TERMINFO

For more on terminal naming conventions, see the term(7) manual page.

Capabilities
The following is a complete table of the capabilities included in a terminfo description block and available to terminfo-using code. In each line of the table,

The variable is the name by which the programmer (at the terminfo level) accesses the capability.

The capname is the short name used in the text of the database, and is used by a person updating the database. Whenever possible, capnames are chosen to be the same as or similar to the ANSI X3.64-1979 standard (now superseded by ECMA-48, which uses identical or very similar names). Semantics are also intended to match those of the specification.

The termcap code is the old termcap capability name (some capabilities are new, and have names which termcap did not originate).

Capability names have no hard length limit, but an informal limit of 5 characters has been adopted to keep them short and to allow the tabs in the source file Caps to line up nicely.

Finally, the description field attempts to convey the semantics of the capability. You may find some codes in the description field:

These are the boolean capabilities:

These are the numeric capabilities:

The following numeric capabilities are present in the SVr4.0 term structure, but are not yet documented in the man page. They came in with SVr4’s printer support.

These are the string capabilities:

The following string capabilities are present in the SVr4.0 term structure, but are not documented in the man page.

The XSI Curses standard added these. They are probably in some post-4.1 version of System V curses as well, but because XSI Curses lists them in strict alphabetical order we don’t know if this is the right binary order. The ncurses termcap names for them are invented; according to the XSI Curses standard, they have no termcap names. If your compiled terminfo entries use these, they may not be binary-compatible with System V terminfo entries after SVr4.1; beware!

A Sample Entry
The following entry, describing an ANSI-standard terminal, is representative of what a terminfo entry for a modern terminal typically looks like.

ansi|ansi/pc-term compatible with color,
mc5i,
colors#8, ncv#3, pairs#64,
cub=\E[%p1%dD, cud=\E[%p1%dB, cuf=\E[%p1%dC,
cuu=\E[%p1%dA, dch=\E[%p1%dP, dl=\E[%p1%dM,
ech=\E[%p1%dX, el1=\E[1K, hpa=\E[%p1%dG, ht=\E[I,
ich=\E[%p1%d@, il=\E[%p1%dL, indn=\E[%p1%dS,
kbs=^H, kcbt=\E[Z, kcub1=\E[D, kcud1=\E[B,
kcuf1=\E[C, kcuu1=\E[A, kf1=\E[M, kf10=\E[V,
kf11=\E[W, kf12=\E[X, kf2=\E[N, kf3=\E[O, kf4=\E[P,
kf5=\E[Q, kf6=\E[R, kf7=\E[S, kf8=\E[T, kf9=\E[U,
kich1=\E[L, mc4=\E[4i, mc5=\E[5i, nel=\r\E[S,
op=\E[37;40m, rep=%p1%c\E[%p2%{1}%-%db,
rin=\E[%p1%dT, s0ds=\E(B, s1ds=\E)B, s2ds=\E*B,
s3ds=\E+B, setab=\E[4%p1%dm, setaf=\E[3%p1%dm,
setb=\E[4%?%p1%{1}%=%t4%e%p1%{3}%=%t6%e%p1%{4}%=%t1%e%p1%{6}%=%t3%e%p1%d%;m,
setf=\E[3%?%p1%{1}%=%t4%e%p1%{3}%=%t6%e%p1%{4}%=%t1%e%p1%{6}%=%t3%e%p1%d%;m,
sgr=\E[0;10%?%p1%t;7%;%?%p2%t;4%;%?%p3%t;7%;%?%p4%t;5%;%?%p6%t;1%;%?%p7%t;8%;%?%p8%t;11%;%?%p9%t;12%;m,
sgr0=\E[0;10m, tbc=\E[2g, u6=\E[%d;%dR, u7=\E[6n,
u8=\E[?%[;0123456789]c, u9=\E[c, vpa=\E[%p1%dd,

Entries may continue onto multiple lines by placing white space at the beginning of each line except the first. Comments may be included on lines beginning with ’’#’’. Capabilities in terminfo are of three types: Boolean capabilities which indicate that the terminal has some particular feature, numeric capabilities giving the size of the terminal or the size of particular delays, and string capabilities, which give a sequence which can be used to perform particular terminal operations.

