Announcing ncurses 6.6

Announcing ncurses 6.6
ncurses/
Announcing ncurses 6.6
Overview
The
ncurses
(new curses) library is a free software emulation of curses in System V Release 4.0 (SVr4), and more. It uses terminfo format, supports pads and color and multiple highlights and forms characters and function-key mapping, and has all the other SVr4-curses enhancements over BSD curses. SVr4 curses became the basis of X/Open Curses.
In mid-June 1995, the maintainer of 4.4BSD curses declared that he considered 4.4BSD curses obsolete, and encouraged the keepers of
unix
releases such as BSD/OS, FreeBSD and NetBSD to switch over to
ncurses
Since 1995,
ncurses
has been ported to many systems:
It is used in almost every system based on the Linux kernel (aside from some embedded applications).
It is used as the system curses library on OpenBSD, FreeBSD and MacOS.
It is used in environments such as Cygwin and MinGW. The first of these was EMX on OS/2 Warp.
It is used (though usually not as the
system
curses) on all of the vendor
unix
systems, e.g., AIX, HP-UX, IRIX64, SCO, Solaris, Tru64.
It should work readily on any ANSI/POSIX-conforming
unix
The distribution includes the library and support utilities, including
captoinfo
, a termcap conversion tool
clear
, utility for clearing the screen
infocmp
, the terminfo decompiler
tabs
, set tabs on a terminal
tic
, the terminfo compiler
toe
, list (table of) terminfo entries
tput
, utility for retrieving terminal capabilities in shell scripts
tset
, to initialize the terminal
Full manual pages are provided for the library and tools.
The
ncurses
distribution is available at
ncurses
homepage
or
It is also available at the GNU distribution site
Release Notes
These notes are for
ncurses
6.6, released
December 30, 2025
This release is designed to be source-compatible with
ncurses
5.0 through 6.5; providing extensions to the application binary interface (ABI). Although the source can still be configured to support the
ncurses
5 ABI, the reason for the release is to reflect improvements to the
ncurses
6 ABI and the supporting utility programs.
There are numerous other improvements listed in this announcement.
The most
important bug-fixes/improvements
dealt with robustness issues. The release notes also mention some other bug-fixes, but are focused on new features and improvements to existing features since
ncurses
6.5 release.
Library improvements
Terminal driver improvements
This release focuses on improvements to the MinGW/Windows terminal driver. The terminal driver for MinGW32 was introduced in
2009
. A new version of the terminal driver to support Windows Terminal was begun in
2020
. However, there were some differences:
Both drivers use
Console API
; the later Windows driver also provides for using character escape sequences.
The MinGW32 driver was designed to imitate POSIX terminal I/O data types to simplify integration with the existing sources.
The newer Windows driver did not integrate with the sources in the same way. In particular, the
reset
utility was incomplete.
Windows Terminal support for Console API is incomplete, lacking mouse support. Additionally, its developers took a few years to resolve issues with carriage-return versus line-feed translation.
Reflecting on these problems, both MinGW and Windows drivers are still provided in ncurses through the current release.
The two drivers are similar, but in developing the Windows driver some renaming and refactoring was done. That resulted in duplicate source files. This release eliminates the duplication.
These improvements have been made to the terminal driver:
made
win_driver.c
obsolete in favor of
win32_driver.c
made
win32_curses.h
obsolete in favor of
nc_win32.h
added configure check for Win32 named pipes feature, using that to make
nc_mingw.h
obsolete in favor of
nc_win32.h
separated the
_NC_WINDOWS
platform macro into
_NC_WINDOWS_NATIVE
, for MinGW and other native Win32 support, and
_NC_WINDOWS
, to make some Win32 features available under the Cygwin runtime, in this case the term-driver.
modified MinGW32 configuration to account for its use of Windows-style pathnames in filesystem checks.
changed
MS_TERMINAL
symbol to
DEFAULT_TERM_VAR
updated
ncurses/wcwidth.c
, for MinGW ports, from xterm.
made fixes for reading Unicode characters in MinGW/Windows port
improved Windows driver by restoring the scroll buffer and console mode, e.g., when
reset_prog_mode
or
endwin
is called
simplified include for
wchar.h
in Windows port by removing the platform ifdef's
modified driver for MinGW to handle shift-tab and control-tab as back-tab
made fixes for port using clang-cl or cl MSVC
Other improvements
These are improvements to existing features:
add comments to generated
term.h
to hint the configure options used
change scope of
TTY
GET_TTY
and
SET_TTY
to ncurses-internals
improved mouse driver
modify
handle_wheel
case 2 to ignore the event as in case 1 for mouse version 1, since that corresponds to a button 6 or 7 event which is not supported with ABI 6.
