# curs_clear 3x

    curs_clear(3x)                                           curs_clear(3x)

## NAME

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

## SYNOPSIS

           # 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);

## DESCRIPTION

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

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

           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 erased.

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

           Blanks created by erasure have the current background ren-
           dition (as set by wbkgdset) merged into them.

## RETURN VALUE

           All routines return the integer OK on success and  ERR  on
           failure.   The SVr4.0 manual says "or a non-negative inte-
           ger if immedok is set", but this appears to be an error.

           X/Open defines no error conditions.  In  this  implementa-
           tion, functions using a window pointer parameter return an
           error if it is null.

## NOTES

           Note that erase, werase, clear, wclear, clrtobot, and clr-
           toeol may be macros.

## PORTABILITY

           These  functions are described in the XSI Curses standard,
           Issue 4.  The standard specifies that they return  ERR  on
           failure, but specifies no error conditions.

           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.

           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  implemen-
           tations, 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 de-
           rived window.  If you do not want to clear the screen dur-
           ing the next wrefresh, use werase instead.

## SEE ALSO

           curses(3x), curs_outopts(3x), curs_refresh(3x), curs_vari-
           ables(3x)

                                                             curs_clear(3x)