Types of Capabilities
All capabilities have names. For instance, the fact that ANSI-standard terminals have automatic margins (i.e., an automatic return and line-feed when the end of a line is reached) is indicated by the capability am. Hence the description of ansi includes am. Numeric capabilities are followed by the character ’#’ and then the value. Thus cols, which indicates the number of columns the terminal has, gives the value ’80’ for ansi.

Finally, string valued capabilities, such as el (clear to end of line sequence) are given by the two-character code, an ’=’, and then a string ending at the next following ’,’.

A number of escape sequences are provided in the string valued capabilities for easy encoding of characters there. Both \E and \e map to an ESCAPE character, ^x maps to a control-x for any appropriate x, and the sequences \n \l \r \t \b \f \s give a newline, line-feed, return, tab, backspace, form-feed, and space. Other escapes include \^ for ^, \\ for \, \, for comma, \: for :, and \0 for null. (\0 will produce \200, which does not terminate a string but behaves as a null character on most terminals.) Finally, characters may be given as three octal digits after a \.

A delay in milliseconds may appear anywhere in a string capability, enclosed in $<..> brackets, as in el=\EK$<5>, and padding characters are supplied by tputs to provide this delay. The delay must be a number with at most one decimal place of precision; it may be followed by suffixes ’*’ or ’/’ or both. A ’*’ indicates that the padding required is proportional to the number of lines affected by the operation, and the amount given is the per-affected-unit padding required. (In the case of insert character, the factor is still the number of lines affected.) Normally, padding is advisory if the device has the xon capability; it is used for cost computation but does not trigger delays. A ’/’ suffix indicates that the padding is mandatory and forces a delay of the given number of milliseconds even on devices for which xon is present to indicate flow control.

Sometimes individual capabilities must be commented out. To do this, put a period before the capability name. For example, see the second ind in the example above.

Fetching Compiled Descriptions
If the environment variable TERMINFO is set, it is interpreted as the pathname of a directory containing the compiled description you are working on. Only that directory is searched.

If TERMINFO is not set, the ncurses version of the terminfo reader code will instead look in the directory $HOME/.terminfo for a compiled description. If it fails to find one there, and the environment variable TERMINFO_DIRS is set, it will interpret the contents of that variable as a list of colon- separated directories to be searched (an empty entry is interpreted as a command to search /usr/share/terminfo). If no description is found in any of the TERMINFO_DIRS directories, the fetch fails.

If neither TERMINFO nor TERMINFO_DIRS is set, the last place tried will be the system terminfo directory, /usr/share/terminfo.

(Neither the $HOME/.terminfo lookups nor TERMINFO_DIRS extensions are supported under stock System V terminfo/curses.)

Preparing Descriptions
We now outline how to prepare descriptions of terminals. The most effective way to prepare a terminal description is by imitating the description of a similar terminal in terminfo and to build up a description gradually, using partial descriptions with vi or some other screen-oriented program to check that they are correct. Be aware that a very unusual terminal may expose deficiencies in the ability of the terminfo file to describe it or bugs in the screen-handling code of the test program.

To get the padding for insert line right (if the terminal manufacturer did not document it) a severe test is to edit /etc/passwd at 9600 baud, delete 16 or so lines from the middle of the screen, then hit the ’u’ key several times quickly. If the terminal messes up, more padding is usually needed. A similar test can be used for insert character.

