The ncurses library routines give the user a terminal-
independent method of updating character screens with rea-
- sonable optimization. This implementation is ``new
- curses'' (ncurses) and is the approved replacement for
- 4.4BSD classic curses, which has been discontinued. This
- describes ncurses version 5.9 (patch 20110404).
+ sonable optimization. This implementation is "new curses"
+ (ncurses) and is the approved replacement for 4.4BSD clas-
+ sic curses, which has been discontinued. This describes
+ ncurses version 6.0 (patch 20170218).
The ncurses library emulates the curses library of System
V Release 4 UNIX, and XPG4 (X/Open Portability Guide)
@@ -96,41 +93,42 @@
lation; use of soft label keys; terminfo capabilities; and
access to low-level terminal-manipulation routines.
+
+
The library uses the locale which the calling program has
initialized. That is normally done with setlocale:
- setlocale(LC_ALL,"");
-
- If the locale is not initialized, the library assumes that
- characters are printable as in ISO-8859-1, to work with
- certain legacy programs. You should initialize the locale
- and not rely on specific details of the library when the
- locale has not been setup.
+ setlocale(LC_ALL,"");
+ If the locale is not initialized, the library assumes that
+ characters are printable as in ISO-8859-1, to work with cer-
+ tain legacy programs. You should initialize the locale and
+ not rely on specific details of the library when the locale
+ has not been setup.
The function initscr or newterm must be called to initial-
ize the library before any of the other routines that deal
- with windows and screens are used. The routine endwin
+ with windows and screens are used. The routine endwin(3x)
must be called before exiting.
To get character-at-a-time input without echoing (most
interactive, screen oriented programs want this), the fol-
lowing sequence should be used:
- initscr();cbreak();noecho();
-
- Most programs would additionally use the sequence:
+ initscr();cbreak();noecho();
+ Most programs would additionally use the sequence:
nonl();intrflush(stdscr,FALSE);keypad(stdscr,TRUE);
+ Before a curses program is run, the tab stops of the terminal
+ should be set and its initialization strings, if defined, must
+ be output. This can be done by executing the tputinit com-
+ mand after the shell environment variable TERM has been
+ exported. tset(1) is usually responsible for doing this.
+ [See terminfo(5) for further details.]
- Before a curses program is run, the tab stops of the ter-
- minal should be set and its initialization strings, if
- defined, must be output. This can be done by executing
- the tputinit command after the shell environment variable
- TERM has been exported. tset(1) is usually responsible
- for doing this. [See terminfo(5) for further details.]
+
The ncurses library permits manipulation of data struc-
tures, called windows, which can be thought of as two-
dimensional arrays of characters representing all or part
@@ -150,59 +148,57 @@
Among those, the most basic routines are move and addch.
More general versions of these routines are included with
names beginning with w, allowing the user to specify a
- window. The routines not beginning with w affect stdscr.
+ window. The routines not beginning with w affect stdscr.
- After using routines to manipulate a window, refresh is
- called, telling curses to make the user's CRT screen look
- like stdscr. The characters in a window are actually of
- type chtype, (character and attribute data) so that other
- information about the character may also be stored with
- each character.
+ After using routines to manipulate a window, refresh(3x)
+ is called, telling curses to make the user's CRT screen
+ look like stdscr. The characters in a window are actually
+ of type chtype, (character and attribute data) so that
+ other information about the character may also be stored
+ with each character.
- Special windows called pads may also be manipulated.
+ Special windows called pads may also be manipulated.
These are windows which are not constrained to the size of
- the screen and whose contents need not be completely dis-
+ the screen and whose contents need not be completely dis-
played. See curs_pad(3x) for more information.
- In addition to drawing characters on the screen, video
- attributes and colors may be supported, causing the char-
- acters to show up in such modes as underlined, in reverse
- video, or in color on terminals that support such display
+ In addition to drawing characters on the screen, video
+ attributes and colors may be supported, causing the char-
+ acters to show up in such modes as underlined, in reverse
+ video, or in color on terminals that support such display
enhancements. Line drawing characters may be specified to
- be output. On input, curses is also able to translate
- arrow and function keys that transmit escape sequences
- into single values. The video attributes, line drawing
- characters, and input values use names, defined in
+ be output. On input, curses is also able to translate
+ arrow and function keys that transmit escape sequences
+ into single values. The video attributes, line drawing
+ characters, and input values use names, defined in
<curses.h>, such as A_REVERSE, ACS_HLINE, and KEY_LEFT.
+
+
If the environment variables LINES and COLUMNS are set, or
- if the program is executing in a window environment, line
- and column information in the environment will override
+ if the program is executing in a window environment, line
+ and column information in the environment will override
information read by terminfo. This would affect a program
- running in an AT&T 630 layer, for example, where the size
+ running in an AT&T 630 layer, for example, where the size
of a screen is changeable (see ENVIRONMENT).
- If the environment variable TERMINFO is defined, any pro-
- gram using curses checks for a local terminal definition
- before checking in the standard place. For example, if
+ If the environment variable TERMINFO is defined, any pro-
+ gram using curses checks for a local terminal definition
+ before checking in the standard place. For example, if
TERM is set to att4424, then the compiled terminal defini-
tion is found in
- /usr/share/terminfo/a/att4424.
