- ncurses
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ncurses 
ncurses-based menuconfigDeveloper(s) GNU Project Stable release 5.9 / 4 April 2011 Operating system POSIX Type Widget toolkit License MIT license Website www.gnu.org/software/ncurses/ncurses.html ncurses (new curses) is a programming library that provides an API which allows the programmer to write text user interfaces in a terminal-independent manner. It is a toolkit for developing "GUI-like" application software that runs under a terminal emulator. It also optimizes screen changes, in order to reduce the latency experienced when using remote shells.
Contents
History
The N in ncurses comes from the word new. This is because ncurses is a free software emulation (clone) of the System V Release 4.0 (SVr4) curses, which was itself an enhancement over the discontinued classic 4.4 BSD curses.[1] The XSI Curses standard issued by X/Open is explicitly and closely modeled on System V.
curses
The first curses library was developed at the University of California at Berkeley, for a BSD operating system, around 1980 to support a screen-oriented game. It originally used the termcap library, which was used in other programs, such as the vi editor.[1]
The success of the BSD curses library prompted Bell Labs to release an enhanced curses library in their System III and System V Release 1 Unix systems. This library was more powerful and instead of using termcap, it used terminfo. However, due to AT&T policy regarding source-code distribution, this improved curses library did not have much acceptance in the BSD community.[1]
pcurses
Around 1982, Pavel Curtis started work on a freeware clone of the Bell Labs curses, named pcurses, which was maintained by various people through 1986.[2]
ncurses
The pcurses library was further improved when Zeyd Ben-Halim took over the development effort in late 1991.[1][2][3] The new library was released as ncurses in November 1993, with version 1.8.1 as the first major release. Subsequent work, through version 1.8.8 (1995), was driven by Eric S. Raymond, who added the form and menu libraries written by Juergen Pfeifer.[4] Since 1996, it has been maintained by Thomas E. Dickey.[2]
Most ncurses calls can be easily ported to the old curses. System V curses implementations can support BSD curses programs with just a recompilation.[5] However, a few areas are problematic, such as handling terminal resizing, since no counterpart exists in the old curses.
Terminal database
Ncurses can use either terminfo (with extensible data) or termcap. Other implementations of curses generally use terminfo; a minority use termcap. Few (mytinfo was an older exception[6]) use both.
License
Ncurses is a part of the GNU Project. It is one of the few GNU files not distributed under the GNU GPL or LGPL; it is distributed under a permissive free software licence, similar to the MIT License.[7] This is due to the agreement made with the Free Software Foundation at the time the developers assigned their copyright.
When the agreement was made to pass on the rights to the FSF, there was a clause that stated
"The Foundation promises that all distribution of the Package, or of any work "based on the Package", that takes place under the control of the Foundation or its agents or assignees, shall be on terms that explicitly and perpetually permit anyone possessing a copy of the work to which the terms apply, and possessing accurate notice of these terms, to redistribute copies of the work to anyone on the same terms".[7]
According to the maintainer Thomas E. Dickey, this precludes relicensing to the GPL in any version, since it would place restrictions on the programs that will be able to link to the libraries.[7]
However, because it is Free Software Foundation software, they may choose to GPL it in the future.[8]
Programs using ncurses
There are hundreds of programs which use ncurses.[9][10] Some, such as GNU Screen and w3m, use only the termcap interface, performing screen management within the application. Others, such as GNU Midnight Commander and YaST use the curses programming interface.
See also
- SMG$. The Screen Management library available under OpenVMS.
- conio. A C header file used in MS-DOS compilers to create text user interfaces.
- Curses Development Kit
- Dialog (software)
References
- ^ a b c d Eric S. Raymond (September 1995). "ncurses: Portable Screen-Handling for Linux". Linux Journal. http://www.linuxjournal.com/article/1124.
- ^ a b c Thomas E. Dickey (December 1996). "NCURSES - New Curses". http://invisible-island.net/ncurses/.
- ^ The README file in ncurses 1.8.1 states "v0.1 July 31, 1992" and "v1.8.1 November 5, 1993", which agrees with the NEWS (changelog) file
- ^ NCURSES - Frequently Asked Questions (FAQ): Who wrote NCURSES?
- ^ A Hacker's Guide to Ncurses Internals
- ^ Ross Ridge (December 27, 1992). "mytinfo posting to comp.sources.unix newsgroup". Internet Systems Consortium, Inc. http://www.isc.org/index.pl?/sources/utils/terminal/mytinfo.php.
- ^ a b c NCURSES - Frequently Asked Questions (FAQ): Is it GPL'd?
- ^ NCURSES - Frequently Asked Questions (FAQ): Will it ever be GPL?
- ^ "Search results: +ncurses". freshmeat.net. http://freshmeat.net/search/?q=ncurses§ion=projects&Go.x=0&Go.y=0.
- ^ "Projects tagged ‘ncurses’". ohloh. http://www.ohloh.net/tags/ncurses.
External links
Programming Introductions
- Introduction "Writing Programs with NCURSES" by Eric S. Raymond and Zeyd M. Ben-Halim
- ncurses Programming HOWTO ( and PDF version)
- ncurses Beginner's Tutorial
- A Hacker's Guide to NCURSES
Toolkits
- NDK++ Development Kit for C++
Language bindings
- Ada95 Binding
- Binding for C#
- Binding for ANSI Common Lisp
- Binding for GNU Guile
- Binding for Haskell
- Binding for Java
- Binding for JavaScript
- Binding for Perl
- Terminal Screen Control Functions for PHP
- Binding for Python
- Ruby module
- Binding for Go
- Binding for Node.js
- Free Pascal Binding
Distributions and packages
Categories:- GNU Project software
- Curses (programming library)
- Terminfo
- Termcap
- Software using the MIT license
- Free software programmed in Ada
- Free software programmed in C
- C libraries
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