Basic Capabilities
The number of columns on each line for the terminal is given by the cols numeric capability. If the terminal is a CRT , then the number of lines on the screen is given by the lines capability. If the terminal wraps around to the beginning of the next line when it reaches the right margin, then it should have the am capability. If the terminal can clear its screen, leaving the cursor in the home position, then this is given by the clear string capability. If the terminal overstrikes (rather than clearing a position when a character is struck over) then it should have the os capability. If the terminal is a printing terminal, with no soft copy unit, give it both hc and os. (os applies to storage scope terminals, such as TEKTRONIX 4010 series, as well as hard copy and APL terminals.) If there is a code to move the cursor to the left edge of the current row, give this as cr. (Normally this will be carriage return, control M.) If there is a code to produce an audible signal (bell, beep, etc) give this as bel.

If there is a code to move the cursor one position to the left (such as backspace) that capability should be given as cub1. Similarly, codes to move to the right, up, and down should be given as cuf1, cuu1, and cud1. These local cursor motions should not alter the text they pass over, for example, you would not normally use ’cuf1= ’ because the space would erase the character moved over.

A very important point here is that the local cursor motions encoded in terminfo are undefined at the left and top edges of a CRT terminal. Programs should never attempt to backspace around the left edge, unless bw is given, and never attempt to go up locally off the top. In order to scroll text up, a program will go to the bottom left corner of the screen and send the ind (index) string.

To scroll text down, a program goes to the top left corner of the screen and sends the ri (reverse index) string. The strings ind and ri are undefined when not on their respective corners of the screen.

Parameterized versions of the scrolling sequences are indn and rin which have the same semantics as ind and ri except that they take one parameter, and scroll that many lines. They are also undefined except at the appropriate edge of the screen.

The am capability tells whether the cursor sticks at the right edge of the screen when text is output, but this does not necessarily apply to a cuf1 from the last column. The only local motion which is defined from the left edge is if bw is given, then a cub1 from the left edge will move to the right edge of the previous row. If bw is not given, the effect is undefined. This is useful for drawing a box around the edge of the screen, for example. If the terminal has switch selectable automatic margins, the terminfo file usually assumes that this is on; i.e., am. If the terminal has a command which moves to the first column of the next line, that command can be given as nel (newline). It does not matter if the command clears the remainder of the current line, so if the terminal has no cr and lf it may still be possible to craft a working nel out of one or both of them.

These capabilities suffice to describe hard-copy and “glass-tty” terminals. Thus the model 33 teletype is described as

while the Lear Siegler ADM-3 is described as

Parameterized Strings
Cursor addressing and other strings requiring parameters in the terminal are described by a parameterized string capability, with printf(3S) like escapes %x in it. For example, to address the cursor, the cup capability is given, using two parameters: the row and column to address to. (Rows and columns are numbered from zero and refer to the physical screen visible to the user, not to any unseen memory.) If the terminal has memory relative cursor addressing, that can be indicated by mrcup.

The parameter mechanism uses a stack and special % codes to manipulate it. Typically a sequence will push one of the parameters onto the stack and then print it in some format. Often more complex operations are necessary.

The % encodings have the following meanings:

Binary operations are in postfix form with the operands in the usual order. That is, to get x-5 one would use "%gx%{5}%-". %P and %g variables are persistent across escape-string evaluations.

Consider the HP2645, which, to get to row 3 and column 12, needs to be sent \E&a12c03Y padded for 6 milliseconds. Note that the order of the rows and columns is inverted here, and that the row and column are printed as two digits. Thus its cup capability is “cup=6\E&%p2%2dc%p1%2dY”.

The Microterm ACT-IV needs the current row and column sent preceded by a ^T, with the row and column simply encoded in binary, “cup=^T%p1%c%p2%c”. Terminals which use “%c” need to be able to backspace the cursor (cub1), and to move the cursor up one line on the screen (cuu1). This is necessary because it is not always safe to transmit \n ^D and \r, as the system may change or discard them. (The library routines dealing with terminfo set tty modes so that tabs are never expanded, so \t is safe to send. This turns out to be essential for the Ann Arbor 4080.)

