db11128f8f5a352f82ec1b87faad5956fe9d4280
[ncurses.git] / doc / html / man / curs_clear.3x.html
1 <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
2 <!-- 
3   ****************************************************************************
4   * Copyright (c) 1998-2007,2010 Free Software Foundation, Inc.              *
5   *                                                                          *
6   * Permission is hereby granted, free of charge, to any person obtaining a  *
7   * copy of this software and associated documentation files (the            *
8   * "Software"), to deal in the Software without restriction, including      *
9   * without limitation the rights to use, copy, modify, merge, publish,      *
10   * distribute, distribute with modifications, sublicense, and/or sell       *
11   * copies of the Software, and to permit persons to whom the Software is    *
12   * furnished to do so, subject to the following conditions:                 *
13   *                                                                          *
14   * The above copyright notice and this permission notice shall be included  *
15   * in all copies or substantial portions of the Software.                   *
16   *                                                                          *
17   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
18   * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
19   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
20   * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
21   * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
22   * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
23   * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
24   *                                                                          *
25   * Except as contained in this notice, the name(s) of the above copyright   *
26   * holders shall not be used in advertising or otherwise to promote the     *
27   * sale, use or other dealings in this Software without prior written       *
28   * authorization.                                                           *
29   ****************************************************************************
30   * @Id: curs_clear.3x,v 1.12 2010/07/31 16:12:01 tom Exp @
31 -->
32 <HTML>
33 <HEAD>
34 <TITLE>curs_clear 3x</TITLE>
35 <link rev=made href="mailto:bug-ncurses@gnu.org">
36 <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
37 </HEAD>
38 <BODY>
39 <H1>curs_clear 3x</H1>
40 <HR>
41 <PRE>
42 <!-- Manpage converted by man2html 3.0.1 -->
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>
44
45
46
47
48 </PRE>
49 <H2>NAME</H2><PRE>
50        <STRONG>erase</STRONG>, <STRONG>werase</STRONG>, <STRONG>clear</STRONG>, <STRONG>wclear</STRONG>, <STRONG>clrtobot</STRONG>, <STRONG>wclrtobot</STRONG>,
51        <STRONG>clrtoeol</STRONG>, <STRONG>wclrtoeol</STRONG> - clear all or part of a <STRONG>curses</STRONG> window
52
53
54 </PRE>
55 <H2>SYNOPSIS</H2><PRE>
56        <STRONG>#</STRONG> <STRONG>include</STRONG> <STRONG>&lt;curses.h&gt;</STRONG>
57
58        <STRONG>int</STRONG> <STRONG>erase(void);</STRONG>
59        <STRONG>int</STRONG> <STRONG>werase(WINDOW</STRONG> <STRONG>*win);</STRONG>
60        <STRONG>int</STRONG> <STRONG>clear(void);</STRONG>
61        <STRONG>int</STRONG> <STRONG>wclear(WINDOW</STRONG> <STRONG>*win);</STRONG>
62        <STRONG>int</STRONG> <STRONG>clrtobot(void);</STRONG>
63        <STRONG>int</STRONG> <STRONG>wclrtobot(WINDOW</STRONG> <STRONG>*win);</STRONG>
64        <STRONG>int</STRONG> <STRONG>clrtoeol(void);</STRONG>
65        <STRONG>int</STRONG> <STRONG>wclrtoeol(WINDOW</STRONG> <STRONG>*win);</STRONG>
66
67
68 </PRE>
69 <H2>DESCRIPTION</H2><PRE>
70        The <STRONG>erase</STRONG> and <STRONG>werase</STRONG> routines copy blanks to  every  posi-
71        tion in the window, clearing the screen.
72
73        The  <STRONG>clear</STRONG>  and <STRONG>wclear</STRONG> routines are like <STRONG>erase</STRONG> and <STRONG>werase</STRONG>,
74        but they also call <STRONG>clearok</STRONG>, so that the screen is  cleared
75        completely  on  the  next call to <STRONG>wrefresh</STRONG> for that window
76        and repainted from scratch.
77
78        The <STRONG>clrtobot</STRONG> and <STRONG>wclrtobot</STRONG> routines erase from the  cursor
79        to the end of screen.  That is, they erase all lines below
80        the cursor in the window.  Also, the current line  to  the
81        right of the cursor, inclusive, is erased.
82
83        The <STRONG>clrtoeol</STRONG> and <STRONG>wclrtoeol</STRONG> routines erase the current line
84        to the right of the cursor, inclusive, to the end  of  the
85        current line.
86
87        Blanks created by erasure have the current background ren-
88        dition (as set by <STRONG>wbkgdset</STRONG>) merged into them.
89
90
91 </PRE>
92 <H2>RETURN VALUE</H2><PRE>
93        All routines return the integer <STRONG>OK</STRONG> on success and  <STRONG>ERR</STRONG>  on
94        failure.   The SVr4.0 manual says "or a non-negative inte-
95        ger if <STRONG>immedok</STRONG> is set", but this appears to be an error.
96
97        X/Open defines no error conditions.  In  this  implementa-
98        tion, functions using a window pointer parameter return an
99        error if it is null.
100
101
102 </PRE>
103 <H2>NOTES</H2><PRE>
104        Note that <STRONG>erase</STRONG>, <STRONG>werase</STRONG>, <STRONG>clear</STRONG>, <STRONG>wclear</STRONG>, <STRONG>clrtobot</STRONG>, and <STRONG>clr-</STRONG>
105        <STRONG>toeol</STRONG> may be macros.
106
107
108 </PRE>
109 <H2>PORTABILITY</H2><PRE>
110        These  functions are described in the XSI Curses standard,
111        Issue 4.  The standard specifies that they return  <STRONG>ERR</STRONG>  on
112        failure, but specifies no error conditions.
113
114        Some  historic  curses  implementations had, as an undocu-
115        mented feature,  the  ability  to  do  the  equivalent  of
116        <STRONG>clearok(...,</STRONG>  <STRONG>1)</STRONG>  by saying <STRONG>touchwin(stdscr)</STRONG> or <STRONG>clear(std-</STRONG>
117        <STRONG>scr)</STRONG>.  This will not work under ncurses.
118
119        This implementation, and others such as Solaris, sets  the
120        current  position  to  0,0  after erasing via <STRONG>werase()</STRONG> and
121        <STRONG>wclear()</STRONG>.  That fact is not documented in other  implemen-
122        tations, and may not be true of implementations which were
123        not derived from SVr4 source.
124
125        Not obvious from  the  description,  most  implementations
126        clear  the screen after <STRONG>wclear</STRONG> even for a subwindow or de-
127        rived window.  If you do not want to clear the screen dur-
128        ing the next <STRONG>wrefresh</STRONG>, use <STRONG>werase</STRONG> instead.
129
130
131 </PRE>
132 <H2>SEE ALSO</H2><PRE>
133        <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>
134
135
136
137                                                          <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>
138 </PRE>
139 <HR>
140 <ADDRESS>
141 Man(1) output converted with
142 <a href="http://www.oac.uci.edu/indiv/ehood/man2html.html">man2html</a>
143 </ADDRESS>
144 </BODY>
145 </HTML>