|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.|
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_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).
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 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, or opts is not null. 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.
Most applications would use slk_noutrefresh because a wrefresh is likely to follow soon.
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.
curses(3X), curs_attr(3X), curs_initscr(3X), curs_refresh(3X), curs_variables(3X).