- 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 erase and werase routines copy blanks to every position in the
+ window, clearing the screen.
- 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.
+ Blanks created by erasure have the current background rendition (as set
+ by wbkgdset(3x)) merged into them.
- 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.
+
+ The clear and wclear routines are like erase and werase, but they also
+ call clearok(3x), so that the screen is cleared completely on the next
+ call to wrefresh for that window and repainted from scratch.
-
-
RETURN VALUE
- 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.
+
+ 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.
- X/Open defines no error conditions. In this implementa-
- tion, functions using a window pointer parameter return an
- error if it is null.
+
+ All routines return the integer OK on success and ERR on failure.
-
-
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.
+ X/Open defines no error conditions. In this implementation,
- 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.
+ o functions using a window pointer parameter return an error if it is
+ null
- 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.
+ owclrtoeol returns an error if the cursor position is about to wrap.
- 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.
+
+ These functions are described in X/Open Curses, Issue 4.
+
+ The SVr4.0 manual says that these functions could return "or 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.
+
+
+