# Announcing ncurses 5.6

The ncurses (new curses) library is a free software emulation of curses in System V Release 4.0, 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 SYSV-curses enhancements over BSD 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.

The ncurses code was developed under GNU/Linux. It has been in use for some time with OpenBSD as the system curses library, and on FreeBSD and NetBSD as an external package. It should port easily to any ANSI/POSIX-conforming UNIX. It has even been ported to OS/2 Warp!

The distribution includes the library and support utilities, including a terminfo compiler tic(1), a decompiler infocmp(1), clear(1), tput(1), tset(1), and a termcap conversion tool captoinfo(1). Full manual pages are provided for the library and tools.

The ncurses distribution is available via anonymous FTP at the GNU distribution site ftp://ftp.gnu.org/gnu/ncurses/ .
It is also available at ftp://invisible-island.net/ncurses/ .

# Release Notes

This release is designed to be upward compatible from ncurses 5.0 through 5.5; very few applications will require recompilation, depending on the platform. These are the highlights from the change-log since ncurses 5.5 release.

Interface changes:

- generate linkable stubs for some macros:
  getbegx, getbegy, getcurx, getcury, getmaxx, getmaxy, getparx, getpary, getpary,
  and (for libncursesw)
  wgetbkgrnd

New features and improvements:

- library
  - support hashed databases for the terminal descriptions. This uses the Berkeley database, has been tested for several versions on different platforms.
  - add `use_legacy_coding()` function to support lynx's font-switching feature.
  - add extension `nofilter()`, to cancel a prior `filter()` call.
  - add/install a package config script, e.g., `ncurses5-config` or `ncursesw5-config`, according to configuration options.
  - provide ifdef for `NCURSES_NOMACROS` which suppresses most macro definitions from curses.h, i.e., where a macro is defined to override a function to improve performance.
  - make ifdef's consistent in `curses.h` for the extended colors so the header file can be used for the normal curses library. The header file installed for extended colors is a variation of the wide-character configuration.
  - improve `tgetstr()` by making the return value point into the user's buffer, if provided.
  - add ifdef's allowing ncurses to be built with `tparm()` using either varargs (the existing status), or using a fixed-parameter list (to match X/Open).
  - widen the test for xterm `kmous` a little to `allow` for other strings than "\E[M", e.g., for `xterm-sco` functionality in xterm.
  - modify `wgetnstr()` to return `KEY_RESIZE` if a sigwinch occurs.
  - move prototypes for wide-character trace functions from curses.tail to curses.wide to avoid accidental reference to those if `_XOPEN_SOURCE_EXTENDED` is defined without ensuring that <wchar.h> is included.
  - change the way shared libraries (other than libtool) are installed. Rather than copying the build-tree's libraries, link the shared objects into the install directory. This makes the `--with-rpath` option work except with `$(DESTDIR)`.
  - several improvements for rendering in hpterm. These are only available if the library is configured using `--enable-xmc-glitch`.
  - Add `NCURSES_NO_HARD_TABS` and `NCURSES_NO_MAGIC_COOKIE` environment variables to allow runtime suppression of the related hard-tabs and xmc-glitch features.
- programs:
  - add new test programs: chgat.c, demo_altkeys.c, echochar.c, foldkeys.c, movewindow.c, redraw.c, (noting that existing test programs also were modified to test additional features).
  - modify tack to test extended capability function-key strings.
  - modify toe to access termcap data, e.g., via `cgetent()` functions, or as a text file if those are not available.
  - improve infocmp/tic `-f` option formatting.
  - add `toe -a` option, to show all databases. This uses new private interfaces in the ncurses library for iterating through the list of databases.
  - modify `MKfallback.sh` to use `tic -x` when constructing fallback tables to allow extended capabilities to be retrieved from a fallback entry.
- terminal database
  - add terminfo entries for xfce terminal (xfce) and multi gnome terminal (mgt)
  - add nsterm-16color entry
  - updated mlterm terminfo entry
  - add kon, kon2 and jfbterm terminfo entry
  - remove invis capability from klone+sgr, mainly used by linux entry, since it does not really do this
  - add ka2, kb1, kb3, kc2 to vt220-keypad as an extension
  - add shifted up/down arrow codes to xterm-new as kind/kri strings
  - add hpterm-color terminfo entry
  - add 256color variants of terminfo entries for programs which are reported to implement this feature
  - correct order of use-clauses in rxvt-basic entry which made codes for f1-f4 vt100-style rather than vt220-style.