-
- (The a is copied from the first letter of att4424 to avoid
- creation of huge directories.) However, if TERMINFO is
- set to $HOME/myterms, curses first checks
+ /usr/share/terminfo/a/att4424.
+ (The a is copied from the first letter of att4424 to avoid
+ creation of huge directories.) However, if TERMINFO is set
+ to $HOME/myterms, curses first checks
$HOME/myterms/a/att4424,
+ and if that fails, it then checks
- and if that fails, it then checks
-
- /usr/share/terminfo/a/att4424.
-
- This is useful for developing experimental definitions or
- when write permission in /usr/share/terminfo is not avail-
- able.
+ /usr/share/terminfo/a/att4424.
+ This is useful for developing experimental definitions or when
+ write permission in /usr/share/terminfo is not available.
The integer variables LINES and COLS are defined in
<curses.h> and will be filled in by initscr with the size
@@ -214,7 +210,8 @@
clearing and redrawing a screen containing garbage. The
curscr can be used in only a few routines.
- RoutineandArgumentNames
+
+
Many curses routines have two or more versions. The rou-
tines prefixed with w require a window argument. The rou-
tines prefixed with p require a pad argument. Those with-
@@ -246,71 +243,66 @@
any configuration of the library. There are two common
configurations of the library:
- ncurses
- the "normal" library, which handles 8-bit
- characters. The normal (8-bit) library stores
- characters combined with attributes in chtype
- data.
-
- Attributes alone (no corresponding character)
- may be stored in chtype or the equivalent
- attr_t data. In either case, the data is
- stored in something like an integer.
-
- Each cell (row and column) in a WINDOW is
- stored as a chtype.
-
- ncursesw
- the so-called "wide" library, which handles
- multibyte characters (see the section on
- ALTERNATECONFIGURATIONS). The "wide" library
- includes all of the calls from the "normal"
- library. It adds about one third more calls
- using data types which store multibyte charac-
- ters:
-
- cchar_t
- corresponds to chtype. However it is a
- structure, because more data is stored
- than can fit into an integer. The char-
- acters are large enough to require a full
- integer value - and there may be more
- than one character per cell. The video
- attributes and color are stored in sepa-
- rate fields of the structure.
-
- Each cell (row and column) in a WINDOW is
- stored as a cchar_t.
-
- wchar_t
- stores a "wide" character. Like chtype,
- this may be an integer.
-
- wint_t
- stores a wchar_t or WEOF - not the same,
- though both may have the same size.
-
- The "wide" library provides new functions
- which are analogous to functions in the "nor-
- mal" library. There is a naming convention
- which relates many of the normal/wide vari-
- ants: a "_w" is inserted into the name. For
- example, waddch becomes wadd_wch.
-
-
- RoutineNameIndex
+ ncurses
+ the "normal" library, which handles 8-bit charac-
+ ters. The normal (8-bit) library stores charac-
+ ters combined with attributes in chtype data.
+
+ Attributes alone (no corresponding character) may
+ be stored in chtype or the equivalent attr_t data.
+ In either case, the data is stored in something
+ like an integer.
+
+ Each cell (row and column) in a WINDOW is stored
+ as a chtype.
+
+ ncursesw
+ the so-called "wide" library, which handles multi-
+ byte characters (see the section on ALTERNATECON-
+ FIGURATIONS). The "wide" library includes all of
+ the calls from the "normal" library. It adds
+ about one third more calls using data types which
+ store multibyte characters:
+
+ cchar_t
+ corresponds to chtype. However it is a
+ structure, because more data is stored than
+ can fit into an integer. The characters are
+ large enough to require a full integer value
+ - and there may be more than one character
+ per cell. The video attributes and color are
+ stored in separate fields of the structure.
+
+ Each cell (row and column) in a WINDOW is
+ stored as a cchar_t.
+
+ wchar_t
+ stores a "wide" character. Like chtype, this
+ may be an integer.
+
+ wint_t
+ stores a wchar_t or WEOF - not the same,
+ though both may have the same size.
+
+ The "wide" library provides new functions which
+ are analogous to functions in the "normal"
+ library. There is a naming convention which
+ relates many of the normal/wide variants: a "_w"
+ is inserted into the name. For example, waddch
+ becomes wadd_wch.
+
+
+
- Routines that return an integer return ERR upon failure
- and an integer value other than ERR upon successful com-
- pletion, unless otherwise noted in the routine descrip-
+
+ Routines that return an integer return ERR upon failure
+ and an integer value other than ERR upon successful com-
+ pletion, unless otherwise noted in the routine descrip-
tions.
+ As a general rule, routines check for null pointers passed
+ as parameters, and handle this as an error.
+
All macros return the value of the w version, except
setscrreg, wsetscrreg, getyx, getbegyx, and getmaxyx. The
return values of setscrreg, wsetscrreg, getyx, getbegyx,
@@ -766,347 +769,473 @@
Routines that return pointers return NULL on error.
-
The following environment symbols are useful for customiz-
ing the runtime behavior of the ncurses library. The most
important ones have been already discussed in detail.
- BAUDRATE
- The debugging library checks this environment symbol
- when the application has redirected output to a file.
- The symbol's numeric value is used for the baudrate.
- If no value is found, ncurses uses 9600. This allows
- testers to construct repeatable test-cases that take
- into account costs that depend on baudrate.
