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:
• capability names use the POSIX portable character set
• capability string values have no associated encoding; they
are strings of 8-bit characters.
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
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:
• If use_env(FALSE) has been called, values for lines and
columns specified in terminfo are used.
• 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
Programs which use cursor addressing should
• output enter_ca_mode upon startup and
• output exit_ca_mode before exiting.
Programs which execute shell subprocesses should
• call reset_shell_mode and output exit_ca_mode before the
shell is called and
• 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
term is the terminal type, a character string. If term is
null, the environment variable TERM is used.
is the file descriptor used for all output.
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
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.
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:
• Although tparm's actual parameters may be integers or
strings, the prototype expects long (integer) values.
• Aside from the set_attributes (sgr) capability, most terminal
capabilities require no more than one or two parameters.
• Padding information is ignored by tparm; it is interpreted by
• 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.
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:
• 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
• affcnt is the number of lines affected, or 1 if not
• 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
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.,
• attrs of type attr_t for the attributes and
• 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
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
• the short terminfo names (“codes”),
• the termcap names (“names”), and
• the long terminfo names (“fnames”)
for each of the predefined terminfo variables:
const char *boolnames, *boolcodes, *boolfnamesconst char *numnames, *numcodes, *numfnamesconst char *strnames, *strcodes, *strfnamesReleasing 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
the memory will be freed.
The formatting functions tparm and tiparm extend the storage
allocated by setupterm:
• 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.
• 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
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.
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
Routines that return pointers always return NULL on error.
X/Open defines no error conditions. In this implementation
returns an error if its terminal parameter is null.
putp calls tputs, returning the same error-codes.
returns an error if the associated call to setupterm
returns an error.
returns an error if it cannot allocate enough memory, or
create the initial windows (stdscr, curscr, newscr).
Other error conditions are documented above.
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.
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,
SVr2 introduced the terminfo feature. Its programming manual
mentioned these low-level functions:
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
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:
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
Function Replaced by
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:
• The TERMINAL type definition was introduced in SVr3.01, for
the term structure provided in SVr2.
• 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.
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
Legacy datasetupterm 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
Extended terminal capability names, e.g., as defined by @TIC@ -x,
are not stored in the arrays described here.
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
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.
• 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
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.
• 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
• setupterm interprets a missing/empty TERM variable as the
special value “unknown”.
• 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
In System V Release 4, the third argument of tputs has the type
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.
This page is part of the ncurses (new curses) project.
Information about the project can be found at
⟨https://www.gnu.org/software/ncurses/ncurses.html⟩. If you have
a bug report for this manual page, send it to
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