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ncurses 6.3

From: Thomas Dickey
Subject: ncurses 6.3
Date: Mon, 8 Nov 2021 18:50:07 -0500
User-agent: Mutt/1.10.1 (2018-07-13)

                            Announcing ncurses 6.3


   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

   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
     * 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,
     * 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
     * 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 via anonymous FTP at the GNU distribution site .

Release Notes

   These notes are for ncurses 6.3, released October 21, 2021.

   This  release  is  designed  to  be source-compatible with ncurses 5.0
   through  6.2; 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,  of  course,  numerous  other improvements, listed in this

   The  most  important  bug-fixes/improvements  dealt  with  portability
   issues.  The  release notes also mention some other bug-fixes, but are
   focused  on  new  features and improvements to existing features since
   ncurses 6.2 release.

  Library improvements

    New features

   There are a few new features:
     * A   new   (experimental)   driver,   for   the   Windows  Terminal
       configuration is provided.
     * A  script is provided which enables OpenBSD users to upgrade their
       system  to use ncurses 6.3 (OpenBSD developers are also invited to
       do this).

   Additionally,  to  improve  performance other changes (and extensions)
   are provided in this release:
     * modify  lib_mouse.c  to  check  for  out-of-range  button numbers,
       convert those to position reports.
     * add sp-funcs for erasewchar, killwchar.

    Other improvements

   These are revised features:
     * modify  wgetnstr,  wgetn_wstr  to  improve compatibility with SVr4
       curses in its treatment of interrupt and quit characters

   These were done to limit or ultimately deprecate features:
     * mark wgetch-events feature as deprecated.
          + prevent  KEY_EVENT  from  appearing  in  curses.h  unless the
            configure option --enable-wgetch-events is used.
          + modify   to   hide   ncurses'  definition  of
            KEY_EVENTS to reduce Visual Studio C++ redefinition warnings.
     * reduce   build-warnings   by   excluding   ncurses-internals  from
       deprecation warnings.

   These are improvements to existing features:
     * drop symbols GCC_PRINTF and GCC_SCANF from <curses.h>, to simplify
     * apply  gcc  format  attribute  to  prototypes  which use a va_list
       parameter rather than a "..." variable-length parameter list.
     * modify  <term.h> so that it is not necessary to include <curses.h>
       before <term.h>.
     * provide for wide-characters as background character in wbkgrnd
     * improve parameter-checking for tparm, adding function _nc_tiparm()
       to   handle   the  most-used  case,  which  accepts  only  numeric
     * use  return-value  from vsnprintf to reallocate as needed to allow
       for buffers larger than the screen size.
     * add  another  fflush(stdout) in _nc_flush to handle time-delays in
       the  middle  of  strings  such  as flash when the application uses
       low-level calls rather than curses.

   These are corrections to existing features:
     * add  a  check  to  guard against repeat_char emitting digits which
       could  be interpreted as BSD-style padding when --enable-bsdpad is
     * check  for screen size-change in scr_init and scr_restore, in case
       a screen dump does not match the current screen dimensions

  Program improvements

   Several improvements were made to the utility programs:


          + implement "+m" option


          + add check for duplicate "use=" clauses.
          + add  check  to  report  instances where tparm would detect an
            error in an expression.
          + add  user-defined  capabilities  from mintty to Caps-ncurses,
            for checking consistency.
          + improve warning when oc/op do not mention SGR 39/49 for xterm
            compatible XT flag.
          + improve  checks  for  number  of  parameters of smglp, smgrp,
            smgtp, and smgbp.
          + improve  "-c"  option  to  validate  the  number  and type of
            parameters  and  compare  against expected number/type before
            deciding which set of parameter-lists to use in tparm calls.
          + improve check for errors detected in tparm.
          + improve format of output, to ensure that the messages contain
            only printable text.
          + modify to eliminate unnecessary "\" to escape ":" in terminfo
          + remove check that assumes that none or both parameterized and
            non-parameterized margin-setting capabilities are present.


          + modify  output  of  "toe -as" to show first description found
            rather than the last.
          + add  a  check  to ensure that a "termcap file" is text rather
            than binary.