-
- CC When set, change occurrences of the command_character
- (i.e., the cmdch capability) of the loaded terminfo
- entries to the value of this symbol. Very few ter-
- minfo entries provide this feature.
-
- Because this name is also used in development envi-
- ronments to represent the C compiler's name, ncurses
- ignores it if it does not happen to be a single char-
- acter.
-
- COLUMNS
- Specify the width of the screen in characters.
- Applications running in a windowing environment usu-
- ally are able to obtain the width of the window in
- which they are executing. If neither the COLUMNS
- value nor the terminal's screen size is available,
- ncurses uses the size which may be specified in the
- terminfo database (i.e., the cols capability).
-
- It is important that your application use a correct
- size for the screen. This is not always possible
- because your application may be running on a host
- which does not honor NAWS (Negotiations About Window
- Size), or because you are temporarily running as
- another user. However, setting COLUMNS and/or LINES
- overrides the library's use of the screen size
- obtained from the operating system.
-
- Either COLUMNS or LINES symbols may be specified
- independently. This is mainly useful to circumvent
- legacy misfeatures of terminal descriptions, e.g.,
- xterm which commonly specifies a 65 line screen. For
- best results, lines and cols should not be specified
- in a terminal description for terminals which are run
- as emulations.
-
- Use the use_env function to disable all use of exter-
- nal environment (including system calls) to determine
- the screen size.
-
- ESCDELAY
- Specifies the total time, in milliseconds, for which
- ncurses will await a character sequence, e.g., a
- function key. The default value, 1000 milliseconds,
- is enough for most uses. However, it is made a vari-
- able to accommodate unusual applications.
-
- The most common instance where you may wish to change
- this value is to work with slow hosts, e.g., running
- on a network. If the host cannot read characters
- rapidly enough, it will have the same effect as if
- the terminal did not send characters rapidly enough.
- The library will still see a timeout.
-
- Note that xterm mouse events are built up from char-
- acter sequences received from the xterm. If your
- application makes heavy use of multiple-clicking, you
- may wish to lengthen this default value because the
- timeout applies to the composed multi-click event as
- well as the individual clicks.
-
- In addition to the environment variable, this imple-
- mentation provides a global variable with the same
- name. Portable applications should not rely upon the
- presence of ESCDELAY in either form, but setting the
- environment variable rather than the global variable
- does not create problems when compiling an applica-
- tion.
-
- HOME Tells ncurses where your home directory is. That is
- where it may read and write auxiliary terminal
- descriptions:
-
- $HOME/.termcap
- $HOME/.terminfo
-
- LINES
- Like COLUMNS, specify the height of the screen in
- characters. See COLUMNS for a detailed description.
-
- MOUSE_BUTTONS_123
- This applies only to the OS/2 EMX port. It specifies
- the order of buttons on the mouse. OS/2 numbers a
- 3-button mouse inconsistently from other platforms:
-
- 1 = left
- 2 = right
- 3 = middle.
-
- This symbol lets you customize the mouse. The symbol
- must be three numeric digits 1-3 in any order, e.g.,
- 123 or 321. If it is not specified, ncurses uses
- 132.
-
- NCURSES_ASSUMED_COLORS
- Override the compiled-in assumption that the termi-
- nal's default colors are white-on-black (see
- default_colors(3x)). You may set the foreground and
- background color values with this environment vari-
- able by proving a 2-element list: foreground,back-
- ground. For example, to tell ncurses to not assume
- anything about the colors, set this to "-1,-1". To
- make it green-on-black, set it to "2,0". Any posi-
- tive value from zero to the terminfo max_colors value
- is allowed.
-
- NCURSES_GPM_TERMS
- This applies only to ncurses configured to use the
- GPM interface.
-
- If present, the environment variable is a list of one
- or more terminal names against which the TERM envi-
- ronment variable is matched. Setting it to an empty
- value disables the GPM interface; using the built-in
- support for xterm, etc.
-
- If the environment variable is absent, ncurses will
- attempt to open GPM if TERM contains "linux".
-
- NCURSES_NO_HARD_TABS
- Ncurses may use tabs as part of the cursor movement
- optimization. In some cases, your terminal driver
- may not handle these properly. Set this environment
- variable to disable the feature. You can also adjust
- your stty settings to avoid the problem.
-
- NCURSES_NO_MAGIC_COOKIES
- Some terminals use a magic-cookie feature which
- requires special handling to make highlighting and
- other video attributes display properly. You can
- suppress the highlighting entirely for these termi-
- nals by setting this environment variable.
-
- NCURSES_NO_PADDING
- Most of the terminal descriptions in the terminfo
- database are written for real "hardware" terminals.
- Many people use terminal emulators which run in a
- windowing environment and use curses-based applica-
- tions. Terminal emulators can duplicate all of the
- important aspects of a hardware terminal, but they do
- not have the same limitations. The chief limitation
- of a hardware terminal from the standpoint of your
- application is the management of dataflow, i.e., tim-
- ing. Unless a hardware terminal is interfaced into a
- terminal concentrator (which does flow control), it
- (or your application) must manage dataflow, prevent-
- ing overruns. The cheapest solution (no hardware
- cost) is for your program to do this by pausing after
- operations that the terminal does slowly, such as
- clearing the display.
