# curs_terminfo 3x 2025-04-05 ncurses 6.5 Library calls

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

## NAME

           del_curterm,  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 tigetflag(const char * cap-code);
           int tigetnum(const char * cap-code);
           char * tigetstr(const char * cap-code);

           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);

           /* deprecated */
           int setterm(const char * term);

## DESCRIPTION

           These  lower-level  functions  of the curses standard must be called by
           programs that deal  directly  with  the  terminfo  database  to  handle
           certain  terminal capabilities, such as programming function keys.  For
           all other functionality, curses functions 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 and codes use the POSIX portable character set.

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

### Initialization

           Call  setupterm  from  your  application  to  have  terminfo manage the
           terminal  device;  this  action  initializes   the   terminal-dependent
           variables  listed in term_variables(3x).  (A curses application calling
           initscr(3x) or newterm(3x) achieves the same result.)  Applications can
           use  the  terminal  capabilities either directly, by object definitions
           corresponding to capability names and codes (see term_variables(3x)) or
           by  calling  the  functions documented here.  setupterm initializes the
           terminfo variables lines and columns as described in use_env(3x).

           Pass  parameterized  string  capability   values   through   tparm   to
           instantiate them.  All terminfo strings (including the output of tparm)
           should be sent to  the  terminal  device  with  tputs  or  putp.   Call
           reset_shell_mode(3x)  to restore the terminal modes before exiting.  (A
           curses application calling endwin(3x) achieves the same result.)

           Programs that use cursor addressing should emit certain capabilities at
           specific times.  Specifically, output

           o   enter_ca_mode upon startup, and

           o   exit_ca_mode before exiting.

           Programs that execute shell subprocesses should

           o   call  reset_shell_mode(3x) and output exit_ca_mode before the shell
               is called, and

           o   output enter_ca_mode and call reset_prog_mode(3x)  after  returning
               from the shell.

           setupterm  reads  in  the  terminfo database, initializing the terminfo
           structures, but does not set up the  output  virtualization  structures
           used by curses.  Its parameters follow.

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

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

                   Higher-level  applications  use  newterm(3x)  to initialize 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  a  hard-copy  type  (lacks
                        destructive backspace), and  cannot  be  used  for  curses
                        applications.    The   library  determines  this  fact  by
                        checking the terminal type's hardcopy (hc) 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 generic_type (gn) capability.

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

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

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

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

### The Terminal State

           setupterm 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  unavailable to
           applications.

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

           set_curterm sets cur_term to nterm, making all of the terminfo Boolean,
           numeric, and string capabilities use the values from nterm.  It returns
           the old value of cur_term.

           del_curterm  releases  the memory pointed to by oterm.  If oterm is the
           same as cur_term, references to any of the terminfo  Boolean,  numeric,
           and   string  capabilities  thereafter  may  refer  to  invalid  memory
           locations until setupterm is called again.

           restartterm is similar to setupterm, but  is  intended  for  use  after
           restoring  program  memory  to  a  previous  state  (for  example, when
           reloading an application that has  been  suspended  from  one  terminal
           session and restored in another).  restartterm assumes that the display
           dimensions and the input and output options are the same as when memory
           was   saved,   but  the  terminal  type  and  line  speed  may  differ.
           Accordingly,  restartterm  saves   relevant   terminal   state,   calls
           setupterm, then restores that state.

### Formatting Output

           tparm  instantiates  the  string  str with parameters pi.  It returns a
           pointer to a character string  representing  str  with  the  parameters
           applied  to "%" expressions within.  Application developers should keep
           in mind some 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 that uses stdarg.h rather than a fixed-
           length  parameter  list.   Its  numeric parameters are ints rather than
           longs.

           tparm  and  tiparm  assume  that  the  application  passes   parameters
           consistent   with  the  terminal  description.   ncurses  provides  two
           extensions as alternatives to deal with untrusted data.

           o   The tiparm_s extension 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) passed as char pointers 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

           String  capabilities  can  contain padding, a time delay (accommodating
           performance limitations of hardware terminals) expressed as $<n>, where
           n is a nonnegative integral count of milliseconds.  If n exceeds 30,000
           (thirty seconds), ncurses caps it at that value.

           tputs interprets time delays in the string str and acts upon them.

           o   The str parameter must be  a  terminfo  string  capability  or  the
               return value of tparm or tiparm.

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

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

           tputs processes each time delay  with  the  delay_output(3x)  function,
           routing any resulting padding characters through this function.

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

           vidputs 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 function putc.

           vidattr is like vidputs, except that it outputs through putchar(3).

           vid_attr and vid_puts correspond to vidattr and vidputs,  respectively.
           They  use multiple parameters to represent the character attributes and
           color; namely,

           o   attrs, of type attr_t, for the attributes and

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

           Use the attribute constants  prefixed  with  "WA_"  with  vid_attr  and
           vid_puts.

           X/Open  Curses  reserves  the opts argument for future use, saying that
           applications must provide a null pointer for  that  argument;  but  see
           section "EXTENSIONS" below.

           While  putp  is  a  lower-level function that does not use higher-level
           curses state, ncurses declares it in curses.h because System V  did  so
           (see section "HISTORY" below).

### Terminal Capability Functions

           tigetflag,  tigetnum,  and  tigetstr return the value of the capability
           corresponding to the terminfo cap-code, such as xenl, passed  to  them.
           The  cap-code  for each capability is given in the table column of that
           name in the "Predefined Capabilities" section of terminfo(5).

