curs_clear 3x 2024-01-05 ncurses 6.4 Library calls

curs_clear(3x)                   Library calls                  curs_clear(3x)


       erase,  werase, clear, wclear, clrtobot, wclrtobot, clrtoeol, wclrtoeol
       - clear all or part of a curses window


       #include <curses.h>

       int erase(void);
       int werase(WINDOW *win);

       int clear(void);
       int wclear(WINDOW *win);

       int clrtobot(void);
       int wclrtobot(WINDOW *win);

       int clrtoeol(void);
       int wclrtoeol(WINDOW *win);


erase, werase

       The erase and werase routines copy blanks  to  every  position  in  the
       window, clearing the screen.

       Blanks created by erasure have the current background rendition (as set
       by wbkgdset(3x)) merged into them.

clear, wclear

       The clear and wclear routines are like erase and werase, but they  also
       call  clearok(3x), so that the screen is cleared completely on the next
       call to wrefresh for that window and repainted from scratch.

clrtobot, wclrtobot

       The clrtobot and wclrtobot routines erase from the cursor to the end of
       screen.   That is, they erase all lines below the cursor in the window.
       Also, the current line to  the  right  of  the  cursor,  inclusive,  is

clrtoeol, wclrtoeol

       The clrtoeol and wclrtoeol routines erase the current line to the right
       of the cursor, inclusive, to the end of the current line.


       All routines return the integer OK on success and ERR on failure.

       X/Open defines no error conditions.  In this implementation,

       o   functions using a window pointer parameter return an error if it is

       o   wclrtoeol returns an error if the cursor position is about to wrap.


       Note  that  erase, werase, clear, wclear, clrtobot, and clrtoeol may be


       These functions are described in the XSI Curses standard, Issue 4.

       The SVr4.0 manual says that these functions could  return  "or  a  non-
       negative  integer  if immedok is set", referring to the return-value of
       wrefresh.  In that implementation, wrefresh would return a count of the
       number of characters written to the terminal.

       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.

       This  implementation,  and  others  such  as  Solaris, sets the current
       position to 0,0 after erasing via werase and wclear.  That fact is  not
       documented   in   other   implementations,  and  may  not  be  true  of
       implementations which were not derived from SVr4 source.

       Not obvious from the description, most implementations clear the screen
       after  wclear  even  for  a subwindow or derived window.  If you do not
       want to clear the screen during the next wrefresh, use werase instead.


       curses(3x), curs_outopts(3x), curs_refresh(3x), curs_variables(3x)

ncurses 6.4                       2024-01-05                    curs_clear(3x)