focal (3) stdscr.3ncurses.gz

NAME

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

SYNOPSIS

       #include <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  threads(3NCURSES)  and
       opaque(3NCURSES))  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:

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

       •   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
       function-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 window (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 refresh(3NCURSES) and outopts(3NCURSES) manual pages.

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

       This   is   referred   to  as  the  “virtual  screen”  in  the  kernel(3NCURSES),  refresh(3NCURSES)  and
       outopts(3NCURSES) 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.

       •   In SVr4 curses, TABSIZE is initially set from the terminal description'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 position of tabstops for updating both
           the virtual screen with addch(3X) as well as the physical screen with mvcur(3X).

       •   This implementation uses the current value of TABSIZE only for updating 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).

       •   Other implementations differ.  For instance, NetBSD curses  allows  TABSIZE  to  be  set  through  an
           environment variable.  This implementation 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:

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

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

       •   AIX also enforces a limit of 10,000 seconds for ESCDELAY; this implementation 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

       ncurses(3NCURSES), opaque(3NCURSES), terminfo(3NCURSES), threads(3NCURSES), terminfo_variables(3NCURSES),
       terminfo(5).

                                                                                      curses_variables(3NCURSES)