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curs_terminfo(3)                                              curs_terminfo(3)




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
       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 all output.

          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) 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.

   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).

       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 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.

          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
       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
                   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

   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.

   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 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)



                                                               curs_terminfo(3)

ncurses 6.4 - Generated Thu Jan 5 09:26:31 CST 2023
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