1curs_outopts(3X)                                              curs_outopts(3X)
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NAME

6       clearok, idlok, idcok, immedok, leaveok, setscrreg, wsetscrreg,
7       scrollok, nl, nonl - curses output options
8

SYNOPSIS

10       #include <curses.h>
11
12       int clearok(WINDOW *win, bool bf);
13       int idlok(WINDOW *win, bool bf);
14       void idcok(WINDOW *win, bool bf);
15       void immedok(WINDOW *win, bool bf);
16       int leaveok(WINDOW *win, bool bf);
17       int setscrreg(int top, int bot);
18       int wsetscrreg(WINDOW *win, int top, int bot);
19       int scrollok(WINDOW *win, bool bf);
20       int nl(void);
21       int nonl(void);
22

DESCRIPTION

24       These routines set options that change the style of output within curs‐
25       es.   All  options are initially FALSE, unless otherwise stated.  It is
26       not necessary to turn these options off before calling endwin.
27
28       If clearok is called with TRUE as argument, the next call  to  wrefresh
29       with this window will clear the screen completely and redraw the entire
30       screen from scratch.  This is useful when the contents  of  the  screen
31       are  uncertain, or in some cases for a more pleasing visual effect.  If
32       the win argument to clearok is the global  variable  curscr,  the  next
33       call  to  wrefresh  with any window causes the screen to be cleared and
34       repainted from scratch.
35
36       If idlok is called with TRUE as second argument, curses considers using
37       the  hardware  insert/delete  line  feature  of  terminals so equipped.
38       Calling idlok with FALSE as second argument disables use of line inser‐
39       tion  and deletion.  This option should be enabled only if the applica‐
40       tion needs insert/delete line, for example, for a screen editor.  It is
41       disabled by default because insert/delete line tends to be visually an‐
42       noying when used in applications where it is not really needed.  If in‐
43       sert/delete line cannot be used, curses redraws the changed portions of
44       all lines.
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46       If idcok is called with FALSE as second argument, curses no longer con‐
47       siders  using the hardware insert/delete character feature of terminals
48       so equipped.  Use of character insert/delete  is  enabled  by  default.
49       Calling  idcok with TRUE as second argument re-enables use of character
50       insertion and deletion.
51
52       If immedok is called with TRUE as argument, any change  in  the  window
53       image, such as the ones caused by waddch, wclrtobot, wscrl, etc., auto‐
54       matically cause a call to wrefresh.  However, it  may  degrade  perfor‐
55       mance  considerably, due to repeated calls to wrefresh.  It is disabled
56       by default.
57
58       Normally, the hardware cursor is left at the  location  of  the  window
59       cursor  being  refreshed.   The  leaveok option allows the cursor to be
60       left wherever the update happens to leave it.  It is useful for  appli‐
61       cations  where  the  cursor  is not used, since it reduces the need for
62       cursor motions.
63
64       The setscrreg and wsetscrreg routines allow the application  programmer
65       to set a software scrolling region in a window.  The top and bot param‐
66       eters are the line  numbers  of  the  top  and  bottom  margin  of  the
67       scrolling region.  (Line 0 is the top line of the window.)  If this op‐
68       tion and scrollok are enabled, an attempt to move off the bottom margin
69       line causes all lines in the scrolling region to scroll one line in the
70       direction of the first line.  Only the text of the window is  scrolled.
71       (Note  that this has nothing to do with the use of a physical scrolling
72       region capability in the terminal, like that in the VT100.  If idlok is
73       enabled and the terminal has either a scrolling region or insert/delete
74       line capability, they will probably be used by the output routines.)
75
76       The scrollok option controls what happens when the cursor of  a  window
77       is  moved  off  the edge of the window or scrolling region, either as a
78       result of a newline action on the bottom line, or typing the last char‐
79       acter of the last line.  If disabled, (bf is FALSE), the cursor is left
80       on the bottom line.  If enabled, (bf is TRUE), the window  is  scrolled
81       up one line (Note that to get the physical scrolling effect on the ter‐
82       minal, it is also necessary to call idlok).
83
84       The nl and nonl routines control whether the underlying display  device
85       translates  the return key into newline on input, and whether it trans‐
86       lates newline into return and line-feed on output (in either case,  the
87       call  addch('\n')  does  the  equivalent of return and line feed on the
88       virtual screen).  Initially, these translations do occur.  If you  dis‐
89       able  them  using  nonl,  curses will be able to make better use of the
90       line-feed capability, resulting in faster cursor motion.  Also,  curses
91       will then be able to detect the return key.
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RETURN VALUE

94       The  functions  setscrreg and wsetscrreg return OK upon success and ERR
95       upon failure.  All other routines that return an integer always  return
96       OK.
97
98       X/Open does not define any error conditions.
99
100       In this implementation, those functions that have a window pointer will
101       return an error if the window pointer is null.
102
103              wclrtoeol
104                   returns an error if the cursor position is about to wrap.
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106              wsetscrreg
107                   returns an error if the scrolling region limits extend out‐
108                   side the window.
109
110       X/Open  does  not define any error conditions.  This implementation re‐
111       turns an error if the window pointer is null.
112

PORTABILITY

114       These functions are described in the XSI Curses standard, Issue 4.
115
116       The XSI Curses standard is ambiguous on the question of  whether  raw()
117       should  disable  the  CRLF  translations controlled by nl() and nonl().
118       BSD curses did turn off these translations; AT&T curses  (at  least  as
119       late  as  SVr1) did not.  We choose to do so, on the theory that a pro‐
120       grammer requesting raw input wants a clean (ideally 8-bit  clean)  con‐
121       nection that the operating system will not alter.
122
123       Some  historic  curses implementations had, as an undocumented feature,
124       the ability to do the equivalent of clearok(..., 1)  by  saying  touch‐
125       win(stdscr) or clear(stdscr).  This will not work under ncurses.
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127       Earlier  System  V  curses implementations specified that with scrollok
128       enabled, any window modification triggering  a  scroll  also  forced  a
129       physical refresh.  XSI Curses does not require this, and ncurses avoids
130       doing it to perform better  vertical-motion  optimization  at  wrefresh
131       time.
132
133       The XSI Curses standard does not mention that the cursor should be made
134       invisible as a side-effect of leaveok.  SVr4 curses documentation  does
135       this,  but  the code does not.  Use curs_set to make the cursor invisi‐
136       ble.
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NOTES

139       Note that clearok, leaveok, scrollok, idcok, nl, nonl and setscrreg may
140       be macros.
141
142       The immedok routine is useful for windows that are used as terminal em‐
143       ulators.
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SEE ALSO

146       curses(3X),    curs_addch(3X),    curs_clear(3X),     curs_initscr(3X),
147       curs_scroll(3X), curs_refresh(3X), curs_variables(3X).
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151                                                              curs_outopts(3X)
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