC, FS, GS, RS, US} is found. At that point, the screen is scrolled by N lines (N >= 1) and processing continues. The scanned text is still processed normally to fill in the newly created lines. This results in much faster scrolling with scrolling as long as no escape codes or other control characters are intermixed with the text.

See also the discussion of the `Set scrolling' (ESC[r) control function below.

CTRL-K (0xB)Reverse Line-feed

The cursor moves up one line, remaining at the same character position on the line. If the cursor is already at the top line, nothing happens.

CTRL-L (0xC)Form-feed (FF)

The cursor is positioned to the Home position (upper-left corner) and the entire screen is cleared.

CTRL-M (0xD)Return (CR)

The cursor moves to the leftmost character position on the current line.

SPARC Escape Sequence Functions

CTRL-[ (0x1B) Escape (ESC)

This is the escape character. Escape initiates a multi-character control sequence.

ESC[#@ Insert Character (ICH)

Takes one parameter, # (default 1). Inserts # spaces at the current cursor position. The tail of the current line starting at the current cursor position inclusive is shifted to the right by # character positions to make room for the spaces. The rightmost # character positions shift off the line and are lost. The position of the cursor is unchanged.

ESC[#A Cursor Up (CUU)

Takes one parameter, # (default 1). Moves the cursor up # lines. If the cursor is fewer than # lines from the top of the screen, moves the cursor to the topmost line on the screen. The character position of the cursor on the line is unchanged.

ESC[#B Cursor Down (CUD)

Takes one parameter, # (default 1). Moves the cursor down # lines. If the cursor is fewer than # lines from the bottom of the screen, move the cursor to the last line on the screen. The character position of the cursor on the line is unchanged.

ESC[#C Cursor Forward (CUF)

Takes one parameter, # (default 1). Moves the cursor to the right by # character positions on the current line. If the cursor is fewer than # positions from the right edge of the screen, moves the cursor to the rightmost position on the current line.

ESC[#D Cursor Backward (CUB)

Takes one parameter, # (default 1). Moves the cursor to the left by # character positions on the current line. If the cursor is fewer than # positions from the left edge of the screen, moves the cursor to the leftmost position on the current line.

ESC[#E Cursor Next Line (CNL)

Takes one parameter, # (default 1). Positions the cursor at the leftmost character position on the #-th line below the current line. If the current line is less than # lines from the bottom of the screen, positions the cursor at the leftmost character position on the bottom line.

ESC[#1;#2f Horizontal And Vertical Position (HVP)

ESC[#1;#2H Cursor Position (CUP)

Takes two parameters, #1 and #2 (default 1, 1). Moves the cursor to the #2-th character position on the #1-th line. Character positions are numbered from 1 at the left edge of the screen; line positions are numbered from 1 at the top of the screen. Hence, if both parameters are omitted, the default action moves the cursor to the home position (upper left corner). If only one parameter is supplied, the cursor moves to column 1 of the specified line.

ESC[J Erase in Display (ED)

Takes no parameters. Erases from the current cursor position inclusive to the end of the screen. In other words, erases from the current cursor position inclusive to the end of the current line and all lines below the current line. The cursor position is unchanged.

ESC[K Erase in Line (EL)

Takes no parameters. Erases from the current cursor position inclusive to the end of the current line. The cursor position is unchanged.

ESC[#L Insert Line (IL)

Takes one parameter, # (default 1). Makes room for # new lines starting at the current line by scrolling down by # lines the portion of the screen from the current line inclusive to the bottom. The # new lines at the cursor are filled with spaces; the bottom # lines shift off the bottom of the screen and are lost. The position of the cursor on the screen is unchanged.

ESC[#M Delete Line (DL)

Takes one parameter, # (default 1). Deletes # lines beginning with the current line. The portion of the screen from the current line inclusive to the bottom is scrolled upward by # lines. The # new lines scrolling onto the bottom of the screen are filled with spaces; the # old lines beginning at the cursor line are deleted. The position of the cursor on the screen is unchanged.

