# curs_terminfo 3x 2023-10-07 ncurses 6.4 Library calls

    curs_terminfo(3x)                Library calls               curs_terminfo(3x)

## NAME

           del_curterm,   mvcur,   putp,   restartterm,   set_curterm,  setupterm,
           tigetflag,  tigetnum,  tigetstr,  tiparm,  tiparm_s,  tiscan_s,  tparm,
           tputs,  vid_attr,  vid_puts,  vidattr,  vidputs  - curses interfaces to
           terminfo database

## SYNOPSIS

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

           TERMINAL *cur_term;

           const char * const boolnames[];
           const char * const boolcodes[];
           const char * const boolfnames[];
           const char * const numnames[];
           const char * const numcodes[];
           const char * const numfnames[];
           const char * const strnames[];
           const char * const strcodes[];
           const char * const strfnames[];

           int setupterm(const char *term, int filedes, int *errret);
           TERMINAL *set_curterm(TERMINAL *nterm);
           int del_curterm(TERMINAL *oterm);
           int restartterm(const char *term, int filedes, int *errret);

           char *tparm(const char *str, ...);
                or
           char *tparm(const char *str, long p1 ... long p9);

           int tputs(const char *str, int affcnt, int (*putc)(int));
           int putp(const char *str);

           int vidputs(chtype attrs, int (*putc)(int));
           int vidattr(chtype attrs);
           int vid_puts(attr_t attrs, short pair, void *opts, int (*putc)(int));
           int vid_attr(attr_t attrs, short pair, void *opts);

           int mvcur(int oldrow, int oldcol, int newrow, int newcol);

           int tigetflag(const char *capname);
           int tigetnum(const char *capname);
           char *tigetstr(const char *capname);

           char *tiparm(const char *str, ...);

           /* extensions */
           char *tiparm_s(int expected, int mask, const char *str, ...);
           int tiscan_s(int *expected, int *mask, const char *str);

## DESCRIPTION

           These low-level routines must be called by programs that have  to  deal
           directly   with  the  terminfo  database  to  handle  certain  terminal
           capabilities,  such  as  programming  function  keys.   For  all  other
           functionality,  curses  routines  are  more  suitable  and their use is
           recommended.

           None of these functions use  (or  are  aware  of)  multibyte  character
           strings such as UTF-8:

           o   capability names use the POSIX portable character set

           o   capability  string  values  have  no  associated encoding; they are
               strings of 8-bit characters.

### Initialization

           Initially, setupterm should be called.  The high-level curses functions
           initscr  and  newterm call setupterm to initialize the low-level set of
           terminal-dependent variables [listed in terminfo(5)].

           Applications can use the terminal  capabilities  either  directly  (via
           header  definitions),  or  by  special  functions.   The  header  files
           curses.h and term.h should be included  (in  this  order)  to  get  the
           definitions for these strings, numbers, and flags.

           The  terminfo  variables lines and columns are initialized by setupterm
           as follows:

           o   If use_env(FALSE) has been called, values  for  lines  and  columns
               specified in terminfo are used.

           o   Otherwise,  if  the  environment variables LINES and COLUMNS exist,
               their values are used.  If these environment variables do not exist
               and  the program is running in a window, the current window size is
               used.  Otherwise, if the environment variables do  not  exist,  the
               values for lines and columns specified in the terminfo database are
               used.

           Parameterized strings should be passed  through  tparm  to  instantiate
           them.   All  terminfo strings (including the output of tparm) should be
           printed with tputs or putp.  Call reset_shell_mode to restore  the  tty
           modes before exiting [see curs_kernel(3x)].

           Programs which use cursor addressing should

           o   output enter_ca_mode upon startup and

           o   output exit_ca_mode before exiting.

           Programs which execute shell subprocesses should

           o   call  reset_shell_mode  and output exit_ca_mode before the shell is
               called and

           o   output enter_ca_mode and call reset_prog_mode after returning  from
               the shell.

           The  setupterm routine reads in the terminfo database, initializing the
           terminfo structures, but does not  set  up  the  output  virtualization
           structures used by curses.  These are its parameters:

              term is the terminal type, a character string.  If term is null, the
                   environment variable TERM is used.

              filedes
                   is the file descriptor used for getting  and  setting  terminal
                   I/O modes.

                   Higher-level  applications use newterm(3x) for initializing the
                   terminal, passing an output stream rather  than  a  descriptor.
                   In   curses,  the  two  are  the  same  because  newterm  calls
                   setupterm, passing the file descriptor derived from its  output
                   stream parameter.

              errret
                   points  to  an  optional  location where an error status can be
                   returned to the caller.  If errret is not null, then  setupterm
                   returns  OK  or  ERR  and  stores a status value in the integer
                   pointed to by errret.  A  return  value  of  OK  combined  with
                   status of 1 in errret is normal.