-
- As a result, many terminal descriptions (including
- the vt100) have delay times embedded. You may wish
- to use these descriptions, but not want to pay the
- performance penalty.
-
- Set the NCURSES_NO_PADDING symbol to disable all but
- mandatory padding. Mandatory padding is used as a
- part of special control sequences such as flash.
-
- NCURSES_NO_SETBUF
- Normally ncurses enables buffered output during ter-
- minal initialization. This is done (as in SVr4
- curses) for performance reasons. For testing pur-
- poses, both of ncurses and certain applications, this
- feature is made optional. Setting the
- NCURSES_NO_SETBUF variable disables output buffering,
- leaving the output in the original (usually line
- buffered) mode.
-
- NCURSES_NO_UTF8_ACS
- During initialization, the ncurses library checks for
- special cases where VT100 line-drawing (and the cor-
- responding alternate character set capabilities)
- described in the terminfo are known to be missing.
- Specifically, when running in a UTF-8 locale, the
- Linux console emulator and the GNU screen program
- ignore these. Ncurses checks the TERM environment
- variable for these. For other special cases, you
- should set this environment variable. Doing this
- tells ncurses to use Unicode values which correspond
- to the VT100 line-drawing glyphs. That works for the
- special cases cited, and is likely to work for termi-
- nal emulators.
-
- When setting this variable, you should set it to a
- nonzero value. Setting it to zero (or to a nonnum-
- ber) disables the special check for "linux" and
- "screen".
-
- As an alternative to the environment variable,
- ncurses checks for an extended terminfo capability
- U8. This is a numeric capability which can be com-
- piled using tic-x. For example
-
- # linux console, if patched to provide working
- # VT100 shift-in/shift-out, with corresponding font.
- linux-vt100|linux console with VT100 line-graphics,
- U8#0, use=linux,
-
- # uxterm with vt100Graphics resource set to false
- xterm-utf8|xterm relying on UTF-8 line-graphics,
- U8#1, use=xterm,
-
- The name "U8" is chosen to be two characters, to per-
- mit it to be used by applications that use ncurses'
- termcap interface.
-
- NCURSES_TRACE
- During initialization, the ncurses debugging library
- checks the NCURSES_TRACE symbol. If it is defined,
- to a numeric value, ncurses calls the trace function,
- using that value as the argument.
-
- The argument values, which are defined in curses.h,
- provide several types of information. When running
- with traces enabled, your application will write the
- file trace to the current directory.
-
- TERM Denotes your terminal type. Each terminal type is
- distinct, though many are similar.
-
- TERMCAP
- If the ncurses library has been configured with term-
- cap support, ncurses will check for a terminal's
- description in termcap form if it is not available in
- the terminfo database.
-
- The TERMCAP symbol contains either a terminal
- description (with newlines stripped out), or a file
- name telling where the information denoted by the
- TERM symbol exists. In either case, setting it
- directs ncurses to ignore the usual place for this
- information, e.g., /etc/termcap.
-
- TERMINFO
- Overrides the directory in which ncurses searches for
- your terminal description. This is the simplest, but
- not the only way to change the list of directories.
- The complete list of directories in order follows:
-
- o the last directory to which ncurses wrote, if
- any, is searched first
-
- o the directory specified by the TERMINFO symbol
-
- o $HOME/.terminfo
-
- o directories listed in the TERMINFO_DIRS symbol
-
- o one or more directories whose names are config-
- ured and compiled into the ncurses library, e.g.,
- /usr/share/terminfo
-
- TERMINFO_DIRS
- Specifies a list of directories to search for termi-
- nal descriptions. The list is separated by colons
- (i.e., ":") on Unix, semicolons on OS/2 EMX. All of
- the terminal descriptions are in terminfo form, which
- makes a subdirectory named for the first letter of
- the terminal names therein.
-
- TERMPATH
- If TERMCAP does not hold a file name then ncurses
- checks the TERMPATH symbol. This is a list of file-
- names separated by spaces or colons (i.e., ":") on
- Unix, semicolons on OS/2 EMX. If the TERMPATH symbol
- is not set, ncurses looks in the files /etc/termcap,
- /usr/share/misc/termcap and $HOME/.termcap, in that
- order.
+ CC
+ When set, change occurrences of the command_character
+ (i.e., the cmdch capability) of the loaded terminfo
+ entries to the value of this variable. Very few terminfo
+ entries provide this feature.
+
+ Because this name is also used in development environments
+ to represent the C compiler's name, ncurses ignores it if
+ it does not happen to be a single character.
+
+
+
+ The debugging library checks this environment variable
+ when the application has redirected output to a file. The
+ variable's numeric value is used for the baudrate. If no
+ value is found, ncurses uses 9600. This allows testers to
+ construct repeatable test-cases that take into account
+ costs that depend on baudrate.
+
+
+
+ Specify the width of the screen in characters. Applica-
+ tions running in a windowing environment usually are able
+ to obtain the width of the window in which they are exe-
+ cuting. If neither the COLUMNS value nor the terminal's
+ screen size is available, ncurses uses the size which may
+ be specified in the terminfo database (i.e., the cols
+ capability).
