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  37 <TITLE>curs_clear 3x 2024-05-25 ncurses 6.5 Library calls</TITLE>
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  42 <H1 class="no-header">curs_clear 3x 2024-05-25 ncurses 6.5 Library calls</H1>
  43 <PRE>
  44 <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>                   Library calls                  <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>
  45
  46
  47
  48
  49 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
  50        <STRONG>erase</STRONG>,  <STRONG>werase</STRONG>, <STRONG>clear</STRONG>, <STRONG>wclear</STRONG>, <STRONG>clrtobot</STRONG>, <STRONG>wclrtobot</STRONG>, <STRONG>clrtoeol</STRONG>, <STRONG>wclrtoeol</STRONG>
  51        - clear all or part of a <EM>curses</EM> window
  52
  53
  54 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
  55        <STRONG>#include</STRONG> <STRONG>&lt;curses.h&gt;</STRONG>
  56
  57        <STRONG>int</STRONG> <STRONG>erase(void);</STRONG>
  58        <STRONG>int</STRONG> <STRONG>werase(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG>
  59
  60        <STRONG>int</STRONG> <STRONG>clear(void);</STRONG>
  61        <STRONG>int</STRONG> <STRONG>wclear(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG>
  62
  63        <STRONG>int</STRONG> <STRONG>clrtobot(void);</STRONG>
  64        <STRONG>int</STRONG> <STRONG>wclrtobot(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG>
  65
  66        <STRONG>int</STRONG> <STRONG>clrtoeol(void);</STRONG>
  67        <STRONG>int</STRONG> <STRONG>wclrtoeol(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG>
  68
  69
  70 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
  71
  72 </PRE><H3><a name="h3-erase_werase">erase, werase</a></H3><PRE>
  73        The <STRONG>erase</STRONG> and <STRONG>werase</STRONG> routines copy blanks  to  every  position  in  the
  74        window, clearing the screen.
  75
  76        Blanks created by erasure have the current background rendition (as set
  77        by <STRONG><A HREF="curs_bkgd.3x.html">wbkgdset(3x)</A></STRONG>) merged into them.
  78
  79
  80 </PRE><H3><a name="h3-clear_wclear">clear, wclear</a></H3><PRE>
  81        The <STRONG>clear</STRONG> and <STRONG>wclear</STRONG> routines are like <STRONG>erase</STRONG> and <STRONG>werase</STRONG>, but they  also
  82        call  <STRONG><A HREF="curs_outopts.3x.html">clearok(3x)</A></STRONG>, so that the screen is cleared completely on the next
  83        call to <STRONG>wrefresh</STRONG> for that window and repainted from scratch.
  84
  85
  86 </PRE><H3><a name="h3-clrtobot_wclrtobot">clrtobot, wclrtobot</a></H3><PRE>
  87        The <STRONG>clrtobot</STRONG> and <STRONG>wclrtobot</STRONG> routines erase from the cursor to the end of
  88        screen.   That is, they erase all lines below the cursor in the window.
  89        Also, the current line to  the  right  of  the  cursor,  inclusive,  is
  90        erased.
  91
  92
  93 </PRE><H3><a name="h3-clrtoeol_wclrtoeol">clrtoeol, wclrtoeol</a></H3><PRE>
  94        The <STRONG>clrtoeol</STRONG> and <STRONG>wclrtoeol</STRONG> routines erase the current line to the right
  95        of the cursor, inclusive, to the end of the current line.
  96
  97
  98 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
  99        All routines return the integer <STRONG>OK</STRONG> on success and <STRONG>ERR</STRONG> on failure.
 100
 101        X/Open defines no error conditions.  In this implementation,
 102
 103        <STRONG>o</STRONG>   functions using a window pointer parameter return <STRONG>ERR</STRONG> if it is null
 104
 105        <STRONG>o</STRONG>   <STRONG>wclrtoeol</STRONG> returns an error if the cursor position is about to wrap.
 106
 107
 108 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
 109        Note that <STRONG>erase</STRONG>, <STRONG>werase</STRONG>, <STRONG>clear</STRONG>, <STRONG>wclear</STRONG>, <STRONG>clrtobot</STRONG>, and <STRONG>clrtoeol</STRONG>  may  be
 110        macros.
 111
 112
 113 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
 114        These functions are described in X/Open Curses, Issue 4.
 115
 116        The  SVr4.0  manual  says  that these functions could return "or a non-
 117        negative integer if <STRONG>immedok</STRONG> is set", referring to the  return-value  of
 118        <STRONG>wrefresh</STRONG>.  In that implementation, <STRONG>wrefresh</STRONG> would return a count of the
 119        number of characters written to the terminal.
 120
 121        Some historic curses implementations had, as an  undocumented  feature,
 122        the  ability  to  do  the  equivalent  of  <STRONG>clearok(...,</STRONG>  <STRONG>1)</STRONG>  by  saying
 123        <STRONG>touchwin(stdscr)</STRONG> or <STRONG>clear(stdscr)</STRONG>.  This will not work under <EM>ncurses</EM>.
 124
 125        This implementation, and others  such  as  Solaris,  sets  the  current
 126        position  to 0,0 after erasing via <STRONG>werase</STRONG> and <STRONG>wclear</STRONG>.  That fact is not
 127        documented  in  other  implementations,  and  may  not   be   true   of
 128        implementations which were not derived from SVr4 source.
 129
 130        Not obvious from the description, most implementations clear the screen
 131        after <STRONG>wclear</STRONG> even for a subwindow or derived window.   If  you  do  not
 132        want to clear the screen during the next <STRONG>wrefresh</STRONG>, use <STRONG>werase</STRONG> instead.
 133
 134
 135 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
 136        <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>
 137
 138
 139
 140 ncurses 6.5                       2024-05-25                    <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>
 141 </PRE>
 142 <div class="nav">
 143 <ul>
 144 <li><a href="#h2-NAME">NAME</a></li>
 145 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
 146 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
 147 <ul>
 148 <li><a href="#h3-erase_werase">erase, werase</a></li>
 149 <li><a href="#h3-clear_wclear">clear, wclear</a></li>
 150 <li><a href="#h3-clrtobot_wclrtobot">clrtobot, wclrtobot</a></li>
 151 <li><a href="#h3-clrtoeol_wclrtoeol">clrtoeol, wclrtoeol</a></li>
 152 </ul>
 153 </li>
 154 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
 155 <li><a href="#h2-NOTES">NOTES</a></li>
 156 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
 157 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
 158 </ul>
 159 </div>
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