Announcing ncurses 5.7

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 5.6; very few applications will require recompilation, depending on the platform. These are the highlights from the change-log since ncurses 5.6 release.

Interface changes:

• generate linkable stubs for some macros:
  getattrs

New features and improvements:

• library
  • new flavor of the ncurses library provides rudimentary support for POSIX threads. Several functions are reentrant, but most require either a window-level or screen-level mutex.
    (This is API-compatible, but not ABI-compatible with the normal library).
  • add NCURSES_OPAQUE symbol to curses.h, will use to make structs opaque in selected configurations.
  • add NCURSES_EXT_FUNCS and NCURSES_EXT_COLORS symbols to curses.h to make it simpler to tell if the extended functions and/or colors are declared.
  • add wresize() to C++ binding
  • eliminate fixed-buffer vsprintf() calls in C++ binding.
  • add several functions to C++ binding which wrap C functions that pass a WINDOW* parameter.
  • adapt mouse-handling code from menu library in form-library
  • improve tracing for form library, showing created forms, fields, etc.
  • make $NCURSES_NO_PADDING feature work for termcap interface .
  • add check to trace-file open, if the given name is a directory, add ".log" to the name and try again.
  • several new manpages: curs_legacy.3x, curs_memleaks.3x, curs_opaque.3x and curs_threads.3x
• programs:
  • modified three test-programs to demonstrate the threading support in this version: ditto, rain, worm.
  • several new test-programs: demo_panels, dots_mvcur, inch_wide, inchs, key_name, key_names, savescreen, savescreen.sh test_arrays, test_get_wstr, test_getstr, test_instr, test_inwstr and test_opaque.
  • add adacurses-config to the Ada95 install.
  • modify tic -f option to format spaces as \s to prevent them from being lost when that is read back in unformatted strings.
  • The tack program is now distributed separately from ncurses.
• terminal database
  • added entries:
    • Eterm-256color, Eterm-88color and rxvt-88color
    • aterm
    • konsole-256color
    • mrxvt
    • screen.mlterm
    • screen.rxvt
    • teraterm4.59 is now the primary primary teraterm entry, renamed original to teraterm2.3
    • 9term terminal
    • Newbury Data entries
  • updated/improved entries:
    • gnome to version 2.22.3
    • h19, z100
    • konsole to version 1.6.6
    • mlterm, mlterm+pcfkeys
    • xterm, and building-blocks for function-keys to xterm patch #230.

Major bug fixes:

• add logic to tic for cancelling strings in user-defined capabilities (this is needed for current konsole terminfo entry).
• modify mk-1st.awk so the generated makefile rules for linking or installing shared libraries do not first remove the library, in case it is in use, e.g., libncurses.so by /bin/sh.
• correct check for notimeout() in wgetch().
• fix a sign-extension bug in infocmp's repair_acsc() function.
• change winnstr() to stop at the end of the line.
• make Ada95 demo_panels() example work.
• fix for adding a non-spacing character at the beginning of a line.
• fill in extended-color pair to make colors work for wide-characters using extended-colors.
• improve refresh of window on top of multi-column characters, taking into account split characters on left/right window boundaries.
• modify win_wchnstr() to ensure that only a base cell is returned for each multi-column character.
• improve waddch() and winsch() handling of EILSEQ from mbrtowc() by using unctrl() to display illegal bytes rather than trying to append further bytes to make up a valid sequence.
• restore curs_set() state after endwin()/refresh()
• modify keyname() to use "^X" form only if meta() has been called, or if keyname() is called without initializing curses, e.g., via initscr() or newterm().
• modify unctrl() to check codes in 128-255 range versus isprint(). If they are not printable, and locale was set, use a "M-" or "~" sequence.
• improve resizeterm() by moving ripped-off lines, and repainting the soft-keys.
• modify form library to accept control characters such as newline in set_field_buffer(), which is compatible with Solaris.
• use NCURSES_MOUSE_MASK() in definition of BUTTON_RELEASE(), etc., to make those work properly with the --enable-ext-mouse configuration
• correct some functions in Ada95 binding which were using return value from C where none was returned.
• reviewed/fixed issues reported by Coverity and Klocwork tools.

Portability:

• configure script:
  • new options:

    --disable-big-strings

    control whether static string tables are generated as single large strings (to improve startup performance), or as array of individual strings.

    --disable-relink

    control whether shared libraries are relinked (during install) when rpath is enabled.

    --disable-tic-depends

    make explicit whether tic library depends on ncurses/ncursesw library.

    --enable-mixed-case

    override the configure script's check if the filesystem supports mixed-case filenames. This allows one to control how the terminal database maps to the filesystem. For filesystems that do not support mixed-case, the library uses generate 2-character (hexadecimal) codes for the lower-level of the filesystem terminfo database

    --enable-reentrant

    builds a different flavor of the ncurses library (ncursest) which improves reentrant use of the library by reducing global and static variables (see the "--with-pthread" option for the threaded support).

    --enable-weak-symbols

    use weak-symbols for linking to the POSIX thread library, and use the same soname for the ncurses shared library as the normal library (caveat: the ABI is for the threaded library, which makes global data accessed via functions).

    --with-pthread

    build with the POSIX thread library (tested with AIX, Linux, FreeBSD, OpenBSD, HPUX, IRIX64, Solaris, Tru64).

    --with-ticlib

    build/install the tic-support functions in a separate library

  • improved options:

    --enable-ext-colors

    requires the wide-character configuration.

    --with-chtype

    ignore option value "unsigned" is always added to the type in curses.h; do the same for --with-mmask-t.

    --with-dmalloc

    build-fix for redefinition of strndup.

    --with-hashed-db

    accepts a parameter which is the install-prefix of a given Berkeley Database.

    --with-hashed-db

    the $LIBS environment variable overrides the search for the db library.

    --without-hashed-db

    assumed when "--disable-database" is used.

• other configure/build issues:
  • build-fixes for LynxOS
  • modify shared-library rules to allow FreeBSD 3.x to use rpath.
  • build-fix for FreeBSD "contemporary" TTY interface.
  • build-fixes for AIX with libtool.
  • build-fixes for Darwin and libtool.
  • modify BeOS-specific ifdef's to build on Haiku.
  • corrected gcc options for building shared libraries on Solaris and IRIX64.
  • change shared-library configuration for OpenBSD, make rpath work.
  • build-fixes for using libutf8, e.g., on OpenBSD 3.7
  • add "-e" option in ncurses/Makefile.in when generating source-files to force earlier exit if the build environment fails unexpectedly.
  • add support for shared libraries for QNX.
  • change delimiter in MKlib_gen.sh from '%' to '@', to avoid substitution by IBM xlc to '#' as part of its extensions to digraphs.
• library:
  • rewrite wrapper for wcrtomb(), making it work on Solaris. This is used in the form library to determine the length of the buffer needed by field_buffer.
  • add/use configure script macro CF_SIG_ATOMIC_T, use the corresponding type for data manipulated by signal handlers.
  • set locale in misc/ncurses-config.in since it uses a range
  • disable GPM mouse support when $TERM does not happen to contain "linux", since Gpm_Open() no longer limits its assertion to terminals that it might handle, e.g., within "screen" in xterm.
  • reset mouse file-descriptor when unloading GPM library.
• test programs:
  • update test programs to build/work with various UNIX curses for comparisons.

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 256-color terminals, such as modern xterm, when configured using the --enable-ext-colors option.
• 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. https://alioth.debian.org/projects/pinfo/

tin

newsreader, supporting color, MIME http://www.tin.org/

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 .