use separate read/write pointers in the mouse event queue to work with too-close events for the click-detection to work reliably, and further improve that in case
mouseinterval(0)
is used to suppress click-detection.
modify treatment of
“n”
parameter for
waddnstr
waddnwstr
, and
wins_nwstr
to return
OK
when
“n”
is zero, for consistency with other implementations
modify
wattron
wattroff
calls in
form/m_post.c
to call
wattr_on
and
wattr_off
to omit cast used in the former for X/Open compatibility
change
winwstr
to a generated function, using the macro definition, moving its handling of negative length parameter into
winnwstr
change
winwstr
to return wide character count instead of
OK
disallow directories and block/character devices in safe-open.
amend
scr_restore
and
scr_init
to remove the target window only after validating the source window which will replace the target
modify
_nc_flush
to also flush
stderr
to help the
flash
capability to work in
bash
trim padding from
sgr
expression used in
trim_sgr0
, to avoid copying the padding into the resulting sgr0
modify
misc/Makefile.in
and
misc/run_tic.in
so that
$DESTDIR
is set and used only in the makefile.
modify
MKfallback.sh
to eliminate
TERMINFO
environment variable.
add
-x
option to
infocmp
in
MKfallback.sh
limit value from
ESCDELAY
environment variable to 30 seconds, like other delay limits.
limit values from
LINES
and
COLUMNS
environment variables to 512
added check in
wresize
for out-of-range dimensions
improved error-handling in c++ binding
improved error-reporting in
write_entry.c
amended limit used in
alloc_pair
, by applying an adjustment for default colors only when the maximum number of color pairs is greater than the maximum number of colors
added limit-checks in
alloc_entry.c
and
alloc_ttype.c
to avoid indexing errors when using
infocmp
to compare all capabilities when processing a malformed terminfo binary which has a valid header
added a null pointer check in mouse-initialization, for the Windows driver
added some null-pointer checks after
malloc
s in test-programs.
These are corrections to existing features:
removed test in
wgetch
which applied
notimeout
to the initial read of a character
added check for special case of
wcrtomb
converting a single byte code to a different single byte code, which glibc does for code 160 in the KOI8-R encoding
corrected
_nc_to_char
for the case when
wctob
is not found by configure script
revised loop in
wins_nwstr
, to ensure that non-spacing characters are combined with the base spacing character
modified checks in
delwin
to avoid checking if the window is a pad until first checking if it is still on the active window-list
Program improvements
Utilities
Several improvements were made to the utility programs.
infocmp
improved
infocmp
-E
-e
fallback feature
prefix names with “
ti_
” if they begin with a digit, e.g., 9term
escape backslashes and double-quotes in description fields
modified
infocmp
-E
-e
fallback feature to reduce stricter compiler warnings for the extended capability data.
modified
infocmp
and
tabs
to use actual name in usage and header.
improved error-message from
infocmp
when a terminal entry cannot be opened
tic
increased limit on use-clauses from 32 to 40, warn but allow entries which exceed the old limit.
added check for infinite loop in
tic
's use-resolution.
added a buffer-limit check in
postprocess_termcap
tput
Warn about capabilities which expect parameters where none are given. Also, repair the feature where multiple capabilities can be handled on a single line.
Examples
Along with the library and utilities, improvements were made to the
ncurses-examples
add help-popup for
test_instr.c
test_inwstr.c
add options to
test/worm.c
for benchmarking.
improve
-t
option of
test/gdc.c
, allowing hours only, or hours and minutes only.
correct dimensions in
test/popup_msg.c
, fixing an overrun.
modify
test/demo_keyok.c
to accept
^Q
for quit, for consistency.
add option “
-c
” to test programs to illustrate a non-blank character in the window background property.
reserve
-c
-l
options in
test/*.c
for command/logging like
vttest
There is one new demo/test program:
ncurses/report_ctype.c
Shows a chart of the first 256 character codes, which are not as consistent across platforms for ctype versus wctype as some suppose.
Terminal database
There are several new terminal descriptions:
ghostty
illumos
sun-16color
sun-256color
, and
sun-direct
ms-terminal-direct
pangoterm
rlogin-color
sclp
vt520-w
and
vt525-w
along with building blocks
linux+lockeys
xterm+r5+lockeys
xterm+r5+fkeys
vt100+pf1-pf4
vt220+ufkeys
vt220+sfkeys
ecma+standout
ecma+underline
wyse+cvis
There are many changes to existing terminal descriptions. Some were updates to several descriptions, using the
infocmp
-u
” option in a script to determine which
building-block
entries could be used to replace multiple capability settings (and trim redundant information).
