- erase, werase, clear, wclear, clrtobot, wclrtobot, clr-
- toeol, wclrtoeol - clear all or part of a curses window
+ erase, werase, clear, wclear, clrtobot, wclrtobot,
+ clrtoeol, wclrtoeol - clear all or part of a curses window
- The erase and werase routines copy blanks to every posi-
+ 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
+ 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
+ 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
+ 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 ren-
- dition (as set by wbkgdset) merged into them.
+ dition (as set by wbkgdset) merged into them.
RETURN VALUE
- All routines return the integer OK. The SVr4.0 manual
- says "or a non-negative integer if immedok is set", but
- this appears to be an error.
+ 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.
NOTES
- Note that erase, werase, clear, wclear, clrtobot, and clr-
- toeol may be macros.
+ Note that erase, werase, clear, wclear, clrtobot, and clr-
+ toeol may be macros.
PORTABILITY
These functions are described in the XSI Curses standard,
- Issue 4. The standard specifies that they return ERR on
+ 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(stdscr). This will not work under ncurses.
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SEE ALSO
- curses(3x), curs_outopts(3x), curs_refresh(3x)
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+ 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.
+