+
+ It is important that your application use a correct size
+ for the screen. This is not always possible because your
+ application may be running on a host which does not honor
+ NAWS (Negotiations About Window Size), or because you are
+ temporarily running as another user. However, setting
+ COLUMNS and/or LINES overrides the library's use of the
+ screen size obtained from the operating system.
+
+ Either COLUMNS or LINES symbols may be specified indepen-
+ dently. This is mainly useful to circumvent legacy mis-
+ features of terminal descriptions, e.g., xterm which com-
+ monly specifies a 65 line screen. For best results, lines
+ and cols should not be specified in a terminal description
+ for terminals which are run as emulations.
+
+ Use the use_env function to disable all use of external
+ environment (but not including system calls) to determine
+ the screen size. Use the use_tioctl function to update
+ COLUMNS or LINES to match the screen size obtained from
+ system calls or the terminal database.
+
+
+
+ Specifies the total time, in milliseconds, for which
+ ncurses will await a character sequence, e.g., a function
+ key. The default value, 1000 milliseconds, is enough for
+ most uses. However, it is made a variable to accommodate
+ unusual applications.
+
+ The most common instance where you may wish to change this
+ value is to work with slow hosts, e.g., running on a net-
+ work. If the host cannot read characters rapidly enough,
+ it will have the same effect as if the terminal did not
+ send characters rapidly enough. The library will still
+ see a timeout.
+
+ Note that xterm mouse events are built up from character
+ sequences received from the xterm. If your application
+ makes heavy use of multiple-clicking, you may wish to
+ lengthen this default value because the timeout applies to
+ the composed multi-click event as well as the individual
+ clicks.
+
+ In addition to the environment variable, this implementa-
+ tion provides a global variable with the same name. Por-
+ table applications should not rely upon the presence of
+ ESCDELAY in either form, but setting the environment vari-
+ able rather than the global variable does not create prob-
+ lems when compiling an application.
+
+
+
+ Tells ncurses where your home directory is. That is where
+ it may read and write auxiliary terminal descriptions:
+
+ $HOME/.termcap
+ $HOME/.terminfo
+
+
+
+ This applies only to the OS/2 EMX port. It specifies the
+ order of buttons on the mouse. OS/2 numbers a 3-button
+ mouse inconsistently from other platforms:
+
+ 1 = left
+ 2 = right
+ 3 = middle.
+
+ This variable lets you customize the mouse. The variable
+ must be three numeric digits 1-3 in any order, e.g., 123
+ or 321. If it is not specified, ncurses uses 132.
+
+
+
+ Override the compiled-in assumption that the terminal's
+ default colors are white-on-black (see default_col-
+ ors(3x)). You may set the foreground and background color
+ values with this environment variable by proving a 2-ele-
+ ment list: foreground,background. For example, to tell
+ ncurses to not assume anything about the colors, set this
+ to "-1,-1". To make it green-on-black, set it to "2,0".
+ Any positive value from zero to the terminfo max_colors
+ value is allowed.
+
+
+
+ This applies only to the MinGW port of ncurses.
+
+ The Console2 program's handling of the Microsoft Console
+ API call CreateConsoleScreenBuffer is defective. Applica-
+ tions which use this will hang. However, it is possible
+ to simulate the action of this call by mapping coordi-
+ nates, explicitly saving and restoring the original screen
+ contents. Setting the environment variable NCGDB has the
+ same effect.
+
+
+
+ This applies only to ncurses configured to use the GPM
+ interface.
+
+ If present, the environment variable is a list of one or
+ more terminal names against which the TERM environment
+ variable is matched. Setting it to an empty value dis-
+ ables the GPM interface; using the built-in support for
+ xterm, etc.
+
+ If the environment variable is absent, ncurses will
+ attempt to open GPM if TERM contains "linux".
+
+
+
+ Ncurses may use tabs as part of the cursor movement opti-
+ mization. In some cases, your terminal driver may not
+ handle these properly. Set this environment variable to
+ disable the feature. You can also adjust your stty set-
+ tings to avoid the problem. NCURSES_NO_MAGIC_COOKIE Some
+ terminals use a magic-cookie feature which requires spe-
+ cial handling to make highlighting and other video
+ attributes display properly. You can suppress the high-
+ lighting entirely for these terminals by setting this
+ environment variable.
+
+
+
+ Most of the terminal descriptions in the terminfo database
+ are written for real "hardware" terminals. Many people
+ use terminal emulators which run in a windowing environ-
+ ment and use curses-based applications. Terminal emula-
+ tors can duplicate all of the important aspects of a hard-
+ ware terminal, but they do not have the same limitations.
+ The chief limitation of a hardware terminal from the
+ standpoint of your application is the management of
+ dataflow, i.e., timing. Unless a hardware terminal is
+ interfaced into a terminal concentrator (which does flow
+ control), it (or your application) must manage dataflow,
+ preventing overruns. The cheapest solution (no hardware
+ cost) is for your program to do this by pausing after
+ operations that the terminal does slowly, such as clearing
+ the display.
+
+ As a result, many terminal descriptions (including the
+ vt100) have delay times embedded. You may wish to use
+ these descriptions, but not want to pay the performance
+ penalty.
+
+ Set the NCURSES_NO_PADDING environment variable to disable
+ all but mandatory padding. Mandatory padding is used as a
+ part of special control sequences such as flash.