Other changes include:
use
xterm+keypad
in
pccon+base
use
bracketed+paste
in
nsterm
rlogin-color
screen
terminology
use extended-keys in
djgpp
2.05
update/correct some of the rv/xr strings, checked with
tack
add rv code for
alacritty
add xr code for
putty
add rv/xr codes for
domterm
mintty
mlterm
contour
ghostty
iterm2
kitty
konsole
vscode
vte
wezterm
improve use-clauses:
ansi+cup
ansi+idl1
ansi+rca
ansi+rca2
ansi+sgrso
ansi+sgrul
sclp
add kf1 to kf5
use
ansi+rca
use
vt220+pcedit
vt525
add color
add op
wezterm
use
xterm+alt+title
omit its broken left/right margin feature
update
contour
update
ms-terminal
add XM/xm to ms-terminal, to enable mouse with experimental Windows driver
update
st
to 0.8.5
update
teraterm
to 5.0
update
foot
to 1.18.1
update
iTerm2
to 3.5.0
Documentation
As usual, this release
improves documentation by describing new features,
attempts to improve the description of features which users have found confusing
fills in overlooked descriptions of features which were described in the
NEWS
file but treated sketchily in manual pages.
In addition to providing background information to explain these features and show how they evolved, there are corrections, clarifications, etc.:
Corrections:
corrected note about box() in curs_border.3x
added note on scrolling and lower-right corner to waddch and wadd_wch manual pages.
Other improvements:
This release has many changes to improve the formatting and style of the man pages.
Table layout in the man pages has been revised.
The
ncurses HOWTO
and its sample programs has been updated.
There are no new manual pages (all of the manual page updates are to existing pages).
Interesting bug-fixes
Configuration changes
Major changes
Improvements made to configure checks include
improve configure check for “install”.
add check for build-time utilities, in case cross-compiling is setup with an invalid
$BUILD_CC
add configure check for

, which may be needed for flatpacks
add a consistency-check for termio(s)/tty headers, to help with cross-compiles
modify configure check for
MAKEFLAGS
MFLAGS
to ignore existing value of these environment variables
improve configurability of
alloca
as used in Windows ports.
modify configure script checks for
stdbool.h
to fix build with older gcc version.
add to the possible headers declaring the C++
std::bad_alloc
modify check for
stdbool.h
to be more conservative in case the headers are used with a compiler other than that which was used to configure
remove dependency on
stdbool.h
from configure script check for type of
bool
when C++ binding is omitted.
Configuration options
There are a few new configure options:
--enable-install-prefix
Modify behavior of
$DESTDIR
to merge or replace the value set by
--prefix
--enable-named-pipes
The Windows driver uses named pipes for communicating with a pseudo console, allowing it to use escape sequences rather than Console API. This works well with mintty. On the downside, this feature may not work well with the Windows Terminal due to a longstanding bug in
conhost.exe
#9461
).
These configure options are modified:
--enable-exp-win32
This option is obsolete, replaced by
--enable-named-pipes
--enable-term-driver
This is enabled by default on platforms where the Windows driver can be compiled, e.g., Cygwin, MinGW32 and MSYS2.
Package configuration scripts
The configure script and makefiles optionally generate a script which reports the compiler and linker options needed to build a program with ncurses, as well as a data file which is used via pkg-config for the same purpose. Several improvements were made for these scripts:
improved filtering of
-L
options in
misc/gen-pkgconfig.in
and in
misc/ncurses-config.in
modified
ncurses*-config
to add
-I
option in
--cflag
where needed for
--disable-overwrite
to match ".pc" files.
suppressed
-g
and
-fXXX
flags from
CFLAGS
in
misc/ncurses-config.in
modified configure script to allow for
pkg-config
using DOS/Windows pathname syntax
modified
misc/ncurses-config.in
, improved match with
pkg-config output
adjusted naming of test packages for MinGW
*-config
scripts to match the
pkg-config
names
added
--cflags-only-I
and
--cflags-only-other
options to
misc/ncurses-config.in
Portability
Many of the portability changes are implemented via the configure script:
disallow configure options which apply only to multiuser systems, to improve ports to single-user systems such as Haiku
add warning to configure script to address conflict between the
--enable-lp64
option and the options for overriding the types used for
chtype
and
mmask_t
modify configure script cases for $host_os, to accommodate 64-bit big-endian POWER Linux with glibc
modify configure script and misc/Makefile to accept glob expressions that include Windows/DOS drive-letters
change
Ada95/configure
to use
--with-screen
option rather than
--enable-widec
, to provide more choices of underlying curses library.
modify configure script to work around broken gnatgcc script found in gcc-13 builds.
