slk_color – curses soft label routines
int slk_init(int fmt);
int slk_set(int labnum, const char *label, int fmt);
char *slk_label(int labnum);
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 color_pair_number, void* opts);
int slk_color(short color_pair_number);
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 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 does not try to use any hardware support for this
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-justified, respectively, within the
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
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).
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_attroff, slk_attron, slk_clear, slk_noutrefresh, slk_refresh, slk_touch
return an error
if the terminal or the softkeys were not initialized.
The XSI Curses standard, Issue 4, describes these functions. 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.