- The slk* functions manipulate the set of soft function-key
- labels that exist on many terminals. For those terminals
- that do not have soft labels, curses takes over the bottom
- line of stdscr, reducing the size of stdscr and the vari-
- able LINES. curses standardizes on eight labels of up to
- eight characters each. In addition to this, the ncurses
- implementation supports a mode where it simulates 12
- labels of up to five characters each. This is most common
- for todays PC like enduser devices. Please note that
- ncurses simulates this mode by taking over up to two lines
- at the bottom of the screen, it doesn't try to use any
- hardware support for this mode.
-
- The slk_init routine must be called before initscr or
- newterm is called. If initscr eventually uses a line from
- stdscr to emulate the soft labels, then fmt determines how
- the labels are arranged on the screen. Setting fmt to 0
- indicates a 3-2-3 arrangement of the labels, 1 indicates a
- 4-4 arrangement and 2 indicates the PC like 4-4-4 mode. If
- fmt is set to 3, it is again the PC like 4-4-4 mode, but
- in addition an index line is generated, helping the user
- to identify the key numbers easily.
-
- The slk_set routine requires labnum to be a label number,
- from 1 to 8 (resp. 12); label must be the string to be put
- on the label, up to eight (resp. five) characters in
- length. A null string or a null pointer sets up a blank
- label. fmt is either 0, 1, or 2, indicating whether the
- label is to be left-justified, centered, or right-justi-
- fied, respectively, within the label.
-
- The slk_refresh and slk_noutrefresh routines correspond to
- the wrefresh and wnoutrefresh routines.
-
- The slk_label routine returns the current label for label
- number labnum, with leading and trailing blanks stripped.
-
- The slk_clear routine clears the soft labels from the
- screen.
-
- The slk_restore routine, restores the soft labels to the
- screen after a slk_clear has been performed.
-
- The slk_touch routine forces all the soft labels to be
- output the next time a slk_noutrefresh is performed.
-
- The slk_attron, slk_attrset, slk_attroff and slk_attr rou-
- tines correspond to attron, attrset, attroff and attr_get.
- They have an effect only if soft labels are simulated on
- the bottom line of the screen. The default highlight for
- soft keys is A_STANDOUT (as in System V curses, which does
- not document this fact).
-
- The slk_color routine corresponds to color_set. It has an
- effect only if soft labels are simulated on the bottom
- line of the screen.
+
+ These functions manipulate the soft function key labels that some
+ hardware terminals support. For those terminals that do not have soft
+ labels, curses takes over the bottom line of stdscr, reducing its
+ vertical size and the value of LINES by one. By default, curses uses
+ eight labels of up to eight characters each.
+ ncurses furthermore supports a mode comprising twelve labels of up to
+ five characters each, following a convention associated with the IBM
+ PC/AT keyboard. ncurses simulates this mode by taking over up to two
+ lines at the bottom of the screen; it does not try to use any hardware
+ support for this mode.
-
-
RETURN VALUE
- These routines return ERR upon failure and OK (SVr4 speci-
- fies only "an integer value other than ERR") upon success-
- ful completion. slk_attr returns the attribute used for
- the soft keys.
- slk_label returns NULL on error.
+
+ slk_init must be called before initscr or newterm. If initscr
+ eventually uses a line from stdscr to emulate the soft labels, then fmt
+ determines how the labels are arranged on the screen.
+ 0 indicates a 3-2-3 arrangement of the labels.
-
-
NOTES
- Most applications would use slk_noutrefresh because a wre-
- fresh is likely to follow soon.
+ 1 indicates a 4-4 arrangement
+ 2 indicates the PC-like 4-4-4 mode.
-
-
PORTABILITY
- The XSI Curses standard, Issue 4, describes these func-
- tions. It changes the argument type of the attribute-
- manipulation functions slk_attron, slk_attroff,
- slk_attrset to be attr_t, and adds const qualifiers. The
- format codes 2 and 3 for slk_init() and the function
- slk_attr are specific to ncurses.
+ 3 is again the PC-like 4-4-4 mode, but in addition an index line is
+ generated, helping the user to associate each label with its
+ numbered function key. LINES and the vertical size of stdscr are
+ further reduced.
+
+ Populate the labels with normal strings (slk_set) or wide-character
+ strings (slk_wset). Each function takes three parameters.
-
-
SEE ALSO
- curses(3x), curs_attr(3x), curs_initscr(3x),
- curs_refresh(3x)
+ labnum is the label number, from 1 to 8 (12 if fmt in slk_init is 2 or
+ 3);
+
+ label is be the string to put on the label, up to eight (five if fmt
+ in slk_init is 2 or 3) characters in length. A empty string or
+ a null pointer sets up a blank label.
+
+ align is 0, 1, or 2, aligning label to the left, center, or right,
+ respectively, within the 8 (5) character cells housing it.
