Provided by: ncurses-doc_6.1-1ubuntu1.18.04.1_all bug

NAME

       slk_init, slk_set, slk_wset, slk_refresh, slk_noutrefresh, slk_label, slk_clear,
       slk_restore, slk_touch, slk_attron, slk_attrset, slk_attroff, slk_attr_on, slk_attr_set,
       slk_attr_off, slk_attr, slk_color, extended_slk_color - curses soft label routines

SYNOPSIS

       #include <curses.h>

       int slk_init(int fmt);

       int slk_set(int labnum, const char *label, int fmt);
       int slk_wset(int labnum, const wchar_t *label, int fmt);

       char *slk_label(int labnum);

       int slk_refresh(void);
       int slk_noutrefresh(void);
       int slk_clear(void);
       int slk_restore(void);
       int slk_touch(void);

       int slk_attron(const chtype attrs);
       int slk_attroff(const chtype attrs);
       int slk_attrset(const chtype attrs);
       int slk_attr_on(attr_t attrs, void* opts);
       int slk_attr_off(const attr_t attrs, void * opts);
       int slk_attr_set(const attr_t attrs, short pair, void* opts);

       attr_t slk_attr(void);

       int slk_color(short pair);
       /* extension */
       int extended_slk_color(int pair);

DESCRIPTION

       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 variable 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 useful for PC-like enduser devices.  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.

   Initialization
       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:

          0  indicates a 3-2-3 arrangement of the labels.

          1  indicates a 4-4 arrangement

          2  indicates the PC-like 4-4-4 mode.

          3  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.

   Labels
       The  slk_set  routine  (and the slk_wset routine for the wide-character library) has three
       parameters:

          labnum
               is the label number, from 1 to 8 (12 for fmt in slk_init is 2 or 3);

          label
               is be the string to put on the label, up to eight (five for fmt in slk_init  is  2
               or  3)  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-justified, respectively, within the label.

       The  slk_label routine returns the current label for label number labnum, with leading and
       trailing blanks stripped.

   Screen updates
       The slk_refresh and slk_noutrefresh routines correspond to the wrefresh  and  wnoutrefresh
       routines.

       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.

   Video attributes
       The  slk_attron,  slk_attrset,  slk_attroff  and  slk_attr  routines 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).

   Colors
       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 integer value, e.g., 32-bits.

RETURN VALUE

       These routines return ERR upon failure and OK (SVr4 specifies only "an integer value other
       than ERR") upon successful completion.

       X/Open 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.

EXTENSIONS

       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.

NOTES

       Most applications would use slk_noutrefresh because a wrefresh is likely to follow soon.

PORTABILITY

       The  XSI Curses standard, Issue 4, described the soft-key functions, with some differences
       from SVr4 curses:

       •   It  added  functions  like  the  SVr4  attribute-manipulation  functions   slk_attron,
           slk_attroff,  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.

       •   It added const qualifiers to parameters (unnecessarily), and

       •   It added slk_color.

       The format codes 2 and 3 for slk_init and the function slk_attr are specific to ncurses.

       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
       short parameters, allowing applications to use larger color- and pair-numbers.

SEE ALSO

       ncurses(3NCURSES),       attr(3NCURSES),       initscr(3NCURSES),       refresh(3NCURSES),
       curses_variables(3NCURSES).

                                                                                    slk(3NCURSES)