|
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | PORTABILITY | SEE ALSO | COLOPHON |
curs_clear(3X) curs_clear(3X)
erase, werase, clear, wclear, clrtobot, wclrtobot, clrtoeol,
wclrtoeol - clear all or part of a curses window
# 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);
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.
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
null.
Note that erase, werase, clear, wclear, clrtobot, and clrtoeol 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 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.
curses(3X), curs_outopts(3X), curs_refresh(3X), curs_variables(3X)
This page is part of the ncurses (new curses) project. Information
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curs_clear(3X)