          + modify to allow multiple commands per line.
          + improve  parameter-checking  by analyzing all extended string
            capabilities,  e.g., as used in the Cs and Ms capabilities of
            the tmux description.
          + make  warning  messages  consistently  using alias names when
            those are used, rather than the underlying program's name.
          + improve   usage   message  for  aliases  such  as  clear,  by
            eliminating tput-specific portions.
          + modify  initialization  to  avoid  opening /dev/tty for cases
            other than reset/init, e.g., for clear.


   Along  with  the  library and utilities, improvements were made to the
   ncurses-examples.  Most  of  this  activity  aimed  at  improving  the
   test-packages.  A few changes are more generally useful, e.g., for the
   main   ncurses  test-program,  and  for  analyzing  traces  using  the
   tracemunch script:
     * add  "-r" option to the dots test-programs, to help with scripting
       a performance comparison.
     * build-fix  for  test_opaque,  for  configurations  without  opaque
       curses structs, e.g., ncurses 5.7.
     * improve tracemunch logic for "RUN" compaction.
     * improve tracemunch's coverage of form/menu/panel libraries.
     * improve  tracemunch's  checking/reporting  the  type for the first
       parameter, e.g., "WINDOW*" rather than "#1".
     * modify  tracemunch  and  the panel library to show readable traces
       for panel- and user-pointers.

   There are other new demo/test programs and reusable examples:

          to exercise the wide-character background functions.

          to  demonstrate move_field, and a stub for a corresponding demo
          of dup_field.

          for checking tparm changes.

  Terminal database

   There are several new terminal descriptions:

     absolute,    att610+cvis,    foot,    foot-direct,   hp98550-color,
     hpterm-color2,   hterm,   hterm-256color,   linux-s,  putty+keypad,
     putty+screen,    putty-screen,    screen.linux-s,   scrt/securecrt,
     tmux-direct,  vt220+cvis,  vt220+cvis8, vt220+pcedit, vt220+vtedit,
     vt220-base,     vt52+keypad,    xterm+256color2,    xterm+88color2,
     xterm-direct16,       xterm-direct256,      xterm+nofkeys,      and

   There  are  many  changes to existing terminal descriptions. Some were
   updates to several descriptions:
     * correct use-ordering in some xterm-direct flavors
     * fix   some   sgr   inconsistencies  in  d230c,  ibm6153,  ibm6154,
     * improve vt50h and vt52 based on DECScope manual
     * use hp+arrows in a few places
     * use hp+pfk-cr in a few places
     * use  vt220+cvis  in  st,  terminology,  termite  since they ignore
       blinking-cursor detail in att610+cvis

   while  others  affected specific descriptions. These were retested, to
   take into account changes by their developers:

     kitty+common, mlterm3, ms-terminal

   while  these are specific fixes based on reviewing documentation, user
   reports, or warnings from tic:

   aaa+dec, aaa+rv
          correct rmacs/smacs

          correct sgr

          correct csr

          use att610+cvis, xterm+tmux and ansi+enq

          re-enable "bel"

          fix pound-sign mapping in acsc

          modify to reflect default mapping of shift-tab by kbd 1.14

          fill in some missing pieces, to make it comparable to the vt220

          use vt100+fnkeys, add rep

          use vt100+enq

          corrected tsl capability

          correct cup

          change kbs to ^?

          use vt220+cvis

          add smglp and smgrp

          use vt420+lrmm

          add nel

          use vt52+keypad

   A few entries use extensions (user-defined terminal capabilities):
     * add   shifted   Linux  console  keys  in  linux+sfkeys  entry  for
     * add Smulx to alacritty
     * add kbeg to xterm+keypad to accommodate termcap applications
     * add  extensions  in  xterm+tmux and ecma+strikeout to ms-terminal,
       but cancel the non-working Cr and Ms capabilities


