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       level curses routines


       #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);


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

       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().

       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 and, after an endwin, by doupdate, so they
       normally are not called.

       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.

       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.

       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.

       The  ripoffline  routine  provides  access  to  the  same facility that
       slk_init [see curs_slk(3X)] uses to reduce  the  size  of  the  screen.
       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.

       The napms routine is used to sleep for ms milliseconds.


       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.

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


       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.


       The  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 se-
       mantics for the return value.


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

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