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

6       clearok, idlok, idcok, immedok, leaveok, setscrreg, wsetscrreg,
7       scrollok - curses output options
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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 scrollok(WINDOW *win, bool bf);
18
19       int setscrreg(int top, int bot);
20       int wsetscrreg(WINDOW *win, int top, int bot);
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DESCRIPTION

23       These routines set options that change the style of output within curs‐
24       es.   All  options are initially FALSE, unless otherwise stated.  It is
25       not necessary to turn these options off before calling endwin(3X).
26
27   clearok
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.
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36   idlok
37       If idlok is called with TRUE as second argument, curses considers using
38       the  hardware  insert/delete  line  feature  of  terminals so equipped.
39       Calling idlok with FALSE as second argument disables use of line inser‐
40       tion  and deletion.  This option should be enabled only if the applica‐
41       tion needs insert/delete line, for example, for a screen editor.  It is
42       disabled by default because insert/delete line tends to be visually an‐
43       noying when used in applications where it is not really needed.  If in‐
44       sert/delete line cannot be used, curses redraws the changed portions of
45       all lines.
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47   idcok
48       If idcok is called with FALSE as second argument, curses no longer con‐
49       siders  using the hardware insert/delete character feature of terminals
50       so equipped.  Use of character insert/delete  is  enabled  by  default.
51       Calling  idcok with TRUE as second argument re-enables use of character
52       insertion and deletion.
53
54   immedok
55       If immedok is called with TRUE as argument, any change  in  the  window
56       image, such as the ones caused by waddch, wclrtobot, wscrl, etc., auto‐
57       matically cause a call to wrefresh.  However, it  may  degrade  perfor‐
58       mance  considerably, due to repeated calls to wrefresh.  It is disabled
59       by default.
60
61   leaveok
62       Normally, the hardware cursor is left at the  location  of  the  window
63       cursor  being  refreshed.   The  leaveok option allows the cursor to be
64       left wherever the update happens to leave it.  It is useful for  appli‐
65       cations  where  the  cursor  is not used, since it reduces the need for
66       cursor motions.
67
68   scrollok
69       The scrollok option controls what happens when the cursor of  a  window
70       is  moved  off  the edge of the window or scrolling region, either as a
71       result of a newline action on the bottom line, or typing the last char‐
72       acter of the last line.  If disabled, (bf is FALSE), the cursor is left
73       on the bottom line.  If enabled, (bf is TRUE), the window  is  scrolled
74       up one line (Note that to get the physical scrolling effect on the ter‐
75       minal, it is also necessary to call idlok).
76
77   setscrreg/wsetscrreg
78       The setscrreg and wsetscrreg routines allow the application  programmer
79       to set a software scrolling region in a window.  The top and bot param‐
80       eters are the line  numbers  of  the  top  and  bottom  margin  of  the
81       scrolling region.  (Line 0 is the top line of the window.)  If this op‐
82       tion and scrollok are enabled, an attempt to move off the bottom margin
83       line causes all lines in the scrolling region to scroll one line in the
84       direction of the first line.  Only the text of the window is  scrolled.
85       (Note  that this has nothing to do with the use of a physical scrolling
86       region capability in the terminal, like that in the VT100.  If idlok is
87       enabled and the terminal has either a scrolling region or insert/delete
88       line capability, they will probably be used by the output routines.)
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RETURN VALUE

91       The functions setscrreg and wsetscrreg return OK upon success  and  ERR
92       upon  failure.  All other routines that return an integer always return
93       OK.
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95       X/Open Curses does not define any error conditions.
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97       In this implementation,
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99       •   those functions that have a window pointer will return an error  if
100           the window pointer is null
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102wsetscrreg  returns  an error if the scrolling region limits extend
103           outside the window.
104
105       X/Open does not define any error conditions.  This  implementation  re‐
106       turns an error if the window pointer is null.
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PORTABILITY

109       These functions are described in the XSI Curses standard, Issue 4.
110
111       From the outset, ncurses used nl/nonl to control the conversion of new‐
112       lines to carriage return/line-feed on output as  well  as  input.   XSI
113       Curses  documents only the use of these functions for input.  This dif‐
114       ference arose from converting the  pcurses  source  (which  used  ioctl
115       calls  with  the sgttyb structure) to termios (i.e., the POSIX terminal
116       interface).  In the former, both input and output were controlled via a
117       single  option  CRMOD,  while the latter separates these features.  Be‐
118       cause that conversion interferes with output optimization, nl/nonl were
119       amended after ncurses 6.2 to eliminate their effect on output.
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121       Some  historic  curses implementations had, as an undocumented feature,
122       the ability to do the equivalent of clearok(..., 1)  by  saying  touch‐
123       win(stdscr) or clear(stdscr).  This will not work under ncurses.
124
125       Earlier  System  V  curses implementations specified that with scrollok
126       enabled, any window modification triggering  a  scroll  also  forced  a
127       physical refresh.  XSI Curses does not require this, and ncurses avoids
128       doing it to perform better  vertical-motion  optimization  at  wrefresh
129       time.
130
131       The XSI Curses standard does not mention that the cursor should be made
132       invisible as a side-effect of leaveok.  SVr4 curses documentation  does
133       this,  but  the code does not.  Use curs_set to make the cursor invisi‐
134       ble.
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NOTES

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

144       curses(3X), curs_addch(3X), curs_clear(3X), curs_initscr(3X),
145       curs_scroll(3X), curs_refresh(3X), curs_variables(3X).
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149                                                              curs_outopts(3X)
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