curs_clear(3x) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | PORTABILITY | SEE ALSO | COLOPHON

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.

       X/Open defines no error conditions.  In this implementation,

       •   functions using a window pointer parameter return an error if
           it is null

       •   wclrtoeol returns an error if the cursor position is about to
           wrap.

NOTES         top

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

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.

       The SVr4.0 manual says that these functions could return "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.

SEE ALSO         top

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

COLOPHON         top

       This page is part of the ncurses (new curses) project.
       Information about the project can be found at 
       ⟨https://www.gnu.org/software/ncurses/ncurses.html⟩.  If you have
       a bug report for this manual page, send it to
       bug-ncurses-request@gnu.org.  This page was obtained from the
       project's upstream Git mirror of the CVS repository
       ⟨git://ncurses.scripts.mit.edu/ncurses.git⟩ on 2021-06-20.  (At
       that time, the date of the most recent commit that was found in
       the repository was 2021-05-23.)  If you discover any rendering
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       (which is not part of the original manual page), send a mail to
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                                                          curs_clear(3X)