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:
The distribution includes the library and support utilities, including
Full manual pages are provided for the library and tools.
The ncurses distribution is available at ncurses' homepage:
https://invisible-island.net/archives/ncurses/ or
https://invisible-mirror.net/archives/ncurses/ .
It is also available at the GNU distribution site
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.
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
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
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 mallocs 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
Several improvements were made to the utility programs.
improved infocmp -E/-e fallback feature
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
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
Warn about capabilities which expect parameters where none are given. Also, repair the feature where multiple capabilities can be handled on a single line.
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:
Shows a chart of the first 256 character codes, which are not as consistent across platforms for ctype versus wctype as some suppose.
There are several new terminal descriptions:
illumos, sun-16color, sun-256color, and sun-direct
along with building blocks
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
improve use-clauses: ansi+cup, ansi+idl1, ansi+rca, ansi+rca2, ansi+sgrso, ansi+sgrul
sclp:
update ms-terminal
update st to 0.8.5
update teraterm to 5.0
update foot to 1.18.1
update iTerm2 to 3.5.0
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).
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 <sys/fsuid.h>, 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 <new> 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.
There are a few new configure options:
Modify behavior of $DESTDIR to merge or replace the value set by --prefix.
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:
This option is obsolete, replaced by --enable-named-pipes.
This is enabled by default on platforms where the Windows driver can be compiled, e.g., Cygwin, MinGW32 and MSYS2.
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
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 <new> and <exception>, 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 <curses.h> from etip.h.in to cursesw.h, to work around breakage in Apple's port 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 make