                   If ERR is returned, examine errret:

                   1    means  that  the  terminal is hardcopy, cannot be used for
                        curses applications.

                        setupterm determines if the entry is a  hardcopy  type  by
                        checking the hc (hardcopy) capability.

                   0    means  that the terminal could not be found, or that it is
                        a generic type, having too little information  for  curses
                        applications to run.

                        setupterm  determines  if  the  entry is a generic type by
                        checking the gn (generic_type) capability.

                   -1   means that the terminfo database could not be found.

                   If errret is null,  setupterm  prints  an  error  message  upon
                   finding an error and exits.  Thus, the simplest call is:

                   setupterm((char *)0, 1, (int *)0);,

              which uses all the defaults and sends the output to stdout.

### The Terminal State

           The  setupterm  routine  stores its information about the terminal in a
           TERMINAL structure pointed to by the global variable cur_term.   If  it
           detects  an error, or decides that the terminal is unsuitable (hardcopy
           or generic), it discards this information, making it not  available  to
           applications.

           If  setupterm  is called repeatedly for the same terminal type, it will
           reuse  the  information.   It  maintains  only  one  copy  of  a  given
           terminal's  capabilities  in  memory.   If  it  is called for different
           terminal types,  setupterm  allocates  new  storage  for  each  set  of
           terminal capabilities.

           The  set_curterm  routine  sets cur_term to nterm, and makes all of the
           terminfo boolean, numeric, and string variables  use  the  values  from
           nterm.  It returns the old value of cur_term.

           The  del_curterm  routine frees the space pointed to by oterm and makes
           it available for further use.   If  oterm  is  the  same  as  cur_term,
           references  to  any  of  the  terminfo  boolean,  numeric,  and  string
           variables thereafter  may  refer  to  invalid  memory  locations  until
           another setupterm has been called.

           The  restartterm  routine  is  similar to setupterm and initscr, except
           that it is called after restoring  memory  to  a  previous  state  (for
           example,   when   reloading  a  game  saved  as  a  core  image  dump).
           restartterm assumes that the windows and the input and  output  options
           are  the  same as when memory was saved, but the terminal type and baud
           rate may be different.   Accordingly,  restartterm  saves  various  tty
           state bits, calls setupterm, and then restores the bits.

### Formatting Output

           The  tparm  routine  instantiates the string str with parameters pi.  A
           pointer is returned to the result of str with the  parameters  applied.
           Application  developers  should  keep  in  mind  these  quirks  of  the
           interface:

           o   Although tparm's actual parameters may be integers or strings,  the
               prototype expects long (integer) values.

           o   Aside  from  the  set_attributes  (sgr)  capability,  most terminal
               capabilities require no more than one or two parameters.

           o   Padding information is ignored  by  tparm;  it  is  interpreted  by
               tputs.

           o   The  capability  string  is  null-terminated.   Use "\200" where an
               ASCII NUL is needed in the output.

           tiparm is a newer form of tparm which uses  <stdarg.h>  rather  than  a
           fixed-parameter list.  Its numeric parameters are integers (int) rather
           than longs.

           Both tparm and tiparm assume that  the  application  passes  parameters
           consistent  with the terminal description.  Two extensions are provided
           as alternatives to deal with untrusted data:

           o   tiparm_s is an extension which is a safer formatting function  than
               tparm or tiparm, because it allows the developer to tell the curses
               library how many parameters to expect in the  parameter  list,  and
               which may be string parameters.

               The  mask  parameter has one bit set for each of the parameters (up
               to 9) which will be passed as char* rather than numbers.

           o   The  extension  tiscan_s  allows  the  application  to  inspect   a
               formatting capability to see what the curses library would assume.

### Output Functions

           The  tputs  routine  applies padding information (i.e., by interpreting
           marker embedded  in  the  terminfo  capability  such  as  "$<5>"  as  5
           milliseconds) to the string str and outputs it:

           o   The  str parameter must be a terminfo string variable or the return
               value from tparm, tiparm, tgetstr, or tgoto.

               The tgetstr and tgoto functions are part of the termcap  interface,
               which  happens  to  share  this  function  name  with  the terminfo
               interface.

           o   affcnt is the number of lines affected, or 1 if not applicable.

           o   putc is a putchar-like routine to which the characters are  passed,
               one at a time.

