<s>
ncurses	B-Language
(	O
new	B-Language
curses	I-Language
)	O
is	O
a	O
programming	B-Library
library	I-Library
providing	O
an	O
application	B-Application
programming	I-Application
interface	I-Application
(	O
API	B-Application
)	O
that	O
allows	O
the	O
programmer	O
to	O
write	O
text-based	B-Application
user	I-Application
interfaces	I-Application
(	O
TUI	O
)	O
in	O
a	O
terminal-independent	O
manner	O
.	O
</s>
<s>
It	O
is	O
a	O
toolkit	O
for	O
developing	O
"	O
GUI-like	O
"	O
application	B-Application
software	I-Application
that	O
runs	O
under	O
a	O
terminal	B-Application
emulator	I-Application
.	O
</s>
<s>
It	O
also	O
optimizes	O
screen	O
changes	O
,	O
in	O
order	O
to	O
reduce	O
the	O
latency	O
experienced	O
when	O
using	O
remote	O
shells	B-Application
.	O
</s>
<s>
ncurses	B-Language
is	O
a	O
free-software	B-Application
emulation	O
of	O
the	O
System	B-Operating_System
V	I-Operating_System
Release	I-Operating_System
4.0	I-Operating_System
(	O
SVr4	O
)	O
curses	B-Device
.	O
</s>
<s>
There	O
are	O
bindings	O
for	O
ncurses	B-Language
in	O
a	O
variety	O
of	O
programming	O
languages	O
,	O
including	O
Ada	B-Language
,	O
Python	B-Language
,	O
Gambas	B-Language
,	O
Ruby	B-Language
,	O
PHP	B-Application
,	O
JavaScript	B-Language
,	O
and	O
Perl	B-Language
.	O
</s>
<s>
As	O
the	O
new	O
version	O
,	O
ncurses	B-Language
is	O
a	O
free-software	B-Application
emulation	O
of	O
the	O
System	B-Operating_System
V	I-Operating_System
Release	I-Operating_System
4.0	I-Operating_System
(	O
SVr4	O
)	O
curses	B-Device
,	O
which	O
was	O
itself	O
an	O
enhancement	O
over	O
the	O
discontinued	O
4.4	O
BSD	B-Operating_System
curses	B-Device
.	O
</s>
<s>
The	O
XSI	O
Curses	B-Device
standard	O
issued	O
by	O
X/Open	O
is	O
explicitly	O
and	O
closely	O
modeled	O
on	O
System	B-Operating_System
V	I-Operating_System
.	O
</s>
<s>
The	O
first	O
curses	B-Device
library	O
was	O
developed	O
at	O
the	O
University	O
of	O
California	O
at	O
Berkeley	O
,	O
for	O
a	O
BSD	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
,	O
around	O
1980	O
to	O
support	O
Rogue	B-Application
,	O
a	O
text-based	B-Application
adventure	O
game	O
.	O
</s>
<s>
It	O
originally	O
used	O
the	O
termcap	B-Application
library	O
,	O
which	O
was	O
used	O
in	O
other	O
programs	O
,	O
such	O
as	O
the	O
vi	B-Application
editor	I-Application
.	O
</s>
<s>
The	O
success	O
of	O
the	O
BSD	B-Operating_System
curses	B-Device
library	O
prompted	O
Bell	O
Labs	O
to	O
release	O
an	O
enhanced	O
curses	B-Device
library	O
in	O
their	O
System	B-Operating_System
V	I-Operating_System
Release	O
2	O
Unix	B-Application
systems	I-Application
.	O
</s>
<s>
This	O
library	O
was	O
more	O
powerful	O
and	O
instead	O
of	O
using	O
termcap	B-Application
,	O
it	O
used	O
terminfo	B-Device
.	O
</s>
<s>
However	O
,	O
due	O
to	O
