# 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 position in the win-
           dow, 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 rendition (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 integer if immedok is set", but
           this appears to be an error.

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

## NOTES

           Note  that  erase, werase, clear, wclear, clrtobot, and clrtoeol 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  undocumented  feature,
           the  ability  to  do the equivalent of clearok(..., 1) by saying touch-
           win(stdscr) or clear(stdscr).  This will not work under ncurses.

           This implementation, and others such as Solaris, sets the current posi-
           tion to 0,0 after erasing via werase and wclear.  That fact is not doc-
           umented in other implementations, and may not be  true  of  implementa-
           tions 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.

## SEE ALSO

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

                                                                    curs_clear(3x)