curs_clear 3x 2024-05-25 ncurses 6.5 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 ERR if it is null

       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 X/Open Curses, 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 6.5                       2024-05-25                    curs_clear(3x)