# curs_clear 3x 2025-01-18 ncurses 6.6 Library calls

    curs_clear(3x)                   Library calls                  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

### 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
           erased.

### 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.

## RETURN VALUE

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

           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.

## NOTES

           erase, werase, clear, wclear, clrtobot, and clrtoeol may be implemented
           as macros.

## PORTABILITY

           X/Open Curses Issue 4 describes these functions.  It specifies no error
           conditions for them.

           SVr4  documentation  says  that  these  functions  return OK "or a non-
           negative integer if immedok() is set", referring to  the  return  value
           from  wrefresh,  which in SVr4 returns a count of characters written to
           the window if its immedok property is set; in ncurses, it does not.

           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.

## SEE ALSO

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

    ncurses 6.6                       2025-01-18                    curs_clear(3x)