# term_variables 3x 2024-12-28 ncurses 6.5 Library calls

    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 6.5                       2024-12-28                term_variables(3x)