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curs_variables(3X)					    curs_variables(3X)

NAME
       COLORS, COLOR_PAIRS, COLS, ESCDELAY, LINES, TABSIZE, curscr, newscr,
       stdscr -	curses global variables

SYNOPSIS
       #include	<ncurses/curses.h>

       int COLOR_PAIRS;
       int COLORS;
       int COLS;
       int ESCDELAY;
       int LINES;
       int TABSIZE;
       WINDOW *	curscr;
       WINDOW *	newscr;
       WINDOW *	stdscr;

DESCRIPTION
       This page summarizes variables provided by the curses library.  A  more
       complete	description is given in	the curses(3X) manual page.

       Depending  on  the  configuration,  these  may  be actual variables, or
       macros (see curs_threads(3X) and	curs_opaque(3X)) which	provide	 read-
       only  access  to	 curses's  state.  In either case, applications	should
       treat them as read-only to avoid	confusing the library.

   COLOR_PAIRS
       After initializing curses, this variable	contains the number  of	 color
       pairs  which  the  terminal  can	 support.  Usually the number of color
       pairs will be the product COLORS*COLORS,	however	 this  is  not	always
       true:

       o   a few terminals use HLS colors, which do not	follow this rule

       o   terminals  supporting  a  large number of colors are	limited	by the
	   number of color pairs that can be represented  in  a	 signed	 short
	   value.

   COLORS
       After  initializing curses, this	variable contains the number of	colors
       which the terminal can support.

   COLS
       After initializing curses, this variable	 contains  the	width  of  the
       screen, i.e., the number	of columns.

   ESCDELAY
       This variable holds the number of milliseconds to wait after reading an
       escape character, to distinguish	between	an individual escape character
       entered on the keyboard from escape sequences sent by cursor- and func-
       tion-keys (see curses(3X)).

   LINES
       After initializing curses, this variable	contains  the  height  of  the
       screen, i.e., the number	of lines.

   TABSIZE
       This  variable  holds  the number of columns used by the	curses library
       when converting a tab character to spaces as it adds the	tab to a  win-
       dow (see	curs_addch(3X).

   The Current Screen
       This  implementation  of	 curses	uses a special window curscr to	record
       its updates to the terminal screen.

       This is referred	to as the "physical screen"  in	 the  curs_refresh(3X)
       and curs_outopts(3X) manual pages.

   The New Screen
       This  implementation of curses uses a special window newscr to hold up-
       dates to	the terminal screen before applying them to curscr.

       This is referred	to as the "virtual  screen"  in	 the  curs_kernel(3X),
       curs_refresh(3X)	and curs_outopts(3X) manual pages.

   The Standard	Screen
       Upon  initializing curses, a default window called stdscr, which	is the
       size of the terminal screen, is created.	  Many	curses	functions  use
       this window.

NOTES
       The   curses  library  is  initialized  using  either  initscr(3X),  or
       newterm(3X).

       If curses is configured to use separate curses/terminfo libraries, most
       of these	variables reside in the	curses library.

PORTABILITY
       TABSIZE	is  a feature of SVr4 curses which is not documented by	X/Open
       curses.

       o   In SVr4 curses, TABSIZE is initially	set from the terminal descrip-
	   tion's  init_tabs capability.  After	that, it can be	altered	by the
	   applications	using SVr4 curses.

	   SVr4	curses uses the	current	value of TABSIZE to compute the	 posi-
	   tion	 of  tabstops  for  updating both the virtual screen with add-
	   ch(3X) as well as the physical screen with mvcur(3X).

       o   This	implementation uses the	current	value of TABSIZE only for  up-
	   dating  the	virtual	screen.	 It uses the terminal description's it
	   (init_tabs) capability for computing	hardware tabs (i.e., tab stops
	   on the physical screen).

       o   Other  implementations  differ.  For	instance, NetBSD curses	allows
	   TABSIZE to be set through an	environment variable.  This  implemen-
	   tation does not.

	   NetBSD curses does not support hardware tabs; it uses the init_tabs
	   capability and the TABSIZE variable only for	updating  the  virtual
	   screen.

       ESCDELAY	is an extension	in AIX curses:

       o   In AIX, the units for ESCDELAY are fifths of	a millisecond.

       o   The default value for AIX's ESCDELAY	is 0.1 seconds.

       o   AIX	also enforces a	limit of 10,000	seconds	for ESCDELAY; this im-
	   plementation	currently has no upper limit.

       This implementation has long used ESCDELAY with units of	 milliseconds,
       making  it  impossible to be completely compatible with AIX.  Likewise,
       most users have either decided to override the value, or	rely upon  its
       default value.

SEE ALSO
       curses(3X),   curs_opaque(3X),	curs_terminfo(3X),   curs_threads(3X),
       term_variables(3X), terminfo(5).

							    curs_variables(3X)

NAME | SYNOPSIS | DESCRIPTION | NOTES | PORTABILITY | SEE ALSO

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