ESC[#P Delete Character (DCH)

Takes one parameter, # (default 1). Deletes # characters starting with the current cursor position. Shifts to the left by # character positions the tail of the current line from the current cursor position inclusive to the end of the line. Blanks are shifted into the rightmost # character positions. The position of the cursor on the screen is unchanged.

ESC[#m Select Graphic Rendition (SGR)

Takes one parameter, # (default 0). Note: unlike most escape sequences, the parameter defaults to zero if omitted. Invokes the graphic rendition specified by the parameter. All following printing characters in the data stream are rendered according to the parameter until the next occurrence of this escape sequence in the data stream. Currently only two graphic renditions are defined:

0: Normal rendition.
7: Negative (reverse) image.

Negative image displays characters as white-on-black if the screen mode is currently black-on white, and vice-versa. Any non-zero value of # is currently equivalent to 7 and selects the negative image rendition.

ESC[p Black On White (SUNBOW)

Takes no parameters. Sets the screen mode to black-on-white. If the screen mode is already black-on-white, has no effect. In this mode spaces display as solid white, other characters as black-on-white. The cursor is a solid black block. Characters displayed in negative image rendition (see `Select Graphic Rendition' above) is white-on-black in this mode. This is the initial setting of the screen mode on reset.

ESC[q White On Black (SUNWOB)

Takes no parameters. Sets the screen mode to white-on-black. If the screen mode is already white-on-black, has no effect. In this mode spaces display as solid black, other characters as white-on-black. The cursor is a solid white block. Characters displayed in negative image rendition (see `Select Graphic Rendition' above) is black-on-white in this mode. The initial setting of the screen mode on reset is the alternative mode, black on white.

ESC[#r Set scrolling (SUNSCRL)

Takes one parameter, # (default 0). Sets to # an internal register which determines how many lines the screen scrolls up when a line-feed function is performed with the cursor on the bottom line. A parameter of 2 or 3 introduces a small amount of ``jump'' when a scroll occurs. A parameter of 34 clears the screen rather than scrolling. The initial setting is 1 on reset.

A parameter of zero initiates ``wrap mode'' instead of scrolling. In wrap mode, if a linefeed occurs on the bottom line, the cursor goes to the same character position in the top line of the screen. When any linefeed occurs, the line that the cursor moves to is cleared. This means that no scrolling ever occurs. `ESC [ 1 r' exits back to scroll mode.

For more information, see the description of the Line-feed (CTRL-J) control function above.

ESC[s Reset terminal emulator (SUNRESET)

Takes no parameters. Resets all modes to default, restores current font from PROM. Screen and cursor position are unchanged.

RETURN VALUES

When there are no errors, the redirection ioctls have return values as described above. Otherwise, they return -1 and set errno to indicate the error.

If the target stream is in an error state, errno is set accordingly.

ERRORS

EBADF: target does not denote an open file.
ENOSTR: target does not denote a STREAMS device.
EINVAL: (x86 only) fd does not denote /dev/console.

FILES

/dev/wscons: the workstation console, accessed by way of the redirection facility

x86 Only

/dev/systty
/dev/syscon
/dev/console: the device that must be opened for the SRIOCSREDIR and SRIOCISREDIR ioctls

WARNINGS

The redirection ioctls block while there is I/O outstanding on the device instance being redirected. Thus, attempting to redirect the workstation console while there is a read outstanding on it will hang until the read completes.

NOTES

On Sun Enterprise 10000 servers the netcon facility supersedes wscons(7D). wscons is useful for systems that do have directly attached consoles, such as frame buffers and keyboards, but it is not useful with the Enterprise 10000 server, which does not. For more information, refer to netcon(1M) in the Sun Enterprise 10000 SSP Reference Manual or cvcd(1M).

SunOS 5.7 Last Revised 27 Jan 1998