A final example is the LSI ADM -3a, which uses row and column offset by a blank character, thus “cup=\E=%p1%’ ’%+%c%p2%’ ’%+%c”. After sending ’\E=’, this pushes the first parameter, pushes the ASCII value for a space (32), adds them (pushing the sum on the stack in place of the two previous values) and outputs that value as a character. Then the same is done for the second parameter. More complex arithmetic is possible using the stack.

If the terminal has row or column absolute cursor addressing, these can be given as single parameter capabilities hpa (horizontal position absolute) and vpa (vertical position absolute). Sometimes these are shorter than the more general two parameter sequence (as with the hp2645) and can be used in preference to cup . If there are parameterized local motions (e.g., move n spaces to the right) these can be given as cud, cub, cuf, and cuu with a single parameter indicating how many spaces to move. These are primarily useful if the terminal does not have cup, such as the TEKTRONIX 4025.

Cursor Motions
If the terminal has a fast way to home the cursor (to very upper left corner of screen) then this can be given as home; similarly a fast way of getting to the lower left-hand corner can be given as ll; this may involve going up with cuu1 from the home position, but a program should never do this itself (unless ll does) because it can make no assumption about the effect of moving up from the home position. Note that the home position is the same as addressing to (0,0): to the top left corner of the screen, not of memory. (Thus, the \EH sequence on HP terminals cannot be used for home.)

Area Clears
If the terminal can clear from the current position to the end of the line, leaving the cursor where it is, this should be given as el. If the terminal can clear from the current position to the end of the display, then this should be given as ed. Ed is only defined from the first column of a line. (Thus, it can be simulated by a request to delete a large number of lines, if a true ed is not available.)

Insert/delete line and vertical motions
If the terminal can open a new blank line before the line where the cursor is, this should be given as il1; this is done only from the first position of a line. The cursor must then appear on the newly blank line. If the terminal can delete the line which the cursor is on, then this should be given as dl1; this is done only from the first position on the line to be deleted. Versions of il1 and dl1 which take a single parameter and insert or delete that many lines can be given as il and dl. If the terminal has a settable scrolling region (like the vt100) the command to set this can be described with the csr capability, which takes two parameters: the top and bottom lines of the scrolling region. The cursor position is, alas, undefined after using this command.

It is possible to get the effect of insert or delete line using csr on a properly chosen region; the sc and rc (save and restore cursor) commands may be useful for ensuring that your synthesized insert/delete string does not move the cursor. (Note that the ncurses(3x) library does this synthesis automatically, so you need not compose insert/delete strings for an entry with csr).

Yet another way to construct insert and delete might be to use a combination of index with the memory-lock feature found on some terminals (like the HP-700/90 series, which however also has insert/delete).

Inserting lines at the top or bottom of the screen can also be done using ri or ind on many terminals without a true insert/delete line, and is often faster even on terminals with those features.

The boolean non_dest_scroll_region should be set if each scrolling window is effectively a view port on a screen-sized canvas. To test for this capability, create a scrolling region in the middle of the screen, write something to the bottom line, move the cursor to the top of the region, and do ri followed by dl1 or ind. If the data scrolled off the bottom of the region by the ri re-appears, then scrolling is non-destructive. System V and XSI Curses expect that ind, ri, indn, and rin will simulate destructive scrolling; their documentation cautions you not to define csr unless this is true. This curses implementation is more liberal and will do explicit erases after scrolling if ndstr is defined.

If the terminal has the ability to define a window as part of memory, which all commands affect, it should be given as the parameterized string wind. The four parameters are the starting and ending lines in memory and the starting and ending columns in memory, in that order.

If the terminal can retain display memory above, then the da capability should be given; if display memory can be retained below, then db should be given. These indicate that deleting a line or scrolling may bring non-blank lines up from below or that scrolling back with ri may bring down non-blank lines.

