# curs_kernel 3x

    curs_kernel(3x)                                                curs_kernel(3x)

## NAME

           def_prog_mode, def_shell_mode, reset_prog_mode, reset_shell_mode,
           resetty, savetty, getsyx, setsyx, ripoffline, curs_set, napms - low-
           level curses routines

## SYNOPSIS

           #include <curses.h>

           int def_prog_mode(void);
           int def_shell_mode(void);

           int reset_prog_mode(void);
           int reset_shell_mode(void);

           int resetty(void);
           int savetty(void);

           void getsyx(int y, int x);
           void setsyx(int y, int x);

           int ripoffline(int line, int (*init)(WINDOW *, int));
           int curs_set(int visibility);
           int napms(int ms);

## DESCRIPTION

           The following routines give low-level access to various curses capabil-
           ities.  These routines typically are used inside library routines.

### def_prog_mode, def_shell_mode

           The def_prog_mode and def_shell_mode routines save the current terminal
           modes as the "program" (in curses) or "shell" (not in curses) state for
           use by the reset_prog_mode and reset_shell_mode routines.  This is done
           automatically  by initscr.  There is one such save area for each screen
           context allocated by newterm.

### reset_prog_mode, reset_shell_mode

           The reset_prog_mode and reset_shell_mode routines restore the  terminal
           to  "program"  (in curses) or "shell" (out of curses) state.  These are
           done automatically by endwin(3x) and, after an endwin, by doupdate,  so
           they normally are not called.

### resetty, savetty

           The resetty and savetty routines save and restore the state of the ter-
           minal modes.  savetty saves the current state in a buffer  and  resetty
           restores the state to what it was at the last call to savetty.

### getsyx

           The  getsyx  routine  returns  the  current  coordinates of the virtual
           screen cursor in y and x.  If leaveok is currently TRUE, then -1,-1  is
           returned.  If lines have been removed from the top of the screen, using
           ripoffline, y and x include these lines; therefore, y and x  should  be
           used only as arguments for setsyx.

           Few applications will use this feature, most use getyx instead.

### setsyx

           The  setsyx routine sets the virtual screen cursor to y, x.  If y and x
           are both -1, then leaveok is set.  The two routines getsyx  and  setsyx
           are  designed to be used by a library routine, which manipulates curses
           windows but does not want to change the current position  of  the  pro-
           gram's cursor.  The library routine would call getsyx at the beginning,
           do its manipulation of its own windows, do a wnoutrefresh on  its  win-
           dows, call setsyx, and then call doupdate.

           Few applications will use this feature, most use wmove instead.

### ripoffline

           The  ripoffline  routine  provides  access  to  the  same facility that
           slk_init [see curs_slk(3x)] uses to reduce  the  size  of  the  screen.
           ripoffline  must be called before initscr or newterm is called, to pre-
           pare these initial actions:

           o   If line is positive, a line is removed from the top of stdscr.

           o   if line is negative, a line is removed from the bottom.

           When the resulting initialization is done inside initscr,  the  routine
           init (supplied by the user) is called with two arguments:

           o   a window pointer to the one-line window that has been allocated and

           o   an integer with the number of columns in the window.

           Inside  this  initialization  routine,  the integer variables LINES and
           COLS (defined in <curses.h>) are not guaranteed to be accurate and wre-
           fresh or doupdate must not be called.  It is allowable to call wnoutre-
           fresh during the initialization routine.

           ripoffline can be called up to five times  before  calling  initscr  or
           newterm.

### curs_set

           The  curs_set  routine  sets  the cursor state to invisible, normal, or
           very visible for visibility equal to 0, 1, or 2 respectively.   If  the
           terminal  supports  the visibility requested, the previous cursor state
           is returned; otherwise, ERR is returned.

### napms

           The napms routine is used to sleep for ms milliseconds.

## RETURN VALUE

           Except for curs_set, these routines always return OK.

           curs_set returns the previous cursor state, or  ERR  if  the  requested
           visibility is not supported.

           X/Open defines no error conditions.  In this implementation

           def_prog_mode, def_shell_mode, reset_prog_mode, reset_shell_mode
                return an error if the terminal was not initialized, or if the I/O
                call to obtain the terminal settings fails.

           ripoffline
                returns an error if the maximum number of ripped-off lines exceeds
                the maximum (NRIPS = 5).

## NOTES

           Note that getsyx is a macro, so & is not necessary before the variables
           y and x.

           Older SVr4 man pages warn that the return value of  curs_set  "is  cur-
           rently  incorrect".   This  implementation gets it right, but it may be
           unwise to count on the correctness of the return value anywhere else.

           Both ncurses and SVr4 will call curs_set in endwin if curs_set has been
           called  to make the cursor other than normal, i.e., either invisible or
           very visible.  There is no way for ncurses  to  determine  the  initial
           cursor state to restore that.

## PORTABILITY

           The virtual screen functions setsyx and getsyx are not described in the
           XSI Curses standard, Issue 4.  All other functions are as described  in
           XSI Curses.

           The  SVr4  documentation  describes  setsyx and getsyx as having return
           type int.  This is misleading, as they are macros  with  no  documented
           semantics for the return value.

## SEE ALSO

           curses(3x),   curs_initscr(3x),   curs_outopts(3x),   curs_refresh(3x),
           curs_scr_dump(3x), curs_slk(3x), curs_variables(3x).

                                                                   curs_kernel(3x)