# default_colors 3x

## NAME

           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).