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| * @Id: curs_clear.3x,v 1.11 2007/12/29 15:58:38 tom Exp @ |
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| <TITLE>curs_clear 3x</TITLE> |
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| <H1>curs_clear 3x</H1> |
| <HR> |
| <PRE> |
| <!-- Manpage converted by man2html 3.0.1 --> |
| <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG> <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG> |
| |
| |
| |
| |
| </PRE> |
| <H2>NAME</H2><PRE> |
| <STRONG>erase</STRONG>, <STRONG>werase</STRONG>, <STRONG>clear</STRONG>, <STRONG>wclear</STRONG>, <STRONG>clrtobot</STRONG>, <STRONG>wclrtobot</STRONG>, |
| <STRONG>clrtoeol</STRONG>, <STRONG>wclrtoeol</STRONG> - clear all or part of a <STRONG>curses</STRONG> window |
| |
| |
| </PRE> |
| <H2>SYNOPSIS</H2><PRE> |
| <STRONG>#</STRONG> <STRONG>include</STRONG> <STRONG><curses.h></STRONG> |
| |
| <STRONG>int</STRONG> <STRONG>erase(void);</STRONG> |
| <STRONG>int</STRONG> <STRONG>werase(WINDOW</STRONG> <STRONG>*win);</STRONG> |
| <STRONG>int</STRONG> <STRONG>clear(void);</STRONG> |
| <STRONG>int</STRONG> <STRONG>wclear(WINDOW</STRONG> <STRONG>*win);</STRONG> |
| <STRONG>int</STRONG> <STRONG>clrtobot(void);</STRONG> |
| <STRONG>int</STRONG> <STRONG>wclrtobot(WINDOW</STRONG> <STRONG>*win);</STRONG> |
| <STRONG>int</STRONG> <STRONG>clrtoeol(void);</STRONG> |
| <STRONG>int</STRONG> <STRONG>wclrtoeol(WINDOW</STRONG> <STRONG>*win);</STRONG> |
| |
| |
| </PRE> |
| <H2>DESCRIPTION</H2><PRE> |
| The <STRONG>erase</STRONG> and <STRONG>werase</STRONG> routines copy blanks to every posi- |
| tion in the window, clearing the screen. |
| |
| The <STRONG>clear</STRONG> and <STRONG>wclear</STRONG> routines are like <STRONG>erase</STRONG> and <STRONG>werase</STRONG>, |
| but they also call <STRONG>clearok</STRONG>, so that the screen is cleared |
| completely on the next call to <STRONG>wrefresh</STRONG> for that window |
| and repainted from scratch. |
| |
| The <STRONG>clrtobot</STRONG> and <STRONG>wclrtobot</STRONG> routines erase from the cursor |
| to the end of screen. That is, they erase all lines below |
| the cursor in the window. Also, the current line to the |
| right of the cursor, inclusive, is erased. |
| |
| The <STRONG>clrtoeol</STRONG> and <STRONG>wclrtoeol</STRONG> routines erase the current line |
| to the right of the cursor, inclusive, to the end of the |
| current line. |
| |
| Blanks created by erasure have the current background ren- |
| dition (as set by <STRONG>wbkgdset</STRONG>) merged into them. |
| |
| |
| </PRE> |
| <H2>RETURN VALUE</H2><PRE> |
| All routines return the integer <STRONG>OK</STRONG> on success and <STRONG>ERR</STRONG> on |
| failure. The SVr4.0 manual says "or a non-negative inte- |
| ger if <STRONG>immedok</STRONG> is set", but this appears to be an error. |
| |
| X/Open defines no error conditions. In this implementa- |
| tion, functions using a window pointer parameter return an |
| error if it is null. |
| |
| |
| </PRE> |
| <H2>NOTES</H2><PRE> |
| Note that <STRONG>erase</STRONG>, <STRONG>werase</STRONG>, <STRONG>clear</STRONG>, <STRONG>wclear</STRONG>, <STRONG>clrtobot</STRONG>, and <STRONG>clr-</STRONG> |
| <STRONG>toeol</STRONG> may be macros. |
| |
| |
| </PRE> |
| <H2>PORTABILITY</H2><PRE> |
| These functions are described in the XSI Curses standard, |
| Issue 4. The standard specifies that they return <STRONG>ERR</STRONG> on |
| failure, but specifies no error conditions. |
| |
| Some historic curses implementations had, as an undocu- |
| mented feature, the ability to do the equivalent of |
| <STRONG>clearok(...,</STRONG> <STRONG>1)</STRONG> by saying <STRONG>touchwin(stdscr)</STRONG> or <STRONG>clear(std-</STRONG> |
| <STRONG>scr)</STRONG>. This will not work under ncurses. |
| |
| This implementation, and others such as Solaris, sets the |
| current position to 0,0 after erasing via <STRONG>werase()</STRONG> and |
| <STRONG>wclear()</STRONG>. That fact is not documented in other implemen- |
| tations, and may not be true of implementations which were |
| not derived from SVr4 source. |
| |
| Not obvious from the description, most implementations |
| clear the screen after <STRONG>wclear</STRONG> even for a subwindow or de- |
| rived window. If you do not want to clear the screen dur- |
| ing the next <STRONG>wrefresh</STRONG>, use <STRONG>werase</STRONG> instead. |
| |
| |
| </PRE> |
| <H2>SEE ALSO</H2><PRE> |
| <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_clear.3x.html">curs_clear(3x)</A></STRONG> |
| </PRE> |
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