   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:
          + make  opts  extension  for  getcchar  work  as documented for
            ncurses 6.1, adding "-g" flag to demo_new_pair to illustrate.
          + modify  tset  "-q"  option to refrain from modifying terminal
            modes, to match the documentation.
     * New/improved history and portability sections:
          + improve documentation for tparm and static/dynamic variables.
          + add   history   note  to  curs_scanw.3x  for  <stdarg.h>  and
          + add   history  note  to  curs_printw.3x  for  <stdarg.h>  and
          + add portability note to ncurses.3x regarding <stdarg.h>
          + add   historical   notes   to   tput,   curses-terminfo   and
            curses-color manpages based on source-code for SVr2, SVr3 and
          + improve  history  section  for tset manpage based on the 1BSD
            tarball,  which  preceded  BSD's  SCCS  checkins by more than
            three years.
     * Other improvements:
          + explain  in ncurses.3x that functions in the tinfo library do
            not rely upon wide-characters.
          + improve   manual   page  for  panel  library,  extending  the
            portability section as well as documenting error-returns.
          + add  section  on  margins  to terminfo.5, adapted from X/Open
          + improve man/term.5 section on legacy storage format.
          + add a note in terminfo.5 explaining that no-parameter strings
            such as sgr0 or cnorm should not be used with tparm.
          + improve description of BSD-style padding in curs_termcap.3x
          + improve  discussion  of  padding  versus  tparm  and tputs in
          + add a note in manual page to explain ungetch vs unget_wch.
          + improve  description  of error-returns in waddch and waddnstr
            manual pages.

   There  are  no new manual pages (all of the manual page updates are to
   existing pages).

   Some  of  the  improvements  are  more subtle, relating to the way the
   information  is  presented. For instance, hyphenation is suppressed in
   the HTML files generated from manual pages because an upgrade to groff
   gave  noticeably  poorer  results,  interfering  with  the  process of
   creating links between the resulting webpages.

  Interesting bug-fixes

   While  there  were  many bugs fixed during development of ncurses 6.3,
   only  a  few  (the  reason  for  this release) were both important and
   interesting. Most of the bug-fixes were for local issues which did not
   affect  compatibility across releases. Since those are detailed in the
   NEWS file no elaboration is needed here.

   The interesting bugs were:
     * modify wbkgd and wbkgrnd to avoid storing a null in the background
       character, because it may be used in cases where the corresponding
       0x80 is not treated as a null.
       This  was  a regression introduced in ncurses 6.2 (reported on the
       mailing list), for which the workaround was to specify a blank for
       the background character.
     * remove  output-related  checks  for  nl/nonl (also reported on the
       mailing list).
     * improve  tparm  implementation of %P and %g, more closely matching
       SVr4  terminfo.  Those  denote  static  and  dynamic  variables in
       terminfo expressions.
       Exactly  what those terms meant was never documented before in any
       implementation of curses, aside from source code. Unlike the other
       two  fixes,  the  problem  was discovered while studying OpenBSD's
       version of tset.

  Configuration changes

    Major changes

   There  are  no  major  changes. Several new options were added to ease
   integration  of packages with systems using different versions of GNAT
   and ncurses. Also, improvements were made to configure checks.

    Configuration options

   There are a few new/modified configure options:

          new  configure  option  and  check  for gcc -fvisibility=hidden

          corrected  to allow turning leak-checking off later in a set of

          new  configure  option  makes the _Noreturn keyword optional to
          ease transition.

          revised option also controls whether $LDFLAGS from the build is
          provided in "-config" and ".pc" files.

          add  configure  option  which  tells  ncurses  to disallow most
          file-opens by setuid processes.

          changed  default  to  help  packagers  who  reuse wide ncursesw
          header file with non-wide ncurses library.

          revised  option  uses the actual search path from pkg-config or
          pkgconf using the output from --debug.