Other portability fixes include:
improve pattern used for configure
--with-xterm-kbs
option.
modify recursive make rules to avoid interference with GNU make's "-j" option
when installing the terminfo database, check if symbolic links are supported before attemping to link lib/terminfo from share/terminfo
improve logic in misc/run_tic.in for constructing symbolic link when
$DESTDIR
is set.
build-fix for ncurses-examples with newer PDCurses, which no longer has stubs for unimplemented features.
change
etip.h.in
to include either/both of

and

, needed for another old BSD.
correct conditional-compile for a case when the C compiler does not have a bool type.
improve
MKlib_gen.sh
handling of “bool” type, for building link_test.
modify
ncurses/tinfo/MKfallback.sh
to work with MacOS
sed
, which lacks BSD-style
\<
and
\>
modify
MKlib_gen.c
to allow for Solaris's definition of
NULL
as
0L
widen pattern in pc/*-config scripts to disallow more linker options.
avoid redefining bool in
curses.h
if the platform already supports that type.
move include

from
etip.h.in
to
cursesw.h
, to work around breakage in Apple's port of ncurses.
Features of
ncurses
The
ncurses
package is fully upward-compatible with SVr4 (System V Release 4) curses:
All of the SVr4 calls have been implemented (and are documented).
ncurses
supports the features of SVr4 curses including keyboard mapping, color, form drawing with ACS characters, and automatic recognition of keypad and function keys.
ncurses
provides work-alike replacements of SVr4 supplemental libraries based on curses, but which were not specified by X/Open Curses:
the panel library, permitting windows to stack and overlap
the menu library, supporting a uniform but flexible interface for menu programming
the form library, supporting data collection through on-screen forms
ncurses
's terminal database is fully compatible with that used by SVr4 curses.
ncurses
supports user-defined capabilities that it can see, but which are hidden from SVr4 curses applications using the
same
terminal database.
It can be optionally configured to match the format used in related systems such as AIX and Tru64.
Alternatively,
ncurses
can be configured to use hashed databases rather than the directory of files used by SVr4 curses.
The
ncurses
utilities have options to allow you to filter terminfo entries for use with less capable
curses
terminfo
versions such as the HP-UX and AIX ports.
The
ncurses
package also has many useful extensions over SVr4:
The API is 8-bit clean and base-level conformant with the X/Open Curses specification, XSI curses (that is, it implements all
BASE
level features, and almost all
EXTENDED
features). It includes many function calls not supported under SVr4 curses (but portability of all calls is documented so you can use the SVr4 subset only).
Unlike SVr3 curses,
ncurses
can write to the rightmost-bottommost corner of the screen if your terminal has an insert-character capability.
Ada95 and C++ bindings.
Support for mouse event reporting with X Window xterm and FreeBSD and OS/2 console windows.
Extended mouse support via Alessandro Rubini's gpm package.
The function
wresize
allows you to resize windows, preserving their data.
The function
use_default_colors
allows you to use the terminal's default colors for the default color pair, achieving the effect of transparent colors.
The functions
keyok
and
define_key
allow you to better control the use of function keys, e.g., disabling the
ncurses
KEY_MOUSE, or by defining more than one control sequence to map to a given key code.
Support for direct-color terminals, such as modern xterm.
Support for 256-color terminals, such as modern xterm.
Support for 16-color terminals, such as
aixterm
and
modern xterm
Better cursor-movement optimization. The package now features a cursor-local-movement computation more efficient than either BSD's or System V's.
Super hardware scrolling support. The screen-update code incorporates a novel, simple, and cheap algorithm that enables it to make optimal use of hardware scrolling, line-insertion, and line-deletion for screen-line movements. This algorithm is more powerful than the 4.4BSD curses
quickch
routine.
Real support for terminals with the magic-cookie glitch. The screen-update code will refrain from drawing a highlight if the magic- cookie unattributed spaces required just before the beginning and after the end would step on a non-space character. It will automatically shift highlight boundaries when doing so would make it possible to draw the highlight without changing the visual appearance of the screen.
It is possible to generate the library with a list of pre-loaded fallback entries linked to it so that it can serve those terminal types even when no terminfo tree or termcap file is accessible (this may be useful for support of screen-oriented programs that must run in single-user mode).
