The Single UNIX ® Specification, Version 2
Copyright © 1997 The Open Group


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


#include <curses.h>

int slk_attroff(const chtype attrs);

int slk_attr_off(const attr_t attrs, void *opts);

int slk_attron(const chtype attrs);

int slk_attr_on(const attr_t attrs, void *opts);

int slk_attrset(const chtype attrs);

int slk_attr_set(const attr_t attrs, short color_pair_number, void *opts);

int slk_clear(void);

int slk_color(short color_pair_number);

int slk_init(int fmt);

char *slk_label(int labnum);

int slk_noutrefresh(void);

int slk_refresh(void);

int slk_restore(void);

int slk_set(int labnum, const char *label, int justify);

int slk_touch(void);

int slk_wset(int labnum, const wchar_t *label, int justify);


The Curses interface manipulates 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 value of the LINES external variable. There can be up to eight labels of up to eight display columns each.

To use soft labels, slk_init() must be called before initscr(), newterm() or ripoffline() 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. Other values for fmt are unspecified.

The slk_init() function has the effect of calling ripoffline() to reserve one screen line to accommodate the requested format.

The slk_set() and slk_wset() functions specify the text of soft label number labnum, within the range from 1 to and including 8. The label argument is the string to be put on the label. With slk_set(), and slk_wset(), the width of the label is limited to eight column positions. A null string or a null pointer specifies a blank label. The justify argument can have the following values to indicate how to justify label within the space reserved for it:

Align the start of label with the start of the space
Center label within the space
Align the end of label with the end of the space

The slk_refresh() and slk_noutrefresh() functions correspond to the wrefresh() and wnoutrefresh() functions.

The slk_label() function obtains soft label number labnum.

The slk_clear() function immediately clears the soft labels from the screen.

The slk_restore() function immediately restores the soft labels to the screen after a call to slk_clear().

The slk_touch() function forces all the soft labels to be output the next time slk_noutrefresh() or slk_refresh() is called.

The slk_attron(), slk_attrset() and slk_attroff() functions correspond to attron(), attrset(), and attroff(). They have an effect only if soft labels are simulated on the bottom line of the screen.

The slk_attr_off(), slk_attr_on(), slk_attr_set(), and slk_color() functions correspond to slk_attroff(), slk_attron(), slk_attrset() and color_set() and thus support the attribute constants with the WA_ prefix and colour.

The opts argument is reserved for definition in a future edition of this document. Currently, the application must provide a null pointer as opts.


Upon successful completion, slk_label() returns the requested label with leading and trailing blanks stripped. Otherwise, it returns a null pointer.

Upon successful completion, the other functions return OK. Otherwise, they return ERR.


No errors are defined.


When using multi-byte character sets, applications should check the width of the string by calling mbstowcs() and then wcswidth() before calling slk_set(). When using wide characters, applications should check the width of the string by calling wcswidth() before calling slk_set().

Since the number of columns that a wide character string will occupy is codeset-specific, call wcwidth() and wcswidth() to check the number of column positions in the string before calling slk_wset().

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


attr_get(), attroff(), delscreen(), mbstowcs() (in the XSH specification), ripoffline(), wcswidth() (in the XSH specification), <curses.h>.

UNIX ® is a registered Trademark of The Open Group.
Copyright © 1997 The Open Group
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