Insert/Delete Character
There are two basic kinds of intelligent terminals with respect to insert/delete character which can be described using terminfo. The most common insert/delete character operations affect only the characters on the current line and shift characters off the end of the line rigidly. Other terminals, such as the Concept 100 and the Perkin Elmer Owl, make a distinction between typed and untyped blanks on the screen, shifting upon an insert or delete only to an untyped blank on the screen which is either eliminated, or expanded to two untyped blanks. You can determine the kind of terminal you have by clearing the screen and then typing text separated by cursor motions. Type “abc    def” using local cursor motions (not spaces) between the “abc” and the “def”. Then position the cursor before the “abc” and put the terminal in insert mode. If typing characters causes the rest of the line to shift rigidly and characters to fall off the end, then your terminal does not distinguish between blanks and untyped positions. If the “abc” shifts over to the “def” which then move together around the end of the current line and onto the next as you insert, you have the second type of terminal, and should give the capability in, which stands for “insert null”. While these are two logically separate attributes (one line vs. multi-line insert mode, and special treatment of untyped spaces) we have seen no terminals whose insert mode cannot be described with the single attribute.

Terminfo can describe both terminals which have an insert mode, and terminals which send a simple sequence to open a blank position on the current line. Give as smir the sequence to get into insert mode. Give as rmir the sequence to leave insert mode. Now give as ich1 any sequence needed to be sent just before sending the character to be inserted. Most terminals with a true insert mode will not give ich1; terminals which send a sequence to open a screen position should give it here.

If your terminal has both, insert mode is usually preferable to ich1. Technically, you should not give both unless the terminal actually requires both to be used in combination. Accordingly, some non-curses applications get confused if both are present; the symptom is doubled characters in an update using insert. This requirement is now rare; most ich sequences do not require previous smir, and most smir insert modes do not require ich1 before each character. Therefore, the new curses actually assumes this is the case and uses either rmir/smir or ich/ich1 as appropriate (but not both). If you have to write an entry to be used under new curses for a terminal old enough to need both, include the rmir/smir sequences in ich1.

If post insert padding is needed, give this as a number of milliseconds in ip (a string option). Any other sequence which may need to be sent after an insert of a single character may also be given in ip. If your terminal needs both to be placed into an ’insert mode’ and a special code to precede each inserted character, then both smir/rmir and ich1 can be given, and both will be used. The ich capability, with one parameter, n, will repeat the effects of ich1 n times.

It is occasionally necessary to move around while in insert mode to delete characters on the same line (e.g., if there is a tab after the insertion position). If your terminal allows motion while in insert mode you can give the capability mir to speed up inserting in this case. Omitting mir will affect only speed. Some terminals (notably Datamedia’s) must not have mir because of the way their insert mode works.

Finally, you can specify dch1 to delete a single character, dch with one parameter, n, to delete n characters, and delete mode by giving smdc and rmdc to enter and exit delete mode (any mode the terminal needs to be placed in for dch1 to work).

A command to erase n characters (equivalent to outputting n blanks without moving the cursor) can be given as ech with one parameter.

Highlighting, Underlining, and Visible Bells
If your terminal has one or more kinds of display attributes, these can be represented in a number of different ways. You should choose one display form as standout mode, representing a good, high contrast, easy-on-the-eyes, format for highlighting error messages and other attention getters. (If you have a choice, reverse video plus half-bright is good, or reverse video alone.) The sequences to enter and exit standout mode are given as smso and rmso, respectively. If the code to change into or out of standout mode leaves one or even two blank spaces on the screen, as the TVI 912 and Teleray 1061 do, then xmc should be given to tell how many spaces are left.

Codes to begin underlining and end underlining can be given as smul and rmul respectively. If the terminal has a code to underline the current character and move the cursor one space to the right, such as the Microterm Mime, this can be given as uc.

