These routines manipulate the current attributes of the named window,
which then apply to all characters that are written into the window
- with waddch, waddstr and wprintw. Attributes are a property of the
+ with waddch, waddstr and wprintw. Attributes are a property of the
character, and move with the character through any scrolling and in-
sert/delete line/character operations. To the extent possible, they
are displayed as appropriate modifications to the graphic rendition of
characters put on the screen.
These routines do not affect the attributes used when erasing portions
- of the window. See curs_bkgd(3X) for functions which modify the at-
+ of the window. See curs_bkgd(3x) for functions which modify the at-
tributes used for erasing and clearing.
- Routines which do not have a WINDOW* parameter apply to stdscr. For
- example, attr_set is the stdscr variant of wattr_set.
+ Routines which do not have a WINDOW* parameter apply to stdscr. For
+ example, attr_set is the stdscr variant of wattr_set.
There are two sets of functions:
- o functions for manipulating the window attributes and color: wat-
- tr_set and wattr_get.
+ o functions for manipulating the window attributes and color: wat-
+ tr_set and wattr_get.
- o functions for manipulating only the window attributes (not color):
- wattr_on and wattr_off.
+ o functions for manipulating only the window attributes (not color):
+ wattr_on and wattr_off.
- The wattr_set function sets the current attributes of the given window
- to attrs, with color specified by pair.
+ The wattr_set function sets the current attributes of the given window
+ to attrs, with color specified by pair.
- Use wattr_get to retrieve attributes for the given window.
+ Use wattr_get to retrieve attributes for the given window.
- Use attr_on and wattr_on to turn on window attributes, i.e., values
- OR'd together in attr, without affecting other attributes. Use at-
- tr_off and wattr_off to turn off window attributes, again values OR'd
- together in attr, without affecting other attributes.
+ Use attr_on and wattr_on to turn on window attributes, i.e., values
+ OR'd together in attr, without affecting other attributes. Use at-
+ tr_off and wattr_off to turn off window attributes, again values OR'd
+ together in attr, without affecting other attributes.
- The X/Open window attribute routines which set or get, turn on or off
+ The X/Open window attribute routines which set or get, turn on or off
are extensions of older routines which assume that color pairs are OR'd
into the attribute parameter. These newer routines use similar names,
- because X/Open simply added an underscore (_) for the newer names.
+ because X/Open simply added an underscore (_) for the newer names.
- The int datatype used in the legacy routines is treated as if it is the
- same size as chtype (used by addch(3X)). It holds the common video at-
+ The int datatype used in the legacy routines is treated as if it is the
+ same size as chtype (used by addch(3x)). It holds the common video at-
tributes (such as bold, reverse), as well as a few bits for color.
- Those bits correspond to the A_COLOR symbol. The COLOR_PAIR macro pro-
+ Those bits correspond to the A_COLOR symbol. The COLOR_PAIR macro pro-
vides a value which can be OR'd into the attribute parameter. For ex-
- ample, as long as that value fits into the A_COLOR mask, then these
+ ample, as long as that value fits into the A_COLOR mask, then these
calls produce similar results:
- attrset(A_BOLD | COLOR_PAIR(pair));
- attr_set(A_BOLD, pair, NULL);
+ attrset(A_BOLD | COLOR_PAIR(pair));
+ attr_set(A_BOLD, pair, NULL);
- However, if the value does not fit, then the COLOR_PAIR macro uses only
- the bits that fit. For example, because in ncurses A_COLOR has eight
- (8) bits, then COLOR_PAIR(259) is 4 (i.e., 259 is 4 more than the limit
+ However, if the value does not fit, then the COLOR_PAIR macro uses only
+ the bits that fit. For example, because in ncurses A_COLOR has eight
+ (8) bits, then COLOR_PAIR(259) is 4 (i.e., 259 is 4 more than the limit
255).
- The PAIR_NUMBER macro extracts a pair number from an int (or chtype).
- For example, the input and output values in these statements would be
+ The PAIR_NUMBER macro extracts a pair number from an int (or chtype).
+ For example, the input and output values in these statements would be
the same:
- int value = A_BOLD | COLOR_PAIR(input);
- int output = PAIR_NUMBER(value);
+ int value = A_BOLD | COLOR_PAIR(input);
+ int output = PAIR_NUMBER(value);
- The attrset routine is a legacy feature predating SVr4 curses but kept
+ The attrset routine is a legacy feature predating SVr4 curses but kept
in X/Open Curses for the same reason that SVr4 curses kept it: compati-
bility.
- The remaining attr* functions operate exactly like the corresponding
- attr_* functions, except that they take arguments of type int rather
- than attr_t.
+ The remaining attr* functions operate exactly like the corresponding
+ attr_* functions, except that they take arguments of type int rather
+ than attr_t.
- There is no corresponding attrget function as such in X/Open Curses,
- although ncurses provides getattrs (see curs_legacy(3X)).
+ There is no corresponding attrget function as such in X/Open Curses,
+ although ncurses provides getattrs (see curs_legacy(3x)).