Major bug fixes:

- correct a typo in configure `--with-bool` option for the case where `--without-cxx` is used.
- move assignment from environment variable `ESCDELAY` from `initscr()` down to `newterm()` so the environment variable affects timeouts for terminals opened with newterm() as well.
- modify `werase` to clear multicolumn characters that extend into a derived window.
- modify `wchgat()` to mark updated cells as changed so a refresh will repaint those cells.
- correct logic in `wadd_wch()` and `wecho_wch()`, which did not guard against passing the multi-column attribute into a call on `waddch()`, e.g., using data returned by `win_wch()`
- fix redrawing of windows other than `stdscr` using `wredrawln()` by touching the corresponding rows in `curscr`.
- reduce memory leaks in repeated calls to `tgetent()` by remembering the last `TERMINAL*` value allocated to hold the corresponding data and freeing that if the `tgetent()` result buffer is the same as the previous call.
- modify `read_termtype()` so the `term_names` data is always allocated as part of the `str_table`, a better fix for a memory leak.
- fix `wins_nwstr(),` which did not handle single-column non-8bit codes.
- modify `wbkgrnd()` to avoid clearing the `A_CHARTEXT` attribute bits since those record the state of multicolumn characters.
- improve `SIGWINCH` handling by postponing its effect during `newterm()`, etc., when allocating screens.
- remove 970913 feature for copying subwindows as they are moved in `mvwin()`.
- add checks in `waddchnstr()` and `wadd_wchnstr()` to stop copying when a null character is found.
- add some checks to ensure current position is within scrolling region before scrolling on a new line.
- add a workaround to ACS mapping to allow applications such as test/blue.c to use the "PC ROM" characters by masking them with A_ALTCHARSET. This worked up til 5.5, but was lost in the revision of legacy coding.

Portability:

- configure script:
  - new options:
    --with-hashed-db
      Use Berkeley hashed database for storing terminfo data rather than storing each compiled entry in a separate binary file within a directory tree.
    --without-dlsym
      Do not use `dlsym()` to load GPM dynamically.
    --with-valgrind
      Simplify building for testing with valgrind.
    --enable-wgetch-events
      Compile with experimental wgetch-events code.
    --enable-signed-char
      Store booleans in "signed char" rather than "char".
  - improved options:
    --disable-largefile
      make the option work both ways.
    --with-gpm
      The option now accepts a parameter, i.e., the name of the dynamic GPM library to load via `dlopen()`
    --disable-symlinks
      The option now allows one to disable `symlink()` in `tic` even when `link()` does not work.
- other configure/build issues:
  - remove special case for Darwin in `CF_XOPEN_SOURCE` configure macro.
  - add configure check to ensure that `SIGWINCH` is defined on platforms such as OS X which exclude that when `_XOPEN_SOURCE,` etc., are defined
  - use ld's `-search_paths_first` option on Darwin to work around odd search rules on that platform.
  - improve ifdef's for `_POSIX_VDISABLE` in tset to work with Mac OS X.
  - modify configure script to ensure that if the C compiler is used rather than the loader in making shared libraries, the `$(CFLAGS)` variable is also used.
  - use `${CC}` rather than `${LD}` in shared library rules for IRIX64, Solaris to help ensure that initialization sections are provided for extra linkage requirements, e.g., of C++ applications.
  - improve some shared-library configure scripting for Linux, FreeBSD and NetBSD to make `--with-shlib-version` work.
  - split up dependency of `names.c` and `codes.c` in `ncurses/Makefile` to work with parallel make.
  - modify `MKlib_gen.sh` to change preprocessor-expanded `_Bool` back to `bool`.
  - modify `progs/Makefile.in` to make `tput init` work properly with cygwin, i.e., do not pass a `.exe` in the reference string used in check_aliases.
- library:
  - ignore wide-acs line-drawing characters that `wcwidth()` claims are not one-column. This is a workaround for Solaris' broken locale support.
  - reduce name-pollution in `term.h` by removing `#define`'s for HAVE_xxx symbols.
  - fix `#ifdef` in `c++/internal.h` for QNX 6.1
- test programs:
  - modify `test/configure` script to allow building test programs with PDCurses/X11.
  - modified test programs to allow some to work with NetBSD curses. Several do not because NetBSD curses implements a subset of X/Open curses, and also lacks much of SVr4 additions. But it is enough for comparison.
  - improved `test/configure` to build test/ncurses on HPUX 11 using the vendor curses.
  - change configure script to produce `test/Makefile` from data file.

