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  41 <H1 class="no-header">curs_clear 3x</H1>
  42 <PRE>
  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><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>,
  50        <STRONG>clrtoeol</STRONG>, <STRONG>wclrtoeol</STRONG> - clear all or part of a <STRONG>curses</STRONG> window
  51
  52
  53 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
  54        <STRONG>#</STRONG> <STRONG>include</STRONG> <STRONG>&lt;curses.h&gt;</STRONG>
  55
  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>
  64
  65
  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  posi-
  68        tion in the window, clearing the screen.
  69
  70        The  <STRONG>clear</STRONG>  and <STRONG>wclear</STRONG> routines are like <STRONG>erase</STRONG> and <STRONG>werase</STRONG>,
  71        but they also call <STRONG>clearok</STRONG>, so that the screen is  cleared
  72        completely  on  the  next call to <STRONG>wrefresh</STRONG> for that window
  73        and repainted from scratch.
  74
  75        The <STRONG>clrtobot</STRONG> and <STRONG>wclrtobot</STRONG> routines erase from the  cursor
  76        to the end of screen.  That is, they erase all lines below
  77        the cursor in the window.  Also, the current line  to  the
  78        right of the cursor, inclusive, is erased.
  79
  80        The <STRONG>clrtoeol</STRONG> and <STRONG>wclrtoeol</STRONG> routines erase the current line
  81        to the right of the cursor, inclusive, to the end  of  the
  82        current line.
  83
  84        Blanks created by erasure have the current background ren-
  85        dition (as set by <STRONG>wbkgdset</STRONG>) merged into them.
  86
  87
  88 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
  89        All routines return the integer <STRONG>OK</STRONG> on success and  <STRONG>ERR</STRONG>  on
  90        failure.   The SVr4.0 manual says "or a non-negative inte-
  91        ger if <STRONG>immedok</STRONG> is set", but this appears to be an error.
  92
  93        X/Open defines no error conditions.  In  this  implementa-
  94        tion, functions using a window pointer parameter return an
  95        error if it is null.
  96
  97
  98 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
  99        Note that <STRONG>erase</STRONG>, <STRONG>werase</STRONG>, <STRONG>clear</STRONG>, <STRONG>wclear</STRONG>, <STRONG>clrtobot</STRONG>, and <STRONG>clr-</STRONG>
 100        <STRONG>toeol</STRONG> may be macros.
 101
 102
 103 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
 104        These  functions are described in the XSI Curses standard,
 105        Issue 4.  The standard specifies that they return  <STRONG>ERR</STRONG>  on
 106        failure, but specifies no error conditions.
 107
 108        Some  historic  curses  implementations had, as an undocu-
 109        mented feature,  the  ability  to  do  the  equivalent  of
 110        <STRONG>clearok(...,</STRONG>  <STRONG>1)</STRONG>  by saying <STRONG>touchwin(stdscr)</STRONG> or <STRONG>clear(std-</STRONG>
 111        <STRONG>scr)</STRONG>.  This will not work under ncurses.
 112
 113        This implementation, and others such as Solaris, sets  the
 114        current  position  to  0,0  after erasing via <STRONG>werase()</STRONG> and
 115        <STRONG>wclear()</STRONG>.  That fact is not documented in other  implemen-
 116        tations, and may not be true of implementations which were
 117        not derived from SVr4 source.
 118
 119        Not obvious from  the  description,  most  implementations
 120        clear  the screen after <STRONG>wclear</STRONG> even for a subwindow or de-
 121        rived window.  If you do not want to clear the screen dur-
 122        ing the next <STRONG>wrefresh</STRONG>, use <STRONG>werase</STRONG> instead.
 123
 124
 125 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
 126        <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>curs_vari-</STRONG>
 127        <STRONG><A HREF="curs_variables.3x.html">ables(3x)</A></STRONG>
 128
 129
 130
 131                                                          <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>
 132 </PRE>
 133 <div class="nav">
 134 <ul>
 135 <li><a href="#h2-NAME">NAME</a></li>
 136 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
 137 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
 138 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
 139 <li><a href="#h2-NOTES">NOTES</a></li>
 140 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
 141 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
 142 </ul>
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