+
+
+
+ This setting is obsolete. Before changes
+
+ o started with 5.9 patch 20120825 and
+
+ o continued though 5.9 patch 20130126
+
+ ncurses enabled buffered output during terminal initial-
+ ization. This was done (as in SVr4 curses) for perfor-
+ mance reasons. For testing purposes, both of ncurses and
+ certain applications, this feature was made optional.
+ Setting the NCURSES_NO_SETBUF variable disabled output
+ buffering, leaving the output in the original (usually
+ line buffered) mode.
+
+ In the current implementation, ncurses performs its own
+ buffering and does not require this workaround. It does
+ not modify the buffering of the standard output.
+
+ The reason for the change was to make the behavior for
+ interrupts and other signals more robust. One drawback is
+ that certain nonconventional programs would mix ordinary
+ stdio calls with ncurses calls and (usually) work. This
+ is no longer possible since ncurses is not using the
+ buffered standard output but its own output (to the same
+ file descriptor). As a special case, the low-level calls
+ such as putp still use the standard output. But high-
+ level curses calls do not.
+
+
+
+ During initialization, the ncurses library checks for spe-
+ cial cases where VT100 line-drawing (and the corresponding
+ alternate character set capabilities) described in the
+ terminfo are known to be missing. Specifically, when run-
+ ning in a UTF-8 locale, the Linux console emulator and the
+ GNU screen program ignore these. Ncurses checks the TERM
+ environment variable for these. For other special cases,
+ you should set this environment variable. Doing this
+ tells ncurses to use Unicode values which correspond to
+ the VT100 line-drawing glyphs. That works for the special
+ cases cited, and is likely to work for terminal emulators.
+
+ When setting this variable, you should set it to a nonzero
+ value. Setting it to zero (or to a nonnumber) disables
+ the special check for "linux" and "screen".
+
+ As an alternative to the environment variable, ncurses
+ checks for an extended terminfo capability U8. This is a
+ numeric capability which can be compiled using tic-x.
+ For example
+
+ # linux console, if patched to provide working
+ # VT100 shift-in/shift-out, with corresponding font.
+ linux-vt100|linux console with VT100 line-graphics,
+ U8#0, use=linux,
+
+ # uxterm with vt100Graphics resource set to false
+ xterm-utf8|xterm relying on UTF-8 line-graphics,
+ U8#1, use=xterm,
+
+ The name "U8" is chosen to be two characters, to permit it
+ to be used by applications that use ncurses' termcap
+ interface.
+
+
+
+ During initialization, the ncurses debugging library
+ checks the NCURSES_TRACE environment variable. If it is
+ defined, to a numeric value, ncurses calls the trace func-
+ tion, using that value as the argument.
+
+ The argument values, which are defined in curses.h, pro-
+ vide several types of information. When running with
+ traces enabled, your application will write the file trace
+ to the current directory.
+
+ See curs_trace(3x) for more information.
+
+
+
+ Denotes your terminal type. Each terminal type is dis-
+ tinct, though many are similar.
+
+ TERM is commonly set by terminal emulators to help appli-
+ cations find a workable terminal description. Some of
+ those choose a popular approximation, e.g., "ansi",
+ "vt100", "xterm" rather than an exact fit. Not infre-
+ quently, your application will have problems with that
+ approach, e.g., incorrect function-key definitions.
+
+ If you set TERM in your environment, it has no effect on
+ the operation of the terminal emulator. It only affects
+ the way applications work within the terminal. Likewise,
+ as a general rule (xterm being a rare exception), terminal
+ emulators which allow you to specify TERM as a parameter
+ or configuration value do not change their behavior to
+ match that setting.
+
+
+
+ If the ncurses library has been configured with termcap
+ support, ncurses will check for a terminal's description
+ in termcap form if it is not available in the terminfo
+ database.
+
+ The TERMCAP environment variable contains either a termi-
+ nal description (with newlines stripped out), or a file
+ name telling where the information denoted by the TERM
+ environment variable exists. In either case, setting it
+ directs ncurses to ignore the usual place for this infor-
+ mation, e.g., /etc/termcap.
+
+
+
+ ncurses can be configured to read from multiple terminal
+ databases. The TERMINFO variable overrides the location
+ for the default terminal database. Terminal descriptions
+ (in terminal format) are stored in terminal databases:
+
+ o Normally these are stored in a directory tree, using
+ subdirectories named by the first letter of the termi-
+ nal names therein.
+
+ This is the scheme used in System V, which legacy Unix
+ systems use, and the TERMINFO variable is used by
+ curses applications on those systems to override the
+ default location of the terminal database.
+
+ o If ncurses is built to use hashed databases, then each
+ entry in this list may be the path of a hashed data-
+ base file, e.g.,
+
+ /usr/share/terminfo.db
+
+ rather than
+
+ /usr/share/terminfo/
+
+ The hashed database uses less disk-space and is a lit-
+ tle faster than the directory tree. However, some
+ applications assume the existence of the directory
+ tree, reading it directly rather than using the ter-
+ minfo library calls.
+
+ o If ncurses is built with a support for reading termcap
+ files directly, then an entry in this list may be the
+ path of a termcap file.
