Ubuntu Manpage: slk_init, slk_set, slk_wset, slk_refresh, slk_noutrefresh, slk_label, slk_clear, slk_restore, slk

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

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.