# curs_terminfo 3x

    curs_terminfo(3x)                                            curs_terminfo(3x)

## NAME

           del_curterm, mvcur, putp, restartterm, set_curterm, setupterm,
           tigetflag, tigetnum, tigetstr, tiparm, 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, ...);
           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, ...);

## DESCRIPTION

           These  low-level  routines must be called by programs that have to deal
           directly with the terminfo database to handle certain terminal capabil-
           ities, 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 curs-
           es.h and term.h should be included (in this order) to get  the  defini-
           tions 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 all output.

              errret
                   points to an optional location where an error status can be re-
                   turned  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 sta-
                   tus 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) capability.

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

                   If errret is null, setupterm prints an error message upon find-
                   ing 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 termi-
           nal's capabilities in memory.  If it is called for  different  terminal
           types,  setupterm  allocates new storage for each set of terminal capa-
           bilities.

           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, refer-
           ences to any of the terminfo boolean,  numeric,  and  string  variables
           thereafter  may  refer  to  invalid  memory locations until another se-
           tupterm 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 exam-
           ple, 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  inter-
           face:

           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 capa-
               bilities 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.

### Output Functions

           The  tputs  routine  applies padding information (i.e., by interpreting
           marker embedded in the terminfo capability such as  "$<5>"  as  5  mil-
           liseconds) 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 inter-
               face.

           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 al-
           ways 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  ex-
           tension,  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).

           While putp and mvcur are low-level functions which do not use the high-
           level curses state, they are declared in <curses.h> because SystemV 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 memo-
           ry.  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  com-
           pletion, 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 con-
                   ditions are documented above.

              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  sys-
           tems  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 recommend-
           ed for new programs.  This implementation provides each of  those  sym-
           bols as macros for BSD compatibility,

## HISTORY

           SVr2 introduced the terminfo feature.  Its programming manual mentioned
           these 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  char-
                       acters 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 val-
           ues (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  han-
           dling  functions  such as vidattr (which used more than the two parame-
           ters supported by tgoto).

           SVr3 introduced the functions for switching between  terminal  descrip-
           tions, 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 "obso-
           lete" remained in use by the Unix vi(1) editor.

## PORTABILITY

### 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 ter-
           minal 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-lev-
           el 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 decla-
           rations,  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  con-
               figured  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.

### 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".

           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 re-
           fresh the window before resuming normal curses calls.  Both ncurses and
           System V Release 4 curses implement mvcur using the SCREEN  data  allo-
           cated  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 im-
           plementation 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), ter-
           minfo(5)

                                                                 curs_terminfo(3x)