# curs_outopts

## NAME



           **clearok** , **idlok** , **idcok** , **immedok** , **leaveok** , **setscrreg** , **wsetscrreg** ,
           **scrollok** - **curses** output options
    


## SYNOPSIS



           **#include <curses.h>**
    
           **int clearok(WINDOW ***_win_**, bool** _bf_**);**
           **int idlok(WINDOW ***_win_**, bool** _bf_**);**
           **void idcok(WINDOW ***_win_**, bool** _bf_**);**
           **void immedok(WINDOW ***_win_**, bool** _bf_**);**
           **int leaveok(WINDOW ***_win_**, bool** _bf_**);**
           **int scrollok(WINDOW ***_win_**, bool** _bf_**);**
    
           **int setscrreg(int** _top_**, int** _bot_**);**
           **int wsetscrreg(WINDOW ***_win_**, int** _top_**, int** _bot_**);**
    


## DESCRIPTION



           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  **end‐**
           **win**(3X).
    
       **clearok**
           If  **clearok** is called with **TRUE** as argument, the next call to **wre‐**
           **fresh** 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 vari‐
           able **curscr** , the next call to **wrefresh** with any window causes  the
           screen to be cleared and repainted from scratch.
    
       **idlok**
           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.
    
       **idcok**
           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.
    
       **immedok**
           If **immedok** is called with **TRUE as argument** , any change in the win‐
           dow image, such as the ones caused by  **waddch,  wclrtobot,  wscrl** ,
           etc., automatically cause a call to **wrefresh**.  However, it may de‐
           grade performance considerably, due to repeated calls to **wrefresh**.
           It is disabled by default.
    
       **leaveok**
           Normally,  the hardware cursor is left at the location of the win‐
           dow 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.
    
       **scrollok**
           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 typ‐
           ing  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**).
    
       **setscrreg/wsetscrreg**
           The  **setscrreg** and **wsetscrreg** routines allow the application pro‐
           grammer to set a software scrolling region in a window.   The  _top_
           and _bot_ parameters are the line numbers of the top and bottom mar‐
           gin  of the scrolling region.  (Line 0 is the top line of the win‐
           dow.)  If this option and **scrollok** are enabled, an attempt to move
           off the bottom margin line causes all lines in the  scrolling  re‐
           gion  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 capa‐
           bility, they will probably be used by the output routines.)
    


## RETURN VALUE



           The functions **setscrreg** and **wsetscrreg** return **OK** upon success  and
           **ERR** upon  failure.  All other routines that return an integer al‐
           ways return **OK**.
    
           X/Open Curses does not define any error conditions.
    
           In this implementation,
    
           •   those functions that have a window pointer will return an er‐
               ror if the window pointer is null
    
           •   **wsetscrreg** returns an error if the scrolling region limits ex‐
               tend outside the window.
    
           X/Open does not define any error conditions.  This implementation
           returns an error if the window pointer is null.
    


## PORTABILITY



           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 sepa‐
           rates 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 fea‐
           ture, the ability to do the equivalent of **clearok(..., 1)** by say‐
           ing **touchwin(stdscr)** or **clear(stdscr)**.  This will not work under
           ncurses.
    
           Earlier System V curses implementations specified that with **scrol‐**
           **lok** 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 opti‐
           mization 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 documen‐
           tation does this, but the code does not.  Use **curs_set** to make the
           cursor invisible.
    


## NOTES



           Note that **clearok** , **leaveok** , **scrollok** , **idcok** , and **setscrreg** may be
           macros.
    
           The **immedok** routine is useful for windows that are used as termi‐
           nal emulators.
    


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