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 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, inclu-sive, inclusive,
sive, 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 nonnegative
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 parame-ter parameter
ter 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 equiva-lent equivalent
lent of clearok(..., 1) by saying touchwin(stdscr) or clear(stdscr). This will not work under ncurs-es. ncurses.
es.
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.
SEE ALSO
curses(3X), curs_outopts(3X), curs_refresh(3X)
curs_clear(3X)
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