+
+ o If the TERMINFO variable begins with "hex:" or "b64:",
+ ncurses uses the remainder of that variable as a com-
+ piled terminal description. You might produce the
+ base64 format using infocmp(1m):
+
+ TERMINFO="$(infocmp -0 -Q2 -q)"
+ export TERMINFO
+
+ The compiled description is used if it corresponds to
+ the terminal identified by the TERM variable.
+
+ Setting TERMINFO is the simplest, but not the only way to
+ set location of the default terminal database. The com-
+ plete list of database locations in order follows:
+
+ o the last terminal database to which ncurses wrote,
+ if any, is searched first
+
+ o the location specified by the TERMINFO environment
+ variable
+
+ o $HOME/.terminfo
+
+ o locations listed in the TERMINFO_DIRS environment
+ variable
+
+ o one or more locations whose names are configured
+ and compiled into the ncurses library, i.e.,
+
+ o /usr/local/ncurses/share/ter-
+ minfo:/usr/share/terminfo (corresponding to the
+ TERMINFO_DIRS variable)
+
+ o /usr/share/terminfo (corresponding to the TER-
+ MINFO variable)
+
+
+
+ Specifies a list of locations to search for terminal
+ descriptions. Each location in the list is a terminal
+ database as described in the section on the TERMINFO vari-
+ able. The list is separated by colons (i.e., ":") on
+ Unix, semicolons on OS/2 EMX.
+
+ There is no corresponding feature in System V terminfo; it
+ is an extension developed for ncurses.
+
+
+
+ If TERMCAP does not hold a file name then ncurses checks
+ the TERMPATH environment variable. This is a list of
+ filenames separated by spaces or colons (i.e., ":") on
+ Unix, semicolons on OS/2 EMX.
+
+ If the TERMPATH environment variable is not set, ncurses
+ looks in the files
+
+ /etc/termcap, /usr/share/misc/termcap and $HOME/.termcap,
+
+ in that order.
The library may be configured to disregard the following
variables when the current user is the superuser (root),
- or if the application uses setuid or setgid permissions:
- $TERMINFO, $TERMINFO_DIRS, $TERMPATH, as well as $HOME.
+ or if the application uses setuid or setgid permissions:
+ $TERMINFO, $TERMINFO_DIRS, $TERMPATH, as well as $HOME.
-
-
ALTERNATE CONFIGURATIONS
- Several different configurations are possible, depending
- on the configure script options used when building
- ncurses. There are a few main options whose effects are
+
+
+ Several different configurations are possible, depending
+ on the configure script options used when building
+ ncurses. There are a few main options whose effects are
visible to the applications developer using ncurses:
--disable-overwrite
- The standard include for ncurses is as noted in SYN-
+ The standard include for ncurses is as noted in SYN-OPSIS:
- #include<curses.h>
+ #include<curses.h>
- This option is used to avoid filename conflicts when
- ncurses is not the main implementation of curses of
- the computer. If ncurses is installed disabling
- overwrite, it puts its headers in a subdirectory,
+ This option is used to avoid filename conflicts when
+ ncurses is not the main implementation of curses of
+ the computer. If ncurses is installed disabling
+ overwrite, it puts its headers in a subdirectory,
e.g.,
- #include<ncurses/curses.h>
+ #include<ncurses/curses.h>
- It also omits a symbolic link which would allow you
+ It also omits a symbolic link which would allow you
to use -lcurses to build executables.
--enable-widec
- The configure script renames the library and (if the
- --disable-overwrite option is used) puts the header
+ The configure script renames the library and (if the
+ --disable-overwrite option is used) puts the header
files in a different subdirectory. All of the
- library names have a "w" appended to them, i.e.,
+ library names have a "w" appended to them, i.e.,
instead of
- -lncurses
+ -lncurses
you link with
- -lncursesw
+ -lncursesw
You must also define _XOPEN_SOURCE_EXTENDED when com-
- piling for the wide-character library to use the
- extended (wide-character) functions. The curses.h
- file which is installed for the wide-character
- library is designed to be compatible with the normal
+ piling for the wide-character library to use the
+ extended (wide-character) functions. The curses.h
+ file which is installed for the wide-character
+ library is designed to be compatible with the normal
library's header. Only the size of the WINDOW struc-
- ture differs, and very few applications require more
- than a pointer to WINDOWs. If the headers are
- installed allowing overwrite, the wide-character
- library's headers should be installed last, to allow
- applications to be built using either library from
+ ture differs, and very few applications require more
+ than a pointer to WINDOWs. If the headers are
+ installed allowing overwrite, the wide-character
+ library's headers should be installed last, to allow
+ applications to be built using either library from
the same set of headers.
+ --with-pthread
+ The configure script renames the library. All of the
+ library names have a "t" appended to them (before any
+ "w" added by --enable-widec).
+
+ The global variables such as LINES are replaced by
+ macros to allow read-only access. At the same time,
+ setter-functions are provided to set these values.
+ Some applications (very few) may require changes to
+ work with this convention.
+
--with-shared
--with-normal
@@ -1114,86 +1243,91 @@
--with-debug
--with-profile
- The shared and normal (static) library names differ
- by their suffixes, e.g., libncurses.so and
- libncurses.a. The debug and profiling libraries add
- a "_g" and a "_p" to the root names respectively,
- e.g., libncurses_g.a and libncurses_p.a.
