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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>, <STRONG>clrtoeol</STRONG>, <STRONG>wclrtoeol</STRONG>
  50        - 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 position in the win-
  68        dow, clearing the screen.
  69
  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.
  73
  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
  77        erased.
  78
  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.
  81
  82        Blanks created by erasure have the current background rendition (as set
  83        by <STRONG>wbkgdset</STRONG>) merged into them.
  84
  85
  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.
  90
  91        X/Open defines no error conditions.  In this implementation,  functions
  92        using a window pointer parameter return an error if it is null.
  93
  94
  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
  97        macros.
  98
  99
 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
 103        error conditions.
 104
 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.
 108
 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.
 113
 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.
 117
 118
 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>
 121
 122
 123
 124                                                                 <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>
 125 </PRE>
 126 <div class="nav">
 127 <ul>
 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>
 135 </ul>
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