- 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 win-
+ dow, 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. The SVr4.0 manual
- says "or a non-negative integer 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.
-
-
NOTES
- Note that erase, werase, clear, wclear, clrtobot, and clr-
- toeol may be macros.
+
+ The clrtoeol and wclrtoeol routines erase the current line to the right
+ of the cursor, inclusive, to the end of the current line.
-
-
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.
+
+ All routines return the integer OK on success and ERR on failure.
- 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.
+ X/Open defines no error conditions. In this implementation,
+ o functions using a window pointer parameter return an error if it is
+ null
-
+ 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.
+
+ The SVr4.0 manual says that these functions could return "a non-nega-
+ tive integer if immedok(3x) 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 touch-
+ win(stdscr) or clear(stdscr). This will not work under ncurses.
+
+ This implementation, and others such as Solaris, sets the current posi-
+ tion to 0,0 after erasing via werase and wclear. That fact is not doc-
+ umented in other implementations, and may not be true of implementa-
+ tions 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.
+
+
+