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_clear(3x)

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