Other capabilities to enter various highlighting modes include blink (blinking) bold (bold or extra bright) dim (dim or half-bright) invis (blanking or invisible text) prot (protected) rev (reverse video) sgr0 (turn off all attribute modes) smacs (enter alternate character set mode) and rmacs (exit alternate character set mode). Turning on any of these modes singly may or may not turn off other modes.

If there is a sequence to set arbitrary combinations of modes, this should be given as sgr (set attributes), taking 9 parameters. Each parameter is either 0 or 1, as the corresponding attribute is on or off. The 9 parameters are, in order: standout, underline, reverse, blink, dim, bold, blank, protect, alternate character set. Not all modes need be supported by sgr, only those for which corresponding separate attribute commands exist.

Terminals with the ’’magic cookie’’ glitch (xmc) deposit special ’’cookies’’ when they receive mode-setting sequences, which affect the display algorithm rather than having extra bits for each character. Some terminals, such as the HP 2621, automatically leave standout mode when they move to a new line or the cursor is addressed. Programs using standout mode should exit standout mode before moving the cursor or sending a newline, unless the msgr capability, asserting that it is safe to move in standout mode, is present.

If the terminal has a way of flashing the screen to indicate an error quietly (a bell replacement) then this can be given as flash; it must not move the cursor.

If the cursor needs to be made more visible than normal when it is not on the bottom line (to make, for example, a non-blinking underline into an easier to find block or blinking underline) give this sequence as cvvis. If there is a way to make the cursor completely invisible, give that as civis. The capability cnorm should be given which undoes the effects of both of these modes.

If the terminal needs to be in a special mode when running a program that uses these capabilities, the codes to enter and exit this mode can be given as smcup and rmcup. This arises, for example, from terminals like the Concept with more than one page of memory. If the terminal has only memory relative cursor addressing and not screen relative cursor addressing, a one screen-sized window must be fixed into the terminal for cursor addressing to work properly. This is also used for the TEKTRONIX 4025, where smcup sets the command character to be the one used by terminfo.

If your terminal correctly generates underlined characters (with no special codes needed) even though it does not overstrike, then you should give the capability ul. If overstrikes are erasable with a blank, then this should be indicated by giving eo.

Keypad Handling
If the terminal has a keypad that transmits codes when the keys are pressed, this information can be given. Note that it is not possible to handle terminals where the keypad only works in local (this applies, for example, to the unshifted HP 2621 keys). If the keypad can be set to transmit or not transmit, give these codes as smkx and rmkx. Otherwise the keypad is assumed to always transmit. The codes sent by the left arrow, right arrow, up arrow, down arrow, and home keys can be given as kcub1, kcuf1, kcuu1, kcud1, and khome respectively. If there are function keys such as f0, f1, ..., f10, the codes they send can be given as kf0, kf1, ..., kf10. If these keys have labels other than the default f0 through f10, the labels can be given as lf0, lf1, ..., lf10. The codes transmitted by certain other special keys can be given: kll (home down), kbs (backspace), ktbc (clear all tabs), kctab (clear the tab stop in this column), kclr (clear screen or erase key), kdch1 (delete character), kdl1 (delete line), krmir (exit insert mode), kel (clear to end of line), ked (clear to end of screen), kich1 (insert character or enter insert mode), kil1 (insert line), knp (next page), kpp (previous page), kind (scroll forward/down), kri (scroll backward/up), khts (set a tab stop in this column). In addition, if the keypad has a 3 by 3 array of keys including the four arrow keys, the other five keys can be given as ka1, ka3, kb2, kc1, and kc3. These keys are useful when the effects of a 3 by 3 directional pad are needed.

