- These routines set options that change the style of output
- within curses. All options are initially FALSE, unless
- otherwise stated. It is not necessary to turn these op-
- tions off before calling endwin.
-
- If clearok is called with TRUE as argument, the next call
- to wrefresh with this window will clear the screen com-
- pletely and redraw the entire screen from scratch. This
- is useful when the contents of the screen are uncertain,
- or in some cases for a more pleasing visual effect. If
- the win argument to clearok is the global variable curscr,
- the next call to wrefresh with any window causes the
- screen to be cleared and repainted from scratch.
-
- If idlok is called with TRUE as second argument, curses
- considers using the hardware insert/delete line feature of
- terminals so equipped. Calling idlok with FALSE as second
- argument disables use of line insertion and deletion.
- This option should be enabled only if the application
- needs insert/delete line, for example, for a screen edi-
- tor. It is disabled by default because insert/delete line
- tends to be visually annoying when used in applications
- where it is not really needed. If insert/delete line can-
- not be used, curses redraws the changed portions of all
- lines.
-
- If idcok is called with FALSE as second argument, curses
- no longer considers using the hardware insert/delete char-
- acter feature of terminals so equipped. Use of character
- insert/delete is enabled by default. Calling idcok with
- TRUE as second argument re-enables use of character inser-
- tion and deletion.
-
- If immedok is called with TRUEasargument, any change in
- the window image, such as the ones caused by waddch,wclr-
- tobot,wscrl, etc., automatically cause a call to wre-
- fresh. However, it may degrade performance considerably,
- due to repeated calls to wrefresh. It is disabled by de-
- fault.
-
- Normally, the hardware cursor is left at the location of
- the window cursor being refreshed. The leaveok option al-
- lows the cursor to be left wherever the update happens to
- leave it. It is useful for applications where the cursor
- is not used, since it reduces the need for cursor motions.
-
- The setscrreg and wsetscrreg routines allow the applica-
- tion programmer to set a software scrolling region in a
- window. The top and bot parameters are the line numbers
- of the top and bottom margin of the scrolling region.
- (Line 0 is the top line of the window.) If this option
- and scrollok are enabled, an attempt to move off the bot-
- tom margin line causes all lines in the scrolling region
- to scroll one line in the direction of the first line.
- Only the text of the window is scrolled. (Note that this
- has nothing to do with the use of a physical scrolling re-
- gion capability in the terminal, like that in the VT100.
- If idlok is enabled and the terminal has either a
- scrolling region or insert/delete line capability, they
- will probably be used by the output routines.)
-
- The scrollok option controls what happens when the cursor
- of a window is moved off the edge of the window or
- scrolling region, either as a result of a newline action
- on the bottom line, or typing the last character of the
- last line. If disabled, (bf is FALSE), the cursor is left
- on the bottom line. If enabled, (bf is TRUE), the window
- is scrolled up one line (Note that to get the physical
- scrolling effect on the terminal, it is also necessary to
- call idlok).
-
- The nl and nonl routines control whether the underlying
- display device translates the return key into newline on
- input, and whether it translates newline into return and
- line-feed on output (in either case, the call addch('\n')
- does the equivalent of return and line feed on the virtual
- screen). Initially, these translations do occur. If you
- disable them using nonl, curses will be able to make bet-
- ter use of the line-feed capability, resulting in faster
- cursor motion. Also, curses will then be able to detect
- the return key.
+
+ These routines set options that change the style of output within
+ curses. All options are initially FALSE, unless otherwise stated. It
+ is not necessary to turn these options off before calling endwin(3x).
+
+
+
+ If clearok is called with TRUE as argument, the next call to wrefresh
+ with this window will clear the screen completely and redraw the entire
+ screen from scratch. This is useful when the contents of the screen
+ are uncertain, or in some cases for a more pleasing visual effect. If
+ the win argument to clearok is the global variable curscr, the next
+ call to wrefresh with any window causes the screen to be cleared and
+ repainted from scratch.
+
+
+
+ If idlok is called with TRUE as second argument, curses considers using
+ the hardware insert/delete line feature of terminals so equipped.
+ Calling idlok with FALSE as second argument disables use of line
+ insertion and deletion. This option should be enabled only if the
+ application needs insert/delete line, for example, for a screen editor.
+ It is disabled by default because insert/delete line tends to be
+ visually annoying when used in applications where it is not really
+ needed. If insert/delete line cannot be used, curses redraws the
+ changed portions of all lines.
+
+
+
+ If idcok is called with FALSE as second argument, curses no longer
+ considers using the hardware insert/delete character feature of
+ terminals so equipped. Use of character insert/delete is enabled by
+ default. Calling idcok with TRUE as second argument re-enables use of
+ character insertion and deletion.
-
- The functions setscrreg and wsetscrreg return OK upon suc-
- cess and ERR upon failure. All other routines that return
- an integer always return OK.
+
+ If immedok is called with TRUE as second argument, any change in the
+ window image, such as the ones caused by waddch,wclrtobot,wscrl,
+ etc., automatically causes a call to wrefresh. However, it may degrade
+ performance considerably, due to repeated calls to wrefresh. Calling
+ immedok with FALSE as second argument restores the default behavior,
+ i.e., deferring screen updates until a refresh is needed.
