MirBSD manpage: clear(3), clrtobot(3), clrtoeol(3), curs_clear(3), erase(3), wclear(3), wclrtobot(3), wclrtoeol(3), werase(3)

curs_clear(3)       UNIX Programmer's Manual        curs_clear(3)


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


     # 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);


     The erase and werase routines copy blanks to every  position
     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 com-
     pletely 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 rendi-
     tion (as set by wbkgdset) merged into them.


     All routines return the integer OK on  success  and  ERR  on
     failure.  The  SVr4.0 manual says "or a non-negative integer
     if immedok is set", but this appears to be an error.

     X/Open defines no error conditions. In this  implementation,
     functions  using  a window pointer parameter return an error
     if it is null.


     Note  that  erase,  werase,  clear,  wclear,  clrtobot,  and
     clrtoeol may be macros.


     These functions are described in the  XSI  Curses  standard,

MirBSD #10-current     Printed 2022-12-23                       1

curs_clear(3)       UNIX Programmer's Manual        curs_clear(3)

     Issue  4.   The  standard  specifies that they return ERR on
     failure, but specifies no error conditions.

     Some historic curses implementations had, as an undocumented
     feature, the ability to do the equivalent of clearok(..., 1)
     by saying touchwin(stdscr) or clear(stdscr).  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  implementa-
     tions, and may not be true of implementations which were not
     derived from SVr4 source.


     curses(3), curs_outopts(3), curs_refresh(3)

MirBSD #10-current     Printed 2022-12-23                       2

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