Tabs and Initialization
If the terminal has hardware tabs, the command to advance to the next tab stop can be given as ht (usually control I). A ’’back-tab’’ command which moves leftward to the next tab stop can be given as cbt. By convention, if the teletype modes indicate that tabs are being expanded by the computer rather than being sent to the terminal, programs should not use ht or cbt even if they are present, since the user may not have the tab stops properly set. If the terminal has hardware tabs which are initially set every n spaces when the terminal is powered up, the numeric parameter it is given, showing the number of spaces the tabs are set to. This is normally used by the tset command to determine whether to set the mode for hardware tab expansion, and whether to set the tab stops. If the terminal has tab stops that can be saved in non-volatile memory, the terminfo description can assume that they are properly set.

Other capabilities include is1, is2, and is3, initialization strings for the terminal, iprog, the path name of a program to be run to initialize the terminal, and if, the name of a file containing long initialization strings. These strings are expected to set the terminal into modes consistent with the rest of the terminfo description. They are normally sent to the terminal, by the tset program, each time the user logs in. They will be printed in the following order: is1; is2; setting tabs using tbc and hts; if; running the program iprog; and finally is3. Most initialization is done with is2. Special terminal modes can be set up without duplicating strings by putting the common sequences in is2 and special cases in is1 and is3. A pair of sequences that does a harder reset from a totally unknown state can be analogously given as rs1, rs2, rf, and rs3, analogous to is2 and if. These strings are output by the reset program, which is used when the terminal gets into a wedged state. Commands are normally placed in rs2 and rf only if they produce annoying effects on the screen and are not necessary when logging in. For example, the command to set the vt100 into 80-column mode would normally be part of is2, but it causes an annoying glitch of the screen and is not normally needed since the terminal is usually already in 80 column mode.

If there are commands to set and clear tab stops, they can be given as tbc (clear all tab stops) and hts (set a tab stop in the current column of every row). If a more complex sequence is needed to set the tabs than can be described by this, the sequence can be placed in is2 or if.

Delays and Padding
Many older and slower terminals don’t support either XON/XOFF or DTR handshaking, including hard copy terminals and some very archaic CRTs (including, for example, DEC VT100s). These may require padding characters after certain cursor motions and screen changes.

If the terminal uses xon/xoff handshaking for flow control (that is, it automatically emits ^S back to the host when its input buffers are close to full), set xon. This capability suppresses the emission of padding. You can also set it for memory-mapped console devices effectively that don’t have a speed limit. Padding information should still be included so that routines can make better decisions about relative costs, but actual pad characters will not be transmitted.

If pb (padding baud rate) is given, padding is suppressed at baud rates below the value of pb. If the entry has no padding baud rate, then whether padding is emitted or not is completely controlled by xon.

If the terminal requires other than a null (zero) character as a pad, then this can be given as pad. Only the first character of the pad string is used.

Status Lines
Some terminals have an extra ’status line’ which is not normally used by software (and thus not counted in the terminal’s lines capability).

The simplest case is a status line which is cursor-addressable but not part of the main scrolling region on the screen; the Heathkit H19 has a status line of this kind, as would a 24-line VT100 with a 23-line scrolling region set up on initialization. This situation is indicated by the hs capability.

Some terminals with status lines need special sequences to access the status line. These may be expressed as a string with single parameter tsl which takes the cursor to a given zero-origin column on the status line. The capability fsl must return to the main-screen cursor positions before the last tsl. You may need to embed the string values of sc (save cursor) and rc (restore cursor) in tsl and fsl to accomplish this.

The status line is normally assumed to be the same width as the width of the terminal. If this is untrue, you can specify it with the numeric capability wsl.

A command to erase or blank the status line may be specified as dsl.

The boolean capability eslok specifies that escape sequences, tabs, etc. work ordinarily in the status line.

The ncurses implementation does not yet use any of these capabilities. They are documented here in case they ever become important.

Line Graphics
Many terminals have alternate character sets useful for forms-drawing. Terminfo and curses build in support for the drawing characters supported by the VT100, with some characters from the AT&T 4410v1 added. This alternate character set may be specified by the acsc capability.