term_variables(3X)               Library calls              term_variables(3X)

NAME

     SP, acs_map, boolcodes, boolfnames, boolnames, cur_term, numcodes,
     numfnames, numnames, strcodes, strfnames, strnames, ttytype - terminfo
     global variables

SYNOPSIS

     #include <curses.h>
     #include <term.h>

     chtype acs_map[];

     SCREEN * SP;

     TERMINAL * cur_term;

     char ttytype[];

     NCURSES_CONST char * const boolcodes[];
     NCURSES_CONST char * const boolfnames[];
     NCURSES_CONST char * const boolnames[];

     NCURSES_CONST char * const numcodes[];
     NCURSES_CONST char * const numfnames[];
     NCURSES_CONST char * const numnames[];

     NCURSES_CONST char * const strcodes[];
     NCURSES_CONST char * const strfnames[];
     NCURSES_CONST char * const strnames[];

DESCRIPTION

     This page summarizes variables provided by the curses library's lower-
     level terminfo interface.  Locate a more complete description in the
     curs_terminfo(3X) manual page.

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

Alternate Character Set Mapping

     After initializing the curses or terminfo interfaces, the acs_map array
     holds information used to translate cells with the A_ALTCHARSET video
     attribute into line-drawing characters.

     The encoding of the information in this array has changed periodically.
     Application developers need only know that it is used for the "ACS_"
     constants in curses.h.

     The comparable data for the wide-character library are not exposed as
     symbols in the API.

Current Terminal Data

     After initializing the curses or terminfo interfaces, cur_term contains
     data describing the current terminal.  It is also updated as a side
     effect of set_term(3X) and delscreen(3X).

     It is possible to save a value of cur_term for subsequent use as a
     parameter to set_term(3X) for switching between screens.  Alternatively,
     one can save the return value from newterm(3X) or setupterm(3X) to reuse
     in set_term(3X).

terminfo Lookup Tables

     The tic(1) and infocmp(1) programs use lookup tables for the long and
     short names of terminfo capabilities, as well as the corresponding names
     for termcap capabilities.  These are available to other applications,
     though the hash tables used by the terminfo and termcap functions are
     not.

     terminfo stores capability names in arrays with an "f" (eff) in their
     names: boolfnames, numfnames, and strfnames.  It stores the briefer
     capability codes in arrays without the "f": boolnames, numnames, and
     strnames.  The corresponding termcap capability codes are stored in
     boolcodes, numcodes, and strcodes.  terminfo(5) catalogs these.

Terminal Type

     A terminal description begins with one or more terminal names separated
     by "|" (vertical bars).  On initialization of the curses or terminfo
     interfaces, setupterm(3X) copies the terminal name to the array ttytype.

terminfo Names

     In addition to the variables, term.h also defines a symbol for each
     terminfo capability name.  These are in terms of the symbol CUR, which is
     defined

            #define CUR ((TERMTYPE *)(cur_term))->

     These symbols provide a faster method of accessing terminfo capabilities
     than using, for example, tigetstr(3X).

     The definition of CUR is implementation-dependent, but each terminfo
     library defines these names to point into the in-memory description of
     the current terminal.  For example, in ncurses, the expressions
     tigetstr("key_dc") and "CUR Strings[59]" are equivalent.

terminfo and curses

     setupterm(3X) initializes the lower-level terminfo interface.  The
     higher-level curses interface uses the terminfo interface internally; the
     symbol SP bridges the curses SCREEN type with the terminfo TERMINAL type.

PORTABILITY

     X/Open Curses does not describe any of these symbols except for cur_term.
     (The inclusion of cur_term appears to be an oversight, since other
     comparable low-level information is omitted by X/Open.)

     Other implementations may have comparable variables.  Some
     implementations provide the variables in their libraries, but omit them
     from the header files.

     All implementations that provide terminfo interfaces add definitions as
     described in the "terminfo Names" section above.  Most, but not all, base
     the definition upon the cur_term variable.

SEE ALSO

     curses(3X), curs_terminfo(3X), curs_threads(3X), terminfo(5)

ncurses 6.6                       2025-11-11                term_variables(3X)