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29 * @Id: curs_clear.3x,v 1.15 2016/10/15 17:02:31 tom Exp @
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41 <H1 class="no-header">curs_clear 3x</H1>
43 <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG> <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>
48 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
49 <STRONG>erase</STRONG>, <STRONG>werase</STRONG>, <STRONG>clear</STRONG>, <STRONG>wclear</STRONG>, <STRONG>clrtobot</STRONG>, <STRONG>wclrtobot</STRONG>, <STRONG>clrtoeol</STRONG>, <STRONG>wclrtoeol</STRONG>
50 - clear all or part of a <STRONG>curses</STRONG> window
53 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
54 <STRONG>#</STRONG> <STRONG>include</STRONG> <STRONG><curses.h></STRONG>
56 <STRONG>int</STRONG> <STRONG>erase(void);</STRONG>
57 <STRONG>int</STRONG> <STRONG>werase(WINDOW</STRONG> <STRONG>*win);</STRONG>
58 <STRONG>int</STRONG> <STRONG>clear(void);</STRONG>
59 <STRONG>int</STRONG> <STRONG>wclear(WINDOW</STRONG> <STRONG>*win);</STRONG>
60 <STRONG>int</STRONG> <STRONG>clrtobot(void);</STRONG>
61 <STRONG>int</STRONG> <STRONG>wclrtobot(WINDOW</STRONG> <STRONG>*win);</STRONG>
62 <STRONG>int</STRONG> <STRONG>clrtoeol(void);</STRONG>
63 <STRONG>int</STRONG> <STRONG>wclrtoeol(WINDOW</STRONG> <STRONG>*win);</STRONG>
66 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
67 The <STRONG>erase</STRONG> and <STRONG>werase</STRONG> routines copy blanks to every position in the win-
68 dow, clearing the screen.
70 The <STRONG>clear</STRONG> and <STRONG>wclear</STRONG> routines are like <STRONG>erase</STRONG> and <STRONG>werase</STRONG>, but they also
71 call <STRONG>clearok</STRONG>, so that the screen is cleared completely on the next call
72 to <STRONG>wrefresh</STRONG> for that window and repainted from scratch.
74 The <STRONG>clrtobot</STRONG> and <STRONG>wclrtobot</STRONG> routines erase from the cursor to the end of
75 screen. That is, they erase all lines below the cursor in the window.
76 Also, the current line to the right of the cursor, inclusive, is
79 The <STRONG>clrtoeol</STRONG> and <STRONG>wclrtoeol</STRONG> routines erase the current line to the right
80 of the cursor, inclusive, to the end of the current line.
82 Blanks created by erasure have the current background rendition (as set
83 by <STRONG>wbkgdset</STRONG>) merged into them.
86 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
87 All routines return the integer <STRONG>OK</STRONG> on success and <STRONG>ERR</STRONG> on failure. The
88 SVr4.0 manual says "or a non-negative integer if <STRONG>immedok</STRONG> is set", but
89 this appears to be an error.
91 X/Open defines no error conditions. In this implementation, functions
92 using a window pointer parameter return an error if it is null.
95 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
96 Note that <STRONG>erase</STRONG>, <STRONG>werase</STRONG>, <STRONG>clear</STRONG>, <STRONG>wclear</STRONG>, <STRONG>clrtobot</STRONG>, and <STRONG>clrtoeol</STRONG> may be
100 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
101 These functions are described in the XSI Curses standard, Issue 4. The
102 standard specifies that they return <STRONG>ERR</STRONG> on failure, but specifies no
105 Some historic curses implementations had, as an undocumented feature,
106 the ability to do the equivalent of <STRONG>clearok(...,</STRONG> <STRONG>1)</STRONG> by saying <STRONG>touch-</STRONG>
107 <STRONG>win(stdscr)</STRONG> or <STRONG>clear(stdscr)</STRONG>. This will not work under ncurses.
109 This implementation, and others such as Solaris, sets the current posi-
110 tion to 0,0 after erasing via <STRONG>werase</STRONG> and <STRONG>wclear</STRONG>. That fact is not doc-
111 umented in other implementations, and may not be true of implementa-
112 tions which were not derived from SVr4 source.
114 Not obvious from the description, most implementations clear the screen
115 after <STRONG>wclear</STRONG> even for a subwindow or derived window. If you do not
116 want to clear the screen during the next <STRONG>wrefresh</STRONG>, use <STRONG>werase</STRONG> instead.
119 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
120 <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_outopts.3x.html">curs_outopts(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>
124 <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>
128 <li><a href="#h2-NAME">NAME</a></li>
129 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
130 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
131 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
132 <li><a href="#h2-NOTES">NOTES</a></li>
133 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
134 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>