Ncurses 5.5 review
DownloadThe Ncurses (new curses) library is a free software emulation of curses in System V Release 4.0, and more. It uses Terminfo format,
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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.
The ncurses code was developed under GNU/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, a decompiler infocmp, clear, tput, tset, and a termcap conversion tool captoinfo. Full manual pages are provided for the library and tools.
Here are some key 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 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 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 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 XFree86 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 sets.
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 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.
What's New in This Release:
The forms and menus libraries work with multi-byte characters.
Experimental support for 256 color display and 5-button mice have been added.
Many improvements have been made to locale support and portability, as well as bugfixes in different areas.
Ncurses 5.5 keywords