+ The shared and normal (static) library names differ
+ by their suffixes, e.g., libncurses.so and libn-
+ curses.a. The debug and profiling libraries add a
+ "_g" and a "_p" to the root names respectively, e.g.,
+ libncurses_g.a and libncurses_p.a.
--with-trace
- The trace function normally resides in the debug
+ The trace function normally resides in the debug
library, but it is sometimes useful to configure this
- in the shared library. Configure scripts should
+ in the shared library. Configure scripts should
check for the function's existence rather than assum-
ing it is always in the debug library.
-
The ncurses library can be compiled with an option
(-DUSE_GETCAP) that falls back to the old-style /etc/term-
cap file if the terminal setup code cannot find a terminfo
- entry corresponding to TERM. Use of this feature is not
- recommended, as it essentially includes an entire termcap
- compiler in the ncurses startup code, at significant cost
+ entry corresponding to TERM. Use of this feature is not
+ recommended, as it essentially includes an entire termcap
+ compiler in the ncurses startup code, at significant cost
in core and startup cycles.
- The ncurses library includes facilities for capturing
- mouse events on certain terminals (including xterm). See
+ The ncurses library includes facilities for capturing
+ mouse events on certain terminals (including xterm). See
the curs_mouse(3x) manual page for details.
- The ncurses library includes facilities for responding to
- window resizing events, e.g., when running in an xterm.
- See the resizeterm(3x) and wresize(3x) manual pages for
- details. In addition, the library may be configured with
+ The ncurses library includes facilities for responding to
+ window resizing events, e.g., when running in an xterm.
+ See the resizeterm(3x) and wresize(3x) manual pages for
+ details. In addition, the library may be configured with
a SIGWINCH handler.
- The ncurses library extends the fixed set of function key
- capabilities of terminals by allowing the application
- designer to define additional key sequences at runtime.
+ The ncurses library extends the fixed set of function key
+ capabilities of terminals by allowing the application
+ designer to define additional key sequences at runtime.
See the define_key(3x)key_defined(3x), and keyok(3x) man-
ual pages for details.
The ncurses library can exploit the capabilities of termi-
- nals which implement the ISO-6429 SGR 39 and SGR 49 con-
+ nals which implement the ISO-6429 SGR 39 and SGR 49 con-
trols, which allow an application to reset the terminal to
- its original foreground and background colors. From the
- users' perspective, the application is able to draw col-
- ored text on a background whose color is set indepen-
- dently, providing better control over color contrasts.
+ its original foreground and background colors. From the
+ users' perspective, the application is able to draw col-
+ ored text on a background whose color is set indepen-
+ dently, providing better control over color contrasts.
See the default_colors(3x) manual page for details.
- The ncurses library includes a function for directing
- application output to a printer attached to the terminal
+ The ncurses library includes a function for directing
+ application output to a printer attached to the terminal
device. See the curs_print(3x) manual page for details.
-
-
PORTABILITY
- The ncurses library is intended to be BASE-level confor-
+
+ The ncurses library is intended to be BASE-level confor-
mant with XSI Curses. The EXTENDED XSI Curses functional-
ity (including color support) is supported.
- A small number of local differences (that is, individual
- differences between the XSI Curses and ncurses calls) are
- described in PORTABILITY sections of the library man
+ A small number of local differences (that is, individual
+ differences between the XSI Curses and ncurses calls) are
+ described in PORTABILITY sections of the library man
pages.
+ Unlike other implementations, this one checks parameters
+ such as pointers to WINDOW structures to ensure they are
+ not null. The main reason for providing this behavior is
+ to guard against programmer error. The standard interface
+ does not provide a way for the library to tell an applica-
+ tion which of several possible errors were detected.
+ Relying on this (or some other) extension will adversely
+ affect the portability of curses applications.
+
This implementation also contains several extensions:
o The routine has_key is not part of XPG4, nor is it
@@ -1227,41 +1361,80 @@
o This implementation can also be configured to provide
a set of functions which improve the ability to manage
- multiple screens. See curs_sp_funcs(3x) for details.
+ multiple screens. See curs_sp_funcs(3x) for details.
- In historic curses versions, delays embedded in the capa-
+ In historic curses versions, delays embedded in the capa-
bilities cr, ind, cub1, ff and tab activated corresponding
- delay bits in the UNIX tty driver. In this implementa-
- tion, all padding is done by sending NUL bytes. This
- method is slightly more expensive, but narrows the inter-
- face to the UNIX kernel significantly and increases the
+ delay bits in the UNIX tty driver. In this implementa-
+ tion, all padding is done by sending NUL bytes. This
+ method is slightly more expensive, but narrows the inter-
+ face to the UNIX kernel significantly and increases the
package's portability correspondingly.
-
-
NOTES
- The header file <curses.h> automatically includes the
+
+ The header file <curses.h> automatically includes the
header files <stdio.h> and <unctrl.h>.
- If standard output from a ncurses program is re-directed
- to something which is not a tty, screen updates will be
+ If standard output from a ncurses program is re-directed
+ to something which is not a tty, screen updates will be
directed to standard error. This was an undocumented fea-
ture of AT&T System V Release 3 curses.
-
-
AUTHORS
- Zeyd M. Ben-Halim, Eric S. Raymond, Thomas E. Dickey.
+