- The routine chgat changes the attributes of a given number of charac-
- ters starting at the current cursor location of stdscr. It does not
+ The routine chgat changes the attributes of a given number of charac-
+ ters starting at the current cursor location of stdscr. It does not
update the cursor and does not perform wrapping. A character count of
-1 or greater than the remaining window width means to change at-
- tributes all the way to the end of the current line. The wchgat func-
- tion generalizes this to any window; the mvwchgat function does a cur-
+ tributes all the way to the end of the current line. The wchgat func-
+ tion generalizes this to any window; the mvwchgat function does a cur-
sor move before acting.
- In these functions, the color pair argument is a color-pair index (as
- in the first argument of init_pair, see curs_color(3X)).
+ In these functions, the color pair argument is a color-pair index (as
+ in the first argument of init_pair, see curs_color(3x)).
- The routine color_set sets the current color of the given window to the
- foreground/background combination described by the color pair parame-
+ The routine color_set sets the current color of the given window to the
+ foreground/background combination described by the color pair parame-
ter.
- The routine standout is the same as attron(A_STANDOUT). The routine
- standend is the same as attrset(A_NORMAL) or attrset(0), that is, it
+ The routine standout is the same as attron(A_STANDOUT). The routine
+ standend is the same as attrset(A_NORMAL) or attrset(0), that is, it
turns off all attributes.
X/Open does not mark these "restricted", because
- o they have well established legacy use, and
+ o they have well established legacy use, and
- o there is no ambiguity about the way the attributes might be com-
+ o there is no ambiguity about the way the attributes might be com-
bined with a color pair.
- The following video attributes, defined in <curses.h>, can be passed to
- the routines attron, attroff, and attrset, or OR'd with the characters
- passed to addch (see curs_addch(3X)).
+ The following video attributes, defined in <curses.h>, can be passed to
+ the routines attron, attroff, and attrset, or OR'd with the characters
+ passed to addch (see curs_addch(3x)).
- NameDescription
+ NameDescription
-----------------------------------------------------------------
- A_NORMAL Normal display (no highlight)
- A_STANDOUT Best highlighting mode of the terminal.
- A_UNDERLINE Underlining
- A_REVERSE Reverse video
- A_BLINK Blinking
- A_DIM Half bright
- A_BOLD Extra bright or bold
- A_PROTECT Protected mode
- A_INVIS Invisible or blank mode
- A_ALTCHARSET Alternate character set
- A_ITALIC Italics (non-X/Open extension)
- A_CHARTEXT Bit-mask to extract a character
- A_COLOR Bit-mask to extract a color (legacy routines)
-
- These video attributes are supported by attr_on and related functions
- (which also support the attributes recognized by attron, etc.):
-
- NameDescription
+ A_NORMAL Normal display (no highlight)
+ A_STANDOUT Best highlighting mode of the terminal.
+ A_UNDERLINE Underlining
+ A_REVERSE Reverse video
+ A_BLINK Blinking
+ A_DIM Half bright
+ A_BOLD Extra bright or bold
+ A_PROTECT Protected mode
+ A_INVIS Invisible or blank mode
+ A_ALTCHARSET Alternate character set
+ A_ITALIC Italics (non-X/Open extension)
+ A_CHARTEXT Bit-mask to extract a character
+ A_COLOR Bit-mask to extract a color (legacy routines)
+
+ These video attributes are supported by attr_on and related functions
+ (which also support the attributes recognized by attron, etc.):
+
+ NameDescription
-----------------------------------------
- WA_HORIZONTAL Horizontal highlight
- WA_LEFT Left highlight
- WA_LOW Low highlight
- WA_RIGHT Right highlight
- WA_TOP Top highlight
- WA_VERTICAL Vertical highlight
+ WA_HORIZONTAL Horizontal highlight
+ WA_LEFT Left highlight
+ WA_LOW Low highlight
+ WA_RIGHT Right highlight
+ WA_TOP Top highlight
+ WA_VERTICAL Vertical highlight
The return values of many of these routines are not meaningful (they
are implemented as macro-expanded assignments and simply return their
argument). The SVr4 manual page claims (falsely) that these routines
- always return 1.
+ always return 1.
These functions may be macros:
- attroff, wattroff, attron, wattron, attrset, wattrset, standend
- and standout.
+ attroff, wattroff, attron, wattron, attrset, wattrset, standend
+ and standout.
Color pair values can only be OR'd with attributes if the pair number
- is less than 256. The alternate functions such as color_set can pass a
+ is less than 256. The alternate functions such as color_set can pass a
color pair value directly. However, ncurses ABI 4 and 5 simply OR this
value within the alternate functions. You must use ncurses ABI 6 to
support more than 256 color pairs.
@@ -279,54 +279,54 @@
X/Open Curses is largely based on SVr4 curses, adding support for
"wide-characters" (not specific to Unicode). Some of the X/Open dif-
ferences from SVr4 curses address the way video attributes can be ap-
- plied to wide-characters. But aside from that, attrset and attr_set
+ plied to wide-characters. But aside from that, attrset and attr_set
are similar. SVr4 curses provided the basic features for manipulating
video attributes. However, earlier versions of curses provided a part
of these features.
