clear(3x) — Linux manual page


curs_clear(3X)                                                curs_clear(3X)

NAME         top

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

SYNOPSIS         top

       # 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         top

       The erase and werase routines copy blanks to every position 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 rendition (as
       set by wbkgdset) merged into them.

RETURN VALUE         top

       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

NOTES         top

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

PORTABILITY         top

       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
       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

SEE ALSO         top

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

COLOPHON         top

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