1curs_outopts(3X) curs_outopts(3X)
2
6 clearok, idlok, idcok, immedok, leaveok, setscrreg, wsetscrreg,
7 scrollok, nl, nonl - curses output options
8
10 #include <curses.h>
11 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
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(3X).
27 clearok
29 If clearok is called with TRUE as argument, the next call to wrefresh
30 with this window will clear the screen completely and redraw the entire
31 screen from scratch. This is useful when the contents of the screen
32 are uncertain, or in some cases for a more pleasing visual effect. If
33 the win argument to clearok is the global variable curscr, the next
34 call to wrefresh with any window causes the screen to be cleared and
35 repainted from scratch.
36 idlok
38 If idlok is called with TRUE as second argument, curses considers using
39 the hardware insert/delete line feature of terminals so equipped.
40 Calling idlok with FALSE as second argument disables use of line inser‐
41 tion and deletion. This option should be enabled only if the applica‐
42 tion needs insert/delete line, for example, for a screen editor. It is
43 disabled by default because insert/delete line tends to be visually an‐
44 noying when used in applications where it is not really needed. If in‐
45 sert/delete line cannot be used, curses redraws the changed portions of
46 all lines.
47 idcok
49 If idcok is called with FALSE as second argument, curses no longer con‐
50 siders using the hardware insert/delete character feature of terminals
51 so equipped. Use of character insert/delete is enabled by default.
52 Calling idcok with TRUE as second argument re-enables use of character
53 insertion and deletion.
54 immedok
56 If immedok is called with TRUE as argument, any change in the window
57 image, such as the ones caused by waddch, wclrtobot, wscrl, etc., auto‐
58 matically cause a call to wrefresh. However, it may degrade perfor‐
59 mance considerably, due to repeated calls to wrefresh. It is disabled
60 by default.
61 leaveok
63 Normally, the hardware cursor is left at the location of the window
64 cursor being refreshed. The leaveok option allows the cursor to be
65 left wherever the update happens to leave it. It is useful for appli‐
66 cations where the cursor is not used, since it reduces the need for
67 cursor motions.
68 setscrreg
70 The setscrreg and wsetscrreg routines allow the application programmer
71 to set a software scrolling region in a window. The top and bot param‐
72 eters are the line numbers of the top and bottom margin of the
73 scrolling region. (Line 0 is the top line of the window.) If this op‐
74 tion and scrollok are enabled, an attempt to move off the bottom margin
75 line causes all lines in the scrolling region to scroll one line in the
76 direction of the first line. Only the text of the window is scrolled.
77 (Note that this has nothing to do with the use of a physical scrolling
78 region capability in the terminal, like that in the VT100. If idlok is
79 enabled and the terminal has either a scrolling region or insert/delete
80 line capability, they will probably be used by the output routines.)
81 scrollok
83 The scrollok option controls what happens when the cursor of a window
84 is moved off the edge of the window or scrolling region, either as a
85 result of a newline action on the bottom line, or typing the last char‐
86 acter of the last line. If disabled, (bf is FALSE), the cursor is left
87 on the bottom line. If enabled, (bf is TRUE), the window is scrolled
88 up one line (Note that to get the physical scrolling effect on the ter‐
89 minal, it is also necessary to call idlok).
90 nl, nonl
92 The nl and nonl routines control whether the underlying display device
93 translates the return key into newline on input, and whether it trans‐
94 lates newline into return and line-feed on output (in either case, the
95 call addch('\n') does the equivalent of return and line feed on the
96 virtual screen). Initially, these translations do occur. If you dis‐
97 able them using nonl, curses will be able to make better use of the
98 line-feed capability, resulting in faster cursor motion. Also, curses
99 will then be able to detect the return key.
100
102 The functions setscrreg and wsetscrreg return OK upon success and ERR
103 upon failure. All other routines that return an integer always return
104 OK.
105 X/Open Curses does not define any error conditions.
107 In this implementation, those functions that have a window pointer will
109 return an error if the window pointer is null.
110 wclrtoeol
112 returns an error if the cursor position is about to wrap.
113 wsetscrreg
115 returns an error if the scrolling region limits extend out‐
116 side the window.
117 X/Open does not define any error conditions. This implementation re‐
119 turns an error if the window pointer is null.
120
122 These functions are described in the XSI Curses standard, Issue 4.
123 The XSI Curses standard is ambiguous on the question of whether raw
125 should disable the CRLF translations controlled by nl and nonl. BSD
126 curses did turn off these translations; AT&T curses (at least as late
127 as SVr1) did not. We choose to do so, on the theory that a programmer
128 requesting raw input wants a clean (ideally 8-bit clean) connection
129 that the operating system will not alter.
130 Some historic curses implementations had, as an undocumented feature,
132 the ability to do the equivalent of clearok(..., 1) by saying touch‐
133 win(stdscr) or clear(stdscr). This will not work under ncurses.
134 Earlier System V curses implementations specified that with scrollok
136 enabled, any window modification triggering a scroll also forced a
137 physical refresh. XSI Curses does not require this, and ncurses avoids
138 doing it to perform better vertical-motion optimization at wrefresh
139 time.
140 The XSI Curses standard does not mention that the cursor should be made
142 invisible as a side-effect of leaveok. SVr4 curses documentation does
143 this, but the code does not. Use curs_set to make the cursor invisi‐
144 ble.
145
147 Note that clearok, leaveok, scrollok, idcok, nl, nonl and setscrreg may
148 be macros.
149 The immedok routine is useful for windows that are used as terminal em‐
151 ulators.
152
154 curses(3X), curs_addch(3X), curs_clear(3X), curs_initscr(3X),
155 curs_scroll(3X), curs_refresh(3X), curs_variables(3X).
156 curs_outopts(3X)