           The  putp  routine  calls  tputs(str,  1, putchar).  The output of putp
           always goes to stdout, rather than the filedes specified in setupterm.

           The vidputs routine displays the string on the terminal  in  the  video
           attribute mode attrs, which is any combination of the attributes listed
           in curses(3x).  The characters are passed to the  putchar-like  routine
           putc.

           The vidattr routine is like the vidputs routine, except that it outputs
           through putchar.

           The vid_attr and vid_puts routines correspond to vidattr  and  vidputs,
           respectively.   They  use a set of arguments for representing the video
           attributes plus color, i.e.,

           o   attrs of type attr_t for the attributes and

           o   pair of type short for the color-pair number.

           The vid_attr and vid_puts routines are designed to  use  the  attribute
           constants with the WA_ prefix.

           X/Open  Curses  reserves  the opts argument for future use, saying that
           applications must provide a null pointer  for  that  argument.   As  an
           extension,  this  implementation allows opts to be used as a pointer to
           int, which overrides the pair (short) argument.

           The mvcur routine provides low-level cursor motion.   It  takes  effect
           immediately  (rather  than at the next refresh).  Unlike the other low-
           level output functions, which either write to the  standard  output  or
           pass an output function parameter, mvcur uses an output file descriptor
           derived from the output stream parameter of newterm(3x).

           While putp and mvcur are low-level functions which do not use the high-
           level  curses  state,  they are declared in <curses.h> because System V
           did this (see HISTORY).

### Terminal Capability Functions

           The tigetflag, tigetnum and tigetstr routines return the value  of  the
           capability  corresponding  to the terminfo capname passed to them, such
           as xenl.  The capname for each capability is given in the table  column
           entitled capname code in the capabilities section of terminfo(5).

           These routines return special values to denote errors.

           The tigetflag routine returns

           -1     if capname is not a boolean capability, or

           0      if it is canceled or absent from the terminal description.

           The tigetnum routine returns

           -2     if capname is not a numeric capability, or

           -1     if it is canceled or absent from the terminal description.

           The tigetstr routine returns

           (char *)-1
                  if capname is not a string capability, or

           0      if it is canceled or absent from the terminal description.

### Terminal Capability Names

           These null-terminated arrays contain

           o   the short terminfo names ("codes"),

           o   the termcap names ("names"), and

           o   the long terminfo names ("fnames")

           for each of the predefined terminfo variables:

                  const char *boolnames[], *boolcodes[], *boolfnames[]
                  const char *numnames[], *numcodes[], *numfnames[]
                  const char *strnames[], *strcodes[], *strfnames[]

### Releasing Memory

           Each successful call to setupterm allocates memory to hold the terminal
           description.  As a side-effect, it  sets  cur_term  to  point  to  this
           memory.  If an application calls

                  del_curterm(cur_term);

           the memory will be freed.

           The  formatting functions tparm and tiparm extend the storage allocated
           by setupterm:

           o   the "static" terminfo variables [a-z].  Before ncurses  6.3,  those
               were  shared by all screens.  With ncurses 6.3, those are allocated
               per screen.  See terminfo(5) for details.

           o   to improve performance, ncurses 6.3 caches the result of  analyzing
               terminfo  strings  for  their parameter types.  That is stored as a
               binary tree referenced from the TERMINAL structure.

           The higher-level initscr and newterm functions use setupterm.  Normally
           they  do  not free this memory, but it is possible to do that using the
           delscreen(3x) function.

## RETURN VALUE

           Routines that return an integer return ERR upon failure  and  OK  (SVr4
           only  specifies  "an  integer  value  other  than ERR") upon successful
           completion,  unless  otherwise   noted   in   the   preceding   routine
           descriptions.

           Routines that return pointers always return NULL on error.

           X/Open defines no error conditions.  In this implementation

              del_curterm
                   returns an error if its terminal parameter is null.

              putp calls tputs, returning the same error-codes.

              restartterm
                   returns an error if the associated call to setupterm returns an
                   error.

              setupterm
                   returns an error if it cannot allocate enough memory, or create
                   the  initial  windows  (stdscr,  curscr,  newscr).  Other error
                   conditions are documented above.

              tparm
                   returns a null  if  the  capability  would  require  unexpected
                   parameters,  e.g.,  too  many,  too  few,  or  incorrect  types
                   (strings where integers are expected, or vice versa).

              tputs
                   returns an error if the string parameter is null.  It does  not
                   detect  I/O errors: X/Open states that tputs ignores the return
                   value of the output function putc.

