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+ * Copyright (c) 1998-2007,2010 Free Software Foundation, Inc. *
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- * @Id: curs_clear.3x,v 1.10 2005/10/01 19:34:43 tom Exp @
+ * @Id: curs_clear.3x,v 1.12 2010/07/31 16:12:01 tom Exp @
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</PRE>
<H2>DESCRIPTION</H2><PRE>
- The <STRONG>erase</STRONG> and <STRONG>werase</STRONG> routines copy blanks to every posi-
+ The <STRONG>erase</STRONG> and <STRONG>werase</STRONG> routines copy blanks to every posi-
tion in the window, clearing the screen.
- The <STRONG>clear</STRONG> and <STRONG>wclear</STRONG> routines are like <STRONG>erase</STRONG> and <STRONG>werase</STRONG>,
- but they also call <STRONG>clearok</STRONG>, so that the screen is cleared
- completely on the next call to <STRONG>wrefresh</STRONG> for that window
+ The <STRONG>clear</STRONG> and <STRONG>wclear</STRONG> routines are like <STRONG>erase</STRONG> and <STRONG>werase</STRONG>,
+ but they also call <STRONG>clearok</STRONG>, so that the screen is cleared
+ completely on the next call to <STRONG>wrefresh</STRONG> for that window
and repainted from scratch.
- The <STRONG>clrtobot</STRONG> and <STRONG>wclrtobot</STRONG> routines erase from the cursor
+ The <STRONG>clrtobot</STRONG> and <STRONG>wclrtobot</STRONG> 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
+ the cursor in the window. Also, the current line to the
right of the cursor, inclusive, is erased.
The <STRONG>clrtoeol</STRONG> and <STRONG>wclrtoeol</STRONG> routines erase the current line
- to the right of the cursor, inclusive, to the end of the
+ to the right of the cursor, inclusive, to the end of the
current line.
Blanks created by erasure have the current background ren-
</PRE>
<H2>RETURN VALUE</H2><PRE>
- All routines return the integer <STRONG>OK</STRONG> on success and <STRONG>ERR</STRONG> on
- failure. The SVr4.0 manual says "or a non-negative inte-
+ All routines return the integer <STRONG>OK</STRONG> on success and <STRONG>ERR</STRONG> on
+ failure. The SVr4.0 manual says "or a non-negative inte-
ger if <STRONG>immedok</STRONG> is set", but this appears to be an error.
- X/Open defines no error conditions. In this implementa-
+ X/Open defines no error conditions. In this implementa-
tion, functions using a window pointer parameter return an
error if it is null.
</PRE>
<H2>PORTABILITY</H2><PRE>
- These functions are described in the XSI Curses standard,
- Issue 4. The standard specifies that they return <STRONG>ERR</STRONG> on
+ These functions are described in the XSI Curses standard,
+ Issue 4. The standard specifies that they return <STRONG>ERR</STRONG> on
failure, but specifies no error conditions.
- Some historic curses implementations had, as an undocu-
- mented feature, the ability to do the equivalent of
- <STRONG>clearok(...,</STRONG> <STRONG>1)</STRONG> by saying <STRONG>touchwin(stdscr)</STRONG> or <STRONG>clear(std-</STRONG>
+ Some historic curses implementations had, as an undocu-
+ mented feature, the ability to do the equivalent of
+ <STRONG>clearok(...,</STRONG> <STRONG>1)</STRONG> by saying <STRONG>touchwin(stdscr)</STRONG> or <STRONG>clear(std-</STRONG>
<STRONG>scr)</STRONG>. This will not work under ncurses.
- This implementation, and others such as Solaris, sets the
- current position to 0,0 after erasing via <STRONG>werase()</STRONG> and
- <STRONG>wclear()</STRONG>. That fact is not documented in other implemen-
+ This implementation, and others such as Solaris, sets the
+ current position to 0,0 after erasing via <STRONG>werase()</STRONG> and
+ <STRONG>wclear()</STRONG>. 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 <STRONG>wclear</STRONG> even for a subwindow or de-
+ rived window. If you do not want to clear the screen dur-
+ ing the next <STRONG>wrefresh</STRONG>, use <STRONG>werase</STRONG> instead.
+
</PRE>
<H2>SEE ALSO</H2><PRE>
projects / ncurses.git / blobdiff