NAME

       dft_fgbg:  use_default_colors, assume_default_colors - use
       terminal's default colors

SYNOPSIS

       #include <curses.h>

       int use_default_colors(void);
       int assume_default_colors(int fg, int bg);

DESCRIPTION

       The use_default_colors() and assume_default_colors() func-
       tions are extensions to the curses library.  They are used
       with terminals that support ISO 6429 color, or equivalent.
       These terminals allow the application to reset color to an
       unspecified default value (e.g., with SGR 39 or SGR 49).

       Applications that paint  a  colored  background  over  the
       whole  screen  do not take advantage of SGR 39 and SGR 49.
       Some applications are designed to work  with  the  default
       background,  using  colors  only  for  text.  For example,
       there are several implementations of the ls program  which
       use  colors to denote different file types or permissions.
       These "color ls" programs do not  necessarily  modify  the
       background  color, typically using only the setaf terminfo
       capability  to  set  the  foreground  color.   Full-screen
       applications  that  use default colors can achieve similar
       visual effects.

       The first function, use_default_colors() tells the  curses
       library  to  assign terminal default foreground/background
       colors to color number  -1.  So  init_pair(x,COLOR_RED,-1)
       will  initialize  pair  x as red on default background and
       init_pair(x,-1,COLOR_BLUE)  will  initialize  pair  x   as
       default foreground on blue.

       The  other,  assume_default_colors() is a refinement which
       tells which colors to paint for color pair 0.  This  func-
       tion  recognizes  a special color number -1, which denotes
       the default terminal color.

       The following are equivalent:
              use_default_colors();
              assume_default_colors(-1,-1);

       These are ncurses extensions.  For other curses  implemen-
       tations,  color  number -1 does not mean anything, just as
       for ncurses before a successful call  of  use_default_col-
       ors() or assume_default_colors().

       Other  curses  implementations do not allow an application
       to modify color pair 0.  They assume that  the  background
       is COLOR_BLACK, but do not ensure that the color pair 0 is
       painted to match the assumption.  If your application does
       not use either use_default_colors() or assume_default_col-
       ors() ncurses will paint a white  foreground  (text)  with
       black background for color pair 0.

RETURN VALUE

       These functions return the integer ERR upon failure and OK
       on success.  They will fail if either  the  terminal  does
       not  support  the orig_pair or orig_colors capability.  If
       the initialize_pair capability is found,  this  causes  an
       error as well.

NOTES

       Associated with this extension, the init_pair(3x) function
       accepts negative arguments to specify  default  foreground
       or background colors.

PORTABILITY

       These  routines  are  specific  to ncurses.  They were not
       supported on Version 7, BSD or System  V  implementations.
       It  is recommended that any code depending on them be con-
       ditioned using NCURSES_VERSION.

SEE ALSO

       curs_color(3x), ded(1).

AUTHOR

       Thomas Dickey (from an analysis of  the  requirements  for
       color xterm for XFree86 3.1.2C, February 1996).