### Compatibility macros

           This implementation  provides  a  few  macros  for  compatibility  with
           systems  before  SVr4  (see  HISTORY).   Those include crmode, fixterm,
           gettmode, nocrmode, resetterm, saveterm, and setterm.

           In SVr4, those are found in <curses.h>, but  except  for  setterm,  are
           likewise macros.  The one function, setterm, is mentioned in the manual
           page.  The manual page notes that the setterm routine was  replaced  by
           setupterm, stating that the call

                  setupterm(term, 1, (int *)0)

           provides   the   same   functionality  as  setterm(term),  and  is  not
           recommended for new programs.  This  implementation  provides  each  of
           those symbols as macros for BSD compatibility,

## HISTORY

           SVr2 introduced the terminfo feature.  Its programming manual mentioned
           the following low-level functions.

           Function    Description
           ------------------------------------------------------------------------
           fixterm     restore tty to "in curses" state

           gettmode    establish current tty modes
           mvcur       low level cursor motion
           putp        utility function that uses tputs  to  send  characters  via
                       putchar.
           resetterm   set tty modes to "out of curses" state
           resetty     reset tty flags to stored value
           saveterm    save current modes as "in curses" state
           savetty     store current tty flags
           setterm     establish terminal with given type
           setupterm   establish terminal with given type
           tparm       instantiate a string expression with parameters
           tputs       apply padding information to a string
           vidattr     like vidputs, but outputs through putchar
           vidputs     output  a  string  to  put  terminal  in  a specified video
                       attribute mode

           The programming manual also mentioned functions  provided  for  termcap
           compatibility (commenting that they "may go away at a later date").

           Function   Description
           ------------------------------------------------------------------------
           tgetent    look up termcap entry for given name
           tgetflag   get boolean entry for given id
           tgetnum    get numeric entry for given id
           tgetstr    get string entry for given id
           tgoto      apply parameters to given capability
           tputs      apply  padding  to  capability,  calling  a  function to put
                      characters

           Early terminfo programs obtained capability values  from  the  TERMINAL
           structure initialized by setupterm.

           SVr3  extended  terminfo  by  adding  functions  to retrieve capability
           values (like the termcap interface), and reusing tgoto and tputs:

           Function    Description
           ------------------------------------------------------------------------
           tigetflag   get boolean entry for given id
           tigetnum    get numeric entry for given id
           tigetstr    get string entry for given id

           SVr3 also replaced several of the SVr2 terminfo functions which had  no
           counterpart in the termcap interface, documenting them as obsolete.

           Function    Replaced by
           ------------------------------------------------------------------------
           crmode      cbreak
           fixterm     reset_prog_mode
           gettmode    n/a
           nocrmode    nocbreak
           resetterm   reset_shell_mode
           saveterm    def_prog_mode
           setterm     setupterm

           SVr3  kept  the  mvcur, vidattr and vidputs functions, along with putp,
           tparm and tputs.  The  latter  were  needed  to  support  padding,  and
           handling  functions  such  as  vidattr  (which  used  more than the two
           parameters supported by tgoto).

           SVr3  introduced  the  functions   for   switching   between   terminal
           descriptions,   e.g.,   set_curterm.   Some  of  that  was  incremental
           improvements to the SVr2 library:

           o   The TERMINAL type definition was introduced  in  SVr3.01,  for  the
               term structure provided in SVr2.

           o   The  various  global  variables such as boolnames were mentioned in
               the programming manual at this point,  though  the  variables  were
               provided in SVr2.

           SVr4 added the vid_attr and vid_puts functions.

           There are other low-level functions declared in the curses header files
           on Unix systems,  but  none  were  documented.   The  functions  marked
           "obsolete" remained in use by the Unix vi(1) editor.

## PORTABILITY

### Extensions

           The  functions  marked as extensions were designed for ncurses(3x), and
           are not found in SVr4 curses, 4.4BSD  curses,  or  any  other  previous
           version of curses.

### Legacy functions

           X/Open notes that vidattr and vidputs may be macros.

           The  function setterm is not described by X/Open and must be considered
           non-portable.  All other functions are as described by X/Open.

### Legacy data

           setupterm copies the terminal name to the array ttytype.  This  is  not
           part of X/Open Curses, but is assumed by some applications.

           Other  implementions  may not declare the capability name arrays.  Some
           provide them without declaring them.  X/Open does not specify them.

           Extended terminal capability names, e.g., as defined by tic -x, are not
           stored in the arrays described here.