          new several --with-xxx-libname options, to help with pkgsrc


   Many  of  the  portability  changes  are implemented via the configure
     * add  a  special case in the configure script to work around one of
       the build-time breakages reported for OpenBSD 6 here:
     * modify configure check for libtool to prevent accidental use of an
       OpenBSD program which uses the same name.
     * modify  configuration  checks  for  build-time  tic/infocmp to use
       AC_CHECK_TOOL. That can still be overridden by --with-tic-path and
       --with-infocmp-path when fallbacks are used, but even if not using
       fallbacks, the improved check may help with cross-compiling.
     * relax modification-time comparison in CF_LINK_FUNCS to allow it to
       accept link() function with NFS filesystems which change the mtime
       on the link target, e.g., several BSD systems.
     * modify  configure  check  for  c89/c99 aliases of clang to use its
       -std  option instead, because some platforms, in particular macOS,
       do not provide workable c89/c99 aliases.
     * modify  CF_NCURSES_CONFIG  to work around Xcode's c99 "-W" option,
       which conflicts with conventional use for passing linker options.
     * modify   configure   scripts   to   filter  out  redefinitions  of
       _XOPEN_SOURCE,  e.g., for NetBSD which generally supports 500, but
       600 is needed for ncursesw.

   Here are some of the other portability fixes:
     * change   configure-check   and   source-code  for  gcc's  noreturn
       attribute  to  assume  it is a prefix rather than suffix, matching
       c11's _Noreturn convention.
     * modify mk-1st.awk to account for extra-suffix configure option.
     * build-fix for termsort module when configured with termcap.
     * modify  configure  script  and  makefiles to support ".PHONY" make
       program feature.
     * amend  libtool  configuration  to  add dependency for install.tic,
       etc., in ncurses/Makefile on the lower-level libraries.
     * modify Ada95 source-generation utility to write to a file given as
       parameter rather than to the standard output, allowing builds with
     * amend  tic/infocmp  check  to  allow  for  the  respective  tool's
     * build-fixes for gnat 10.1.1, whose gnatmake drops integration with
     * correct configure version-check/warning for g++ to allow for 10.x

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  all  of  the for SVr4 curses features including
       keyboard  mapping,  color,  forms-drawing with ACS characters, and
       automatic recognition of keypad and function keys.
     * ncurses  provides  these SVr4 add-on libraries (not part of X/Open
          + the  panels  library,  supporting  a  stack  of  windows with
            backing store.
          + the   menus   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 which 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
     * 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  most  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
     * 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
     * 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
     * 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
     * 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.
     * The library meets the XSI requirement that every macro entry point
       has  a  corresponding  function  which  may be linked (and will be
       prototype-checked)  if  the  macro  definition  is  disabled  with
     * 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

   The   ncurses   library  has  been  tested  with  a  wide  variety  of
   applications including:

          FrontEnd to Apt, the debian package manager

          Curses Development Kit


          the  underlying  application used in Slackware's setup, and the
          basis   for  similar  install/configure  applications  on  many

          the text WWW browser

          mail utility

          file-transfer utility

          New vi uses ncurses.

          A console file manager with VI key bindings in Python.

          newsreader, supporting color, MIME

          File manager with vi like keybindings

   as well as some that use ncurses for the terminfo support alone:

          terminal emulator for serial modem connections

          a replacement for ssh.

          terminfo action checker

          terminal multiplexor

          vi-like-emacs  may  be  built  to  use the terminfo, termcap or
          curses interfaces.

   and finally, those which use only the termcap interface:

          text editor

          The  most  commonly  used  pager  (a program that displays text

          terminal multiplexor

          text editor

Development activities

   Zeyd  Ben-Halim  started  ncurses  from  a  previous  package pcurses,
   written  by  Pavel  Curtis.  Eric  S.  Raymond  continued development.
   Juergen 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

   To join the ncurses mailing list, please write email to

   containing the line:

     subscribe <name>@<host.domain>

   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: (also https)

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 specification.

   You  can  find  lots  of  information  on  terminal-related topics not
   covered  in  the  terminfo  file  at  Richard  Shuford's archive . The
   collection of computer manuals at has also been useful.

     * Overview
     * Release Notes
          + Library improvements
               o New features
               o Other improvements
          + Program improvements
               o Utilities
               o Examples
          + Terminal database
          + Documentation
          + Interesting bug-fixes
          + Configuration changes
               o Major changes
               o Configuration options
          + Portability
     * Features of ncurses
     * Applications using ncurses
     * Development activities
     * Related resources
     * Other resources

Thomas E. Dickey <>

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