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curs_clear 3x



curs_clear(3x)                                           curs_clear(3x)




NAME

       erase, werase, clear, wclear, clrtobot, wclrtobot,
       clrtoeol, wclrtoeol - clear all or part of a curses window


SYNOPSIS

       # include <curses.h>

       int erase(void);
       int werase(WINDOW *win);
       int clear(void);
       int wclear(WINDOW *win);
       int clrtobot(void);
       int wclrtobot(WINDOW *win);
       int clrtoeol(void);
       int wclrtoeol(WINDOW *win);


DESCRIPTION

       The erase and werase routines copy blanks to  every  posi-
       tion in the window, clearing the screen.

       The  clear  and wclear routines are like erase and werase,
       but they also call clearok, so that the screen is  cleared
       completely  on  the  next call to wrefresh for that window
       and repainted from scratch.

       The clrtobot and wclrtobot 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 clrtoeol and wclrtoeol 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 wbkgdset) merged into them.


RETURN VALUE

       All routines return the integer OK on success and  ERR  on
       failure.   The SVr4.0 manual says "or a non-negative inte-
       ger if immedok 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.


NOTES

       Note that erase, werase, clear, wclear, clrtobot, and clr-
       toeol may be macros.


PORTABILITY

       These  functions are described in the XSI Curses standard,
       Issue 4.  The standard specifies that they return  ERR  on
       failure, but specifies no error conditions.

       Some  historic  curses  implementations had, as an undocu-
       mented feature,  the  ability  to  do  the  equivalent  of
       clearok(...,  1)  by saying touchwin(stdscr) or clear(std-
       scr).  This will not work under ncurses.

       This implementation, and others such as Solaris, sets  the
       current  position  to  0,0  after erasing via werase() and
       wclear().  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 wclear even for a subwindow or de-
       rived window.  If you do not want to clear the screen dur-
       ing the next wrefresh, use werase instead.


SEE ALSO

       curses(3x), curs_outopts(3x), curs_refresh(3x), curs_vari-
       ables(3x)



                                                         curs_clear(3x)

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