The
tic
captoinfo
utility provided with
ncurses
has the ability to translate many termcaps from the XENIX, IBM and AT&T extension sets.
A BSD-like
tset
utility is provided.
The
ncurses
library and utilities will automatically read terminfo entries from $HOME/.terminfo if it exists, and compile to that directory if it exists and the user has no write access to the system directory. This feature makes it easier for users to have personal terminfo entries without giving up access to the system terminfo directory.
You may specify a path of directories to search for compiled descriptions with the environment variable TERMINFO_DIRS (this generalizes the feature provided by TERMINFO under stock System V.)
In terminfo source files, use capabilities may refer not just to other entries in the same source file (as in System V) but also to compiled entries in either the system terminfo directory or the user's $HOME/.terminfo directory.
The table-of-entries utility
toe
makes it easy for users to see exactly what terminal types are available on the system.
X/Open Curses permits most functions it specifies to be made available as macros as well. ncurses does this
to improve performance, e.g., for operations composed of simpler functions such as cursor movement following by adding text to the screen,
to simplify the implementation by reusing functions which use common parameters, e.g., the standard screen
stdscr
, and
to provide functions that return values via their parameters
Except for the last case, ncurses provides a non-macro implementation of the function. If the macro definition is disabled with
#undef
, or by defining
NCURSES_NOMACROS
the function may be linked (and its calls will be checked against the prototype).
Extensive documentation is provided (see the
Additional Reading
section of the
ncurses
FAQ
for online documentation).
Applications using
ncurses
The
ncurses
distribution includes a selection of test programs (including a few games). These are available separately as
ncurses-examples
The ncurses library has been tested with a wide variety of applications including:
aptitude
FrontEnd to Apt, the debian package manager
cdk
Curses Development Kit
ded
directory-editor
dialog
the underlying application used in Slackware's setup, and the basis for similar install/configure applications on many systems.
lynx
the text WWW browser
mutt
mail utility
ncftp
file-transfer utility
nvi
New vi uses ncurses.
ranger
A console file manager with VI key bindings in
Python
tin
newsreader, supporting color, MIME
vifm
File manager with vi like keybindings
as well as some that use
ncurses
for the terminfo support alone:
minicom
terminal emulator for serial modem connections
mosh
a replacement for
ssh
tack
terminfo action checker
tmux
terminal multiplexor
vile
vi-like-emacs
may be built to use the terminfo, termcap or curses interfaces.
and finally, those which use only the termcap interface:
emacs
text editor
less
The most commonly used
pager
(a program that displays text files).
screen
terminal multiplexor
vim
text editor
Development activities
Zeyd Ben-Halim started
ncurses
from a previous package pcurses, written by Pavel Curtis. Eric S. Raymond continued development. Jürgen Pfeifer wrote most of the form and menu libraries.
Ongoing development work is done by
Thomas E. Dickey
. Thomas E. Dickey has acted as the maintainer for the Free Software Foundation, which held a
copyright on ncurses
for releases 4.2 through 6.1. Following the release of ncurses 6.1, effective as of release 6.2, copyright for ncurses reverted to Thomas E. Dickey (see the
ncurses FAQ
for additional information).
Contact the current maintainers at
bug-ncurses@gnu.org
To join the ncurses mailing list, please write email to
bug-ncurses-request@gnu.org
containing the line:
@
This list is open to anyone interested in helping with the development and testing of this package.
Beta versions of
ncurses
are made available at
and
Patches to the current release are made available at
and
There is an archive of the mailing list here:
Related resources
The release notes make scattered references to these pages, which may be interesting by themselves:
ncurses
licensing
Symbol versioning in
ncurses
Comments on
ncurses
versus
slang
(S-Lang)
Comments on
OpenBSD
tack – terminfo action checker
tctest – termcap library checker
Terminal Database
Other resources
The distribution provides a newer version of the terminfo-format terminal description file once maintained by
Eric Raymond
. Unlike the older version, the termcap and terminfo data are provided in the same file, which also provides several user-definable extensions beyond the X/Open Curses specification.
You can find lots of information on terminal-related topics not covered in the terminfo file in
Richard Shuford's archive
original
). The collection of computer manuals at
bitsavers.org
has also been useful.
(top)
Overview
Release Notes
Library improvements
Terminal driver
Other improvements
Program improvements
Utilities
Examples
Terminal database
Documentation
Interesting bug-fixes
Configuration changes
Major changes
Configuration options
Package configuration scripts
Portability
Features of
ncurses
Applications using
ncurses
Development activities
Related resources
Other resources
Older Releases