           These functions return special values to denote errors.

           tigetflag returns

           -1     if cap-code is not a Boolean capability, or

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

           tigetnum returns

           -2     if cap-code is not a numeric capability, or

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

           tigetstr returns

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

           NULL   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 as follows.

           o   They  add  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).

           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

           Functions  that  return  integers  return  ERR upon failure and OK upon
           success.

           In ncurses,

           del_curtem
                fails if its terminal parameter is null.

           putp calls tputs, returning the same error codes.

           restartterm
                fails if the associated call to setupterm returns ERR.

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

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

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

## NOTES

           The vid_attr function in ncurses is a special case.  It was  originally
           implemented based on a draft of X/Open Curses, as a macro, before other
           parts of the ncurses wide-character API were developed, and unlike  the
           other  wide-character  functions,  is  also  provided  in the non-wide-
           character configuration.

## EXTENSIONS

           The functions marked as extensions originated in ncurses, and  are  not
           found  in  SVr4  curses,  4.4BSD  curses,  or any other previous curses
           implementation.

           ncurses allows opts to be a pointer to int, which  overrides  the  pair
           (short) argument.

## PORTABILITY

           Except  for  setterm,  X/Open Curses Issue 4 describes these functions.
           It specifies no error conditions for them.

           SVr4 describes a successful return value except where "otherwise noted"
           as "an integer value other than ERR".

### Header Files

           On  legacy curses systems, include curses.h and term.h in that order to
           make  visible  the  definitions  of  the  string  arrays  storing   the
           capability names and codes.

### Compatibility Macros

           ncurses implements a few macros for early System V curses compatibility
           (see section "HISTORY" below).  They include crmode, fixterm, gettmode,
           nocrmode, resetterm, saveterm, and setterm.

           In  SVr4,  these  are  found  in  curses.h, but except for setterm, are
           likewise macros.  The one function, setterm, is mentioned in the manual
           page.  It further notes that setterm was replaced by setupterm, stating
           that the call
                  setupterm(term, 1, (int *)0)
           provides the same functionality as
                  setterm(term)
           and discouraging the latter for new programs.

### Legacy Data

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

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

           Extended  terminal  capability  names,  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 used buffered I/O, and wrote to the
           corresponding stdio 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 clean up on receiving SIGTSTP.

           ncurses  6.x  uses  output  buffers  managed  directly by ncurses.  The
           lower-level functions described here that write to the terminal  device
           do  so  via  the standard output stream; they thus are not signal-safe.
           The higher-level functions in  ncurses  employ  alternate  versions  of
           these functions using a 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, sometimes applying it needlessly to function parameters that
               are  passed  by  value  (and  therefore  copied), and in most cases
               overlooking parameters that  normally  would  benefit  from  const.
               Passing const-qualified parameters to functions that do not declare
               them const may prevent the program from compiling.   On  the  other
               hand, "writable strings" are an obsolescent C language feature.

               As  an  extension, ncurses 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.

               ncurses uses a variable argument list, but can be configured to use
               the  fixed-parameter  list.   Portable  applications should provide
               nine 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
               available only  as  a  build-time  configuration  option.   If  not
               specially configured, tparm is the same as tiparm.

           Both forms of tparm have drawbacks.

           o   Most  calls  to  tparm require 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 memory as a pointer.
               That approach dates to the mid-1980s, before  C  was  standardized.
               Since  ANSI C (1989), C language standards do not require a pointer
               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  (for  instance, the ones used for programmable function
               keys).

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

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

       Special TERM treatment
           If ncurses is configured to use a terminal driver that does not  employ
           the POSIX termios API, as with the MinGW port,

           o   setupterm  interprets  a  missing  or  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
               generic_type  (gn)  terminfo capability, while the latter does not.
               A generic terminal is unsuitable for full-screen applications.

           o   setupterm allows explicit use  of  the  Microsoft  Windows  console
               driver  by  checking  whether the TERM environment variable has the
               value "#win32con" or an abbreviation of that string.

### Other Portability Issues

           In SVr4, set_curterm returns an int, OK or  ERR.   We  have  chosen  to
           implement the X/Open Curses semantics.

           In SVr4, the third argument of tputs has the type "int (*)(char)".

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

## HISTORY

           SVr2  (1984)  introduced  the terminfo feature.  Its programming manual
           mentioned the following low-level functions.

           Function    Description
           ------------------------------------------------------------------------
           fixterm     restore terminal to "in curses" state
           gettmode    establish current terminal modes
           mvcur       low level cursor motion
           putp        use tputs to send characters via putchar
           resetterm   set terminal modes to "out of curses" state
           resetty     reset terminal flags to stored value
           saveterm    save current modes as "in curses" state
           savetty     store current terminal flags
           setterm     establish terminal with given type
           setupterm   establish terminal with given type
           tparm       interpolate parameters into string capability
           tputs       apply padding information to a string
           vidattr     like vidputs, but output through putchar
           vidputs     write string to terminal, applying specified attributes

           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      write characters via a function parameter, applying padding

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

           SVr3  (1987)  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 that  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  to
           handle  capabilities  accessed by functions such as vidattr (which used
           more than the two parameters supported by tgoto).

           SVr3  introduced  the  functions   for   switching   between   terminal
           descriptions;   for   example,  set_curterm.   Some  changes  reflected
           incremental improvements to the SVr2 library.

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

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

           SVr4 (1989) added the vid_attr and vid_puts functions.

           Other  low-level  functions  are declared in the curses header files of
           Unix systems, but none are documented.  Those noted  as  "obsolete"  by
           SVr3 remained in use by System V's vi(1) editor.

## SEE ALSO

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

    ncurses 6.5                       2025-04-05                 curs_terminfo(3x)