### Output buffering

           Older  versions  of  ncurses assumed that the file descriptor passed to
           setupterm from initscr or newterm uses buffered I/O, and would write to
           the  corresponding  stream.   In  addition  to  the limitation that the
           terminal was left  in  block-buffered  mode  on  exit  (like  System  V
           curses),  it  was  problematic because ncurses did not allow a reliable
           way to cleanup on receiving SIGTSTP.

           The current version (ncurses6) uses output buffers managed directly  by
           ncurses.  Some of the low-level functions described in this manual page
           write to the standard output.  They are  not  signal-safe.   The  high-
           level  functions  in  ncurses use alternate versions of these functions
           using the more reliable buffering scheme.

### Function prototypes

           The X/Open Curses prototypes  are  based  on  the  SVr4  curses  header
           declarations,  which  were  defined at the same time the C language was
           first standardized in the late 1980s.

           o   X/Open Curses uses const  less  effectively  than  a  later  design
               might,  in  some cases applying it needlessly to values are already
               constant, and in most cases overlooking parameters  which  normally
               would  use const.  Using constant parameters for functions which do
               not use const may prevent the program from compiling.  On the other
               hand, writable strings are an obsolescent feature.

               As  an  extension,  this implementation can be configured to change
               the function prototypes to use the const keyword.  The ncurses  ABI
               6 enables this feature by default.

           o   X/Open  Curses  prototypes tparm with a fixed number of parameters,
               rather than a variable argument list.

               This implementation uses a  variable  argument  list,  but  can  be
               configured  to use the fixed-parameter list.  Portable applications
               should provide 9 parameters after the format; zeroes are  fine  for
               this purpose.

               In  response  to review comments by Thomas E. Dickey, X/Open Curses
               Issue 7 proposed the tiparm function in mid-2009.

               While tiparm is always provided in ncurses, the older form is  only
               available  as  a build-time configuration option.  If not specially
               configured, tparm is the same as tiparm.

           Both forms of tparm have drawbacks:

           o   Most of the calls to tparm use only one or two parameters.  Passing
               nine on each call is awkward.

               Using  long  for the numeric parameter type is a workaround to make
               the parameter use the same amount of  stack  as  a  pointer.   That
               approach  dates  back  to the mid-1980s, before C was standardized.
               Since then, there is a standard (and pointers are not  required  to
               fit in a long).

           o   Providing  the  right  number of parameters for a variadic function
               such  as  tiparm  can  be  a  problem,  in  particular  for  string
               parameters.   However,  only a few terminfo capabilities use string
               parameters (e.g., the ones used for programmable function keys).

               The ncurses library checks usage of these capabilities, and returns
               an  error  if  the capability mishandles string parameters.  But it
               cannot check if a calling program provides  strings  in  the  right
               places for the tparm calls.

               The  tput(1)  program  checks  its use of these capabilities with a
               table, so that it calls tparm correctly.

### Special TERM treatment

           If configured to use the terminal-driver, e.g., for the MinGW port,

           o   setupterm interprets a missing/empty TERM variable as  the  special
               value "unknown".

               SVr4 curses uses the special value "dumb".

               The  difference  between  the  two  is  that the former uses the gn
               (generic_type) terminfo capability, while the latter does  not.   A
               generic terminal is unsuitable for full-screen applications.

           o   setupterm  allows explicit use of the the windows console driver by
               checking if $TERM is set to "#win32con" or an abbreviation of  that
               string.

### Other portability issues

           In  System  V Release 4, set_curterm has an int return type and returns
           OK or ERR.  We have chosen to implement the X/Open Curses semantics.

           In System V Release 4, the third argument of tputs  has  the  type  int
           (*putc)(char).

           At  least one implementation of X/Open Curses (Solaris) returns a value
           other than OK/ERR from tputs.  That returns the length of  the  string,
           and does no error-checking.

           X/Open  notes  that after calling mvcur, the curses state may not match
           the actual terminal state, and that an  application  should  touch  and
           refresh  the  window before resuming normal curses calls.  Both ncurses
           and System V Release 4 curses implement mvcur  using  the  SCREEN  data
           allocated  in either initscr or newterm.  So though it is documented as
           a terminfo function, mvcur is really a curses  function  which  is  not
           well specified.

           X/Open  states  that  the  old  location must be given for mvcur.  This
           implementation allows the caller to use -1's for the old ordinates.  In
           that case, the old location is unknown.

## SEE ALSO

           curses(3x),   curs_initscr(3x),   curs_kernel(3x),   curs_memleaks(3x),
           curs_termcap(3x),  curs_variables(3x),   term_variables(3x),   putc(3),
           terminfo(5)

    ncurses 6.4                       2023-10-07                 curs_terminfo(3x)