COLORS, COLOR_PAIRS, COLS, ESCDELAY, LINES, TABSIZE, curscr, newscr,
stdscr - curses global variables
WINDOW * curscr;
WINDOW * newscr;
WINDOW * stdscr;
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.
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
· 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
After initializing curses, this variable contains the number of colors
which the terminal can support.
After initializing curses, this variable contains the width of the
screen, i.e., the number of columns.
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)).
After initializing curses, this variable contains the height of the
screen, i.e., the number of lines.
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
The curses library is initialized using either initscr(3X), or
If curses is configured to use separate curses/terminfo libraries, most
of these variables reside in the curses library.
ESCDELAY and TABSIZE are extensions, not provided in most other imple‐
mentations of curses.
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 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
curses(3X), curs_opaque(3X), curs_terminfo(3X), curs_threads(3X),