erase, werase, clear, wclear, clrtobot, wclrtobot,
clrtoeol, wclrtoeol - clear all or part of a curses window
# include <curses.h>
int werase(WINDOW *win);
int wclear(WINDOW *win);
int wclrtobot(WINDOW *win);
int wclrtoeol(WINDOW *win);
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
Blanks created by erasure have the current background ren-
dition (as set by wbkgdset) merged into them.
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.
Note that erase, werase, clear, wclear, clrtobot, and clr-
toeol may be macros.
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.
curses(3x), curs_outopts(3x), curs_refresh(3x), curs_vari-