+ 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 vari-
- ables, or macros (see curs_threads(3x) and
- curs_opaque(3x)) which provide read-only access to curs-
- es's state. In either case, applications should treat
- them as read-only to avoid confusing the library.
+ 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 num-
- ber of color pairs which the terminal can support. Usual-
- ly the number of color pairs will be the product COL-
- ORS*COLORS, however this is not always true:
+
+ 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 a few terminals use HLS colors, which do not follow this rule
- o terminals supporting a large number of colors are lim-
- ited by the number of color pairs that can be repre-
- sented in a signedshort value.
+ o terminals supporting a large number of colors are limited by the
+ number of color pairs that can be represented in a signedshort
+ value.
-
- This variable holds the number of milliseconds to wait af-
- ter 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).
+
+ 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)).
-
- 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).
+
+ 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).
-
+ 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.
-
- Upon initializing curses, a default window called stdscr,
- which is the size of the terminal screen, is created.
- Many curses functions use this window.
+ This is referred to as the "virtual screen" in the curs_kernel(3x),
+ curs_refresh(3x) and curs_outopts(3x) manual pages.
-
+ Upon initializing curses, a default window called stdscr, which is the
+ size of the terminal screen, is created. Many curses functions use
+ this window.
- 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 implementations of curses.
+ If curses is configured to use separate curses/terminfo libraries, most
+ of these variables reside in the curses library.
-
+ 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.
+
+
+