# Features of Ncurses

The ncurses package is fully compatible with SVr4 (System V Release 4) curses:

- All 257 of the SVr4 calls have been implemented (and are documented).
- Full support for SVr4 curses features including keyboard mapping, color, forms-drawing with ACS characters, and automatic recognition of keypad and function keys.
- An emulation of the SVr4 panels library, supporting a stack of windows with backing store, is included.
- An emulation of the SVr4 menus library, supporting a uniform but flexible interface for menu programming, is included.
- An emulation of the SVr4 form library, supporting data collection through on-screen forms, is included.
- Binary terminfo entries generated by the ncurses tic(1) implementation are bit-for-bit-compatible with the entry format SVr4 curses uses.
- The 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 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 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(1)/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(1) 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.
- A script (capconvert) is provided to help BSD users transition from termcap to terminfo. It gathers the information in a TERMCAP environment variable and/or a ~/.termcap local entries file and converts it to an equivalent local terminfo tree under $HOME/.terminfo.
- Automatic fallback to the /etc/termcap file can be compiled in when it is not possible to build a terminfo tree. This feature is neither fast nor cheap, you don't want to use it unless you have to, but it's there.
- 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 have a corresponding function which may be linked (and will be prototype-checked) if the macro definition is disabled with `#undef`.
- An HTML "Introduction to Programming with NCURSES" document provides a narrative introduction to the curses programming interface.

# State of the Package

Numerous bugs present in earlier versions have been fixed; the library is far more reliable than it used to be. Bounds checking in many `dangerous' entry points has been improved. The code is now type-safe according to gcc -Wall. The library has been checked for malloc leaks and arena corruption by the Purify memory-allocation tester.

The ncurses code has been tested with a wide variety of applications including (versions starting with those noted):

cdk
  Curses Development Kit
  http://invisible-island.net/cdk/
  http://www.vexus.ca/products/CDK/
ded
  directory-editor
  http://invisible-island.net/ded/
dialog
  the underlying application used in Slackware's setup, and the basis for similar applications on GNU/Linux.
  http://invisible-island.net/dialog/
lynx
  the character-screen WWW browser
  http://lynx.isc.org/release/
Midnight Commander
  file manager
  http://www.ibiblio.org/mc/
mutt
  mail utility
  http://www.mutt.org/
ncftp
  file-transfer utility
  http://www.ncftp.com/
nvi
  New vi versions 1.50 are able to use ncurses versions 1.9.7 and later.
  http://www.bostic.com/vi/
pinfo
  Lynx-like info browser. http://dione.ids.pl/~pborys/software/pinfo/
tin
  newsreader, supporting color, MIME http://www.tin.org/
vh-1.6
  Volks-Hypertext browser for the Jargon File
  http://www.debian.org/Packages/unstable/text/vh.html

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

minicom
  terminal emulator
  http://alioth.debian.org/projects/minicom/
vile
  vi-like-emacs
  http://invisible-island.net/vile/

The ncurses distribution includes a selection of test programs (including a few games).

## Who's Who and What's What

Zeyd Ben-Halim started it 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 work is being done by Thomas Dickey. Thomas Dickey acts as the maintainer for the Free Software Foundation, which holds the copyright on ncurses. 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:

                 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 and patches to the current release are made available at ftp://invisible-island.net/ncurses/ .

## Future Plans

- Extended-level XPG4 conformance, with internationalization support.
- Ports to more systems, including DOS and Windows.

We need people to help with these projects. If you are interested in working on them, please join the ncurses list.

## Other Related 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, and 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 .