Announcing ncurses 4.0
The ncurses (new curses) library is a freeware emulation of System V Release 4.0 curses. 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 is encouraging the keepers of Unix releases such as BSD/OS, freeBSD and netBSD to switch over to ncurses.
The ncurses code was developed under Linux. 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: ftp://ftp.netcom.com/pub/zm/zmbenhal/ncurses. It is also carried on the GNU distribution site at ftp://prep.ai.mit.edu/pub/gnu.
Features of ncurses
The ncurses package is fully compatible with SVr4 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 System V Release 4 panels library, supporting a stack of windows with backing store, is included.
- An emulation of the System V Release 4 menus library, supporting a uniform but flexible interface for menu programming, is included.
- An emulation of the System V Release 4 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, but not all EXTENDED features). Most EXTENDED-level features not directly concerned with wide-character support are implemented, including many function calls not supported under SVr4 curses (but portability of all calls is documented so you can use the SVr4 subset only).
- Unlike SVr4 curses, ncurses can write to the rightmost-bottommost corner of the screen if your terminal has an insert-character capability.
- (PC-clone boxes only) Support for access to the IBM PC ROM characters 0-32 through the highlight A_ALTCHARSET.
- Support for mouse event reporting under xterm.
- The function wresize() allows you to resize windows, preserving their data.
- 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:
- directory-editor ftp://ftp.clark.net/pub/dickey/ded.
- the underlying application used in Slackware's setup, and the basis for similar applications on Linux.
- the character-screen WWW browser
- ncftp 2.0
- file-transfer utility
- New vi versions 1.50 are able to use ncurses versions 1.9.7 and later.
- tape archive utility
- Volks-Hypertext browser for the Jargon File
as well as some that use ncurses for the terminfo support alone:
- terminal emulator
- tin (unofficial) newsreader, supporting color, MIME ftp://ftp.akk.uni-karlsruhe.de/pub/news/clients/tin-unoff.
- vi-like-emacs ftp://ftp.clark.net/pub/dickey/vile.
The ncurses distribution includes a selection of test programs (including a few games).
Who's Who and What's What
The original maintainer of ncurses is Zeyd Ben-Halim. Unfortunately, he can only work on the package part time. As a result, since 1.8.1, much of the enhancement work and documentation has been done by Eric S. Raymond. The current primary maintainers are Thomas Dickey and Juergen Pfeifer. However, requests for beta releases and other queries should properly be directed to Zeyd.
There is an ncurses mailing list. It is a majordomo list; to join, write to email@example.com with a message containing the line:
subscribe ncurses-list <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 ftp://ftp.clark.net/pub/dickey/ncurses.
- Extended mouse support via Alessandro Rubini's gpm package.
- 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.
The terminfo/termcap Database
The distribution includes and uses a copy of the terminfo-format terminal description file maintained by Eric Raymond. You can download either the termcap or terminfo versions of the terminal-type database from Eric's ncurses page, http://www.ccil.org/~esr/ncurses.html.
Other Related Resources
You can find lots of information on terminal-related topics not covered in the terminfo file at Richard Shuford's archive.