assume_default_colors

default_colors(3X)					   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()  functions  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 pro-
       gram 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 function 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 implementations, color
       number  -1  does	 not mean anything, just as for ncurses before a suc-
       cessful call of use_default_colors() 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_colors() 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 conditioned 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).



							   default_colors(3X)