+
- X/Open does not define any error conditions.
+
+ Normally, the hardware cursor is left at the location of the window
+ cursor being refreshed. The leaveok option allows the cursor to be
+ left wherever the update happens to leave it. It is useful for
+ applications where the cursor is not used, since it reduces the need
+ for cursor motions.
- In this implementation, those functions that have a window
- pointer will return an error if the window pointer is
- null.
- wclrtoeol
- returns an error if the cursor position is
- about to wrap.
+
+ The scrollok option controls what happens when the cursor of a window
+ is moved off the edge of the window or scrolling region, either as a
+ result of a newline action on the bottom line, or typing the last
+ character of the last line. If disabled, (bf is FALSE), the cursor is
+ left on the bottom line. If enabled, (bf is TRUE), the window is
+ scrolled up one line (Note that to get the physical scrolling effect on
+ the terminal, it is also necessary to call idlok).
- wsetscrreg
- returns an error if the scrolling region lim-
- its extend outside the window.
- X/Open does not define any error conditions. This imple-
- mentation returns an error if the window pointer is null.
+
+ The setscrreg and wsetscrreg routines allow the application programmer
+ to set a software scrolling region in a window. The top and bot
+ parameters are the line numbers of the top and bottom margin of the
+ scrolling region. (Line 0 is the top line of the window.) If this
+ option and scrollok are enabled, an attempt to move off the bottom
+ margin line causes all lines in the scrolling region to scroll one line
+ in the direction of the first line. Only the text of the window is
+ scrolled. (Note that this has nothing to do with the use of a physical
+ scrolling region capability in the terminal, like that in the VT100.
+ If idlok is enabled and the terminal has either a scrolling region or
+ insert/delete line capability, they will probably be used by the output
+ routines.)
-
- These functions are described in the XSI Curses standard,
- Issue 4.
-
- The XSI Curses standard is ambiguous on the question of
- whether raw() should disable the CRLF translations con-
- trolled by nl() and nonl(). BSD curses did turn off these
- translations; AT&T curses (at least as late as SVr1) did
- not. We choose to do so, on the theory that a programmer
- requesting raw input wants a clean (ideally 8-bit clean)
- connection that the operating system will not alter.
-
- Some historic curses implementations had, as an undocu-
- mented feature, the ability to do the equivalent of
- clearok(...,1) by saying touchwin(stdscr) or clear(std-
- scr). This will not work under ncurses.
-
- Earlier System V curses implementations specified that
- with scrollok enabled, any window modification triggering
- a scroll also forced a physical refresh. XSI Curses does
- not require this, and ncurses avoids doing it to perform
- better vertical-motion optimization at wrefresh time.
-
- The XSI Curses standard does not mention that the cursor
- should be made invisible as a side-effect of leaveok.
- SVr4 curses documentation does this, but the code does
- not. Use curs_set to make the cursor invisible.
+
+ The functions setscrreg and wsetscrreg return OK upon success and ERR
+ upon failure. All other routines that return an integer always return
+ OK.
+ X/Open Curses does not define any error conditions.
-
- Note that clearok, leaveok, scrollok, idcok, nl, nonl and
- setscrreg may be macros.
+ In this implementation,
- The immedok routine is useful for windows that are used as
- terminal emulators.
+ o those functions that have a window pointer will return an error if
+ the window pointer is null
+ owsetscrreg returns an error if the scrolling region limits extend
+ outside the window.
-
+ These functions are described in the XSI Curses standard, Issue 4.
+
+ From the outset, ncurses used nl/nonl to control the conversion of
+ newlines to carriage return/line-feed on output as well as input. XSI
+ Curses documents only the use of these functions for input. This
+ difference arose from converting the pcurses source (which used ioctl
+ calls with the sgttyb structure) to termios (i.e., the POSIX terminal
+ interface). In the former, both input and output were controlled via a
+ single option CRMOD, while the latter separates these features.
+ Because that conversion interferes with output optimization, nl/nonl
+ were amended after ncurses 6.2 to eliminate their effect on output.
+ Some historic curses implementations had, as an undocumented feature,
+ the ability to do the equivalent of clearok(...,1) by saying
+ touchwin(stdscr) or clear(stdscr). This will not work under ncurses.
+ Earlier System V curses implementations specified that with scrollok
+ enabled, any window modification triggering a scroll also forced a
+ physical refresh. XSI Curses does not require this, and ncurses avoids
+ doing it to perform better vertical-motion optimization at wrefresh
+ time.
- curs_outopts(3x)
+ The XSI Curses standard does not mention that the cursor should be made
+ invisible as a side-effect of leaveok. SVr4 curses documentation does
+ this, but the code does not. Use curs_set to make the cursor
+ invisible.
+
+
+
+ Note that clearok, leaveok, scrollok, idcok, and setscrreg may be
+ macros.
+
+ The immedok routine is useful for windows that are used as terminal
+ emulators.
+
+
+