+
+ slk_label obtains the string assigned to label number labnum, with any
+ leading and trailing blanks stripped.
+
+
+
+ slk_refresh and slk_noutrefresh affect the soft key label lines as
+ wrefresh and wnoutrefresh do the curses window.
+
+ The slk_clear routine clears the soft labels from the screen.
+
+ The slk_restore routine restores the soft labels to the screen after a
+ slk_clear has been performed.
+
+ The slk_touch routine forces all the soft labels to be output the next
+ time a slk_noutrefresh is performed.
+
+ The slk_attron, slk_attrset, slk_attroff, and slk_attr routines
+ correspond to attron, attrset, attroff, and attr_get, respectively.
+ They have an effect only if soft labels are simulated on the bottom
+ line of the screen. The default highlight for soft key labels is
+ A_STANDOUT (as in System V curses, which does not document this fact).
+
+ The slk_color routine corresponds to color_set. It has an effect only
+ if soft labels are simulated on the bottom line of the screen.
+ Because slk_color accepts only short (signed 16-bit integer) values,
+ this implementation provides extended_slk_color, which accepts an int
+ value of at least 32 bits.
+
+ Routines that return an integer return ERR upon failure and OK (SVr4
+ specifies only "an integer value other than ERR") upon successful
+ completion.
+ X/Open Curses defines no error conditions.
+ In this implementation
+ slk_attr
+ returns the attribute used for the soft keys.
+ slk_attroff, slk_attron, slk_clear, slk_noutrefresh, slk_refresh,
+ slk_touch
+ return an error if the terminal or the softkeys were not
+ initialized.
+ slk_attrset
+ returns an error if the terminal or the softkeys were not
+ initialized.
+ slk_attr_set
+ returns an error if the terminal or the softkeys were not
+ initialized, or the color pair is outside the range
+ 0..COLOR_PAIRS-1.
+ slk_color
+ returns an error if the terminal or the softkeys were not
+ initialized, or the color pair is outside the range
+ 0..COLOR_PAIRS-1.
+ slk_init
+ returns an error if the format parameter is outside the range
+ 0..3.
+ slk_label
+ returns NULL on error.
+ slk_set
+ returns an error if the terminal or the softkeys were not
+ initialized, or the labnum parameter is outside the range of
+ label counts, or if the format parameter is outside the range
+ 0..2, or if memory for the labels cannot be allocated.
+
+ X/Open Curses documents the opts argument as reserved for future use,
+ saying that it must be null. This implementation uses that parameter
+ in ABI 6 for the functions which have a color pair parameter to support
+ extended color pairs.
+ For functions which modify the color, e.g., slk_attr_set, if opts is
+ set it is treated as a pointer to int, and used to set the color pair
+ instead of the short pair parameter.
+
+ X/Open Curses, Issue 4 describes these functions, with some differences
+ from SVr4 curses:
+ o X/Open added functions like the SVr4 attribute-manipulation
+ functions slk_attron, slk_attroff, and slk_attrset, but which use
+ attr_t parameters (rather than chtype), along with a reserved opts
+ parameter.
+ Two of these new functions (unlike the SVr4 functions) have no
+ provision for color: slk_attr_on and slk_attr_off.
+ The third function (slk_attr_set) has a color pair parameter.
+ o It added const qualifiers to parameters (unnecessarily), and
+ o It added slk_color.
+ Although slk_start is declared in the curses header file, it was not
+ documented by SVr4 other than its presence in a list of libtermlib.so.1
+ symbols. Reading the source code (i.e., Illumos):
+ oslk_start has two parameters:
+ ong (number of groups) and
+ ogp (group pointer).
+ o Soft-key groups are an array of ng integers.
+ o In SVr4, slk_init calls slk_start passing a null for gp. For this
+ case, slk_start uses the number of groups ng (3 for the 3-2-3
+ layout, 2 for the 4-4 layout) which slk_init provided.
+ If ng is neither 2 or 3, slk_start checks the terminfo fln
+ (label_format) capability, interpreting that as a comma-separated
+ list of numbers, e.g., "3,2,3" for the 3-2-3 layout.
+ Finally, if there is no fln capability, slk_start returns ERR.
+ o If slk_start is given a non-null gp, it copies the ng elements of
+ the group of soft-keys, up to 16.
+ If there are more than 16 elements, slk_start returns an error.
+ o The format codes 2 and 3 for slk_init were added by ncurses in
+ 1996. PDCurses 2.4 added this feature in 2001.
+ The function slk_attr was added by ncurses in 1996.
+ X/Open Curses does not specify a limit for the number of colors and
+ color pairs which a terminal can support. However, in its use of short
+ for the parameters, it carries over SVr4's implementation detail for
+ the compiled terminfo database, which uses signed 16-bit numbers. This
+ implementation provides extended versions of those functions which use
+ int parameters, allowing applications to use larger color- and pair-
+ numbers.
+