AT&T	O
policy	O
regarding	O
source-code	O
distribution	O
,	O
this	O
improved	O
curses	B-Device
library	O
did	O
not	O
have	O
much	O
acceptance	O
in	O
the	O
BSD	B-Operating_System
community	O
.	O
</s>
<s>
Around	O
1982	O
,	O
Pavel	O
Curtis	O
started	O
work	O
on	O
a	O
freeware	B-License
clone	O
of	O
the	O
Bell	O
Labs	O
curses	B-Device
,	O
named	O
pcurses	O
,	O
which	O
was	O
maintained	O
by	O
various	O
people	O
through	O
1986	O
.	O
</s>
<s>
The	O
new	O
library	O
was	O
released	O
as	O
ncurses	B-Language
in	O
November	O
1993	O
,	O
with	O
version	O
1.8.1	O
as	O
the	O
first	O
major	O
release	O
.	O
</s>
<s>
Most	O
ncurses	B-Language
calls	O
can	O
be	O
easily	O
ported	O
to	O
the	O
old	O
curses	B-Device
.	O
</s>
<s>
System	B-Operating_System
V	I-Operating_System
curses	B-Device
implementations	O
can	O
support	O
BSD	B-Operating_System
curses	B-Device
programs	O
with	O
just	O
a	O
recompilation	B-Language
.	O
</s>
<s>
However	O
,	O
a	O
few	O
areas	O
are	O
problematic	O
,	O
such	O
as	O
handling	O
terminal	O
resizing	O
,	O
since	O
no	O
counterpart	O
exists	O
in	O
the	O
old	O
curses	B-Device
.	O
</s>
<s>
ncurses	B-Language
can	O
use	O
either	O
terminfo	B-Device
(	O
with	O
extensible	O
data	O
)	O
or	O
termcap	B-Application
.	O
</s>
<s>
Other	O
implementations	O
of	O
curses	B-Device
generally	O
use	O
terminfo	B-Device
;	O
a	O
minority	O
use	O
termcap	B-Application
.	O
</s>
<s>
ncurses	B-Language
is	O
a	O
part	O
of	O
the	B-Application
GNU	I-Application
Project	I-Application
,	O
but	O
is	O
not	O
distributed	O
under	O
the	O
GNU	B-License
GPL	I-License
or	O
LGPL	B-Application
.	O
</s>
<s>
Instead	O
,	O
it	O
is	O
distributed	O
under	O
a	O
permissive	B-License
free	I-License
software	I-License
licence	I-License
,	O
i.e.	O
,	O
the	B-License
MIT	I-License
License	I-License
.	O
</s>
<s>
This	O
is	O
due	O
to	O
the	O
agreement	O
made	O
with	O
the	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
at	O
the	O
time	O
the	O
developers	O
assigned	O
their	O
copyright	O
.	O
</s>
<s>
According	O
to	O
the	O
maintainer	O
Thomas	O
E	O
.	O
Dickey	O
,	O
this	O
precludes	O
relicensing	O
to	O
the	O
GPL	B-License
in	O
any	O
version	O
,	O
since	O
it	O
would	O
place	O
restrictions	O
on	O
the	O
programs	O
that	O
will	O
be	O
able	O
to	O
link	O
to	O
the	O
libraries	O
.	O
</s>
<s>
There	O
are	O
hundreds	O
of	O
programs	O
which	O
use	O
ncurses	B-Language
.	O
</s>
<s>
Some	O
,	O
such	O
as	O
GNU	B-Application
Screen	I-Application
and	O
w3m	B-Application
,	O
use	O
only	O
the	O
termcap	B-Application
interface	O
and	O
perform	O
screen	O
management	O
themselves	O
.	O
</s>
<s>
Others	O
,	O
such	O
as	O
GNU	B-Protocol
Midnight	I-Protocol
Commander	I-Protocol
and	O
YaST	B-Device
,	O
use	O
the	O
curses	B-Device
programming	B-Application
interface	I-Application
.	O
</s>