As seen in 2.8BSD, curses assumed 7-bit characters, using the eighth
- bit of a byte to represent the standout feature (often implemented as
+ bit of a byte to represent the standout feature (often implemented as
bold and/or reverse video). The BSD curses library provided functions
- standout and standend which were carried along into X/Open Curses due
+ standout and standend which were carried along into X/Open Curses due
to their pervasive use in legacy applications.
Some terminals in the 1980s could support a variety of video at-
tributes, although the BSD curses library could do nothing with those.
- System V (1983) provided an improved curses library. It defined the A_
+ System V (1983) provided an improved curses library. It defined the A_
symbols for use by applications to manipulate the other attributes.
There are few useful references for the chronology.
- Goodheart's book UNIXCursesExplained (1991) describes SVr3 (1987),
+ Goodheart's book UNIXCursesExplained (1991) describes SVr3 (1987),
commenting on several functions:
- o the attron, attroff, attrset functions (and most of the functions
+ o the attron, attroff, attrset functions (and most of the functions
found in SVr4 but not in BSD curses) were introduced by System V,
- o the alternate character set feature with A_ALTCHARSET was added in
- SVr2 and improved in SVr3 (by adding acs_map[]),
+ o the alternate character set feature with A_ALTCHARSET was added in
+ SVr2 and improved in SVr3 (by adding acs_map[]),
- ostart_color and related color-functions were introduced by System
+ ostart_color and related color-functions were introduced by System
V.3.2,
- o pads, soft-keys were added in SVr3, and
+ o pads, soft-keys were added in SVr3, and
- Goodheart did not mention the background character or the cchar_t type.
- Those are respectively SVr4 and X/Open features. He did mention the A_
+ Goodheart did not mention the background character or the cchar_t type.
+ Those are respectively SVr4 and X/Open features. He did mention the A_
constants, but did not indicate their values. Those were not the same
in different systems, even for those marked as System V.
Different Unix systems used different sizes for the bit-fields in
- chtype for characters and colors, and took into account the different
+ chtype for characters and colors, and took into account the different
integer sizes (32-bit versus 64-bit).
- This table showing the number of bits for A_COLOR and A_CHARTEXT was
+ This table showing the number of bits for A_COLOR and A_CHARTEXT was
gleaned from the curses header files for various operating systems and
architectures. The inferred architecture and notes reflect the format
and size of the defined constants as well as clues such as the alter-
nate character set implementation. A 32-bit library can be used on a
64-bit system, but not necessarily the reverse.
- YearSystemArchColorCharNotes
+ YearSystemArchColorCharNotes
----------------------------------------------------------------
1992 Solaris 5.2 32 6 17 SVr4 curses
1992 HPUX 9 32 no 8 SVr2 curses
@@ -339,181 +339,181 @@
1996 OSF/1 r4 32 6 16 X/Open curses
1997 HP-UX 11.00 32 6 8 X/Open curses
- 2000 U/Win 32/64 7/31 16 uses chtype
+ 2000 U/Win 32/64 7/31 16 uses chtype
Notes:
Regarding HP-UX,
- o HP-UX 10.20 (1996) added support for 64-bit PA-RISC processors
+ o HP-UX 10.20 (1996) added support for 64-bit PA-RISC processors
in 1996.
- o HP-UX 10.30 (1997) marked "curses_colr" obsolete. That version
+ o HP-UX 10.30 (1997) marked "curses_colr" obsolete. That version
of curses was dropped with HP-UX 11.30 in 2006.
Regarding OSF/1 (and Tru64),
- o These used 64-bit hardware. Like ncurses, the OSF/1 curses in-
+ o These used 64-bit hardware. Like ncurses, the OSF/1 curses in-
terface is not customized for 32-bit and 64-bit versions.
- o Unlike other systems which evolved from AT&T code, OSF/1 provid-
+ o Unlike other systems which evolved from AT&T code, OSF/1 provid-
ed a new implementation for X/Open curses.
Regarding Solaris,
- o The initial release of Solaris was in 1992.
+ o The initial release of Solaris was in 1992.
- o The xpg4 (X/Open) curses was developed by MKS from 1990 to 1995.
+ o The xpg4 (X/Open) curses was developed by MKS from 1990 to 1995.
Sun's copyright began in 1996.
- o Sun updated the X/Open curses interface after 64-bit support was
+ o Sun updated the X/Open curses interface after 64-bit support was
introduced in 1997, but did not modify the SVr4 curses inter-
face.
Regarding U/Win,
- o Development of the curses library began in 1991, stopped in
+ o Development of the curses library began in 1991, stopped in
2000.
- o Color support was added in 1998.
+ o Color support was added in 1998.
- o The library uses only chtype (no cchar_t).
+ o The library uses only chtype (no cchar_t).
Once X/Open curses was adopted in the mid-1990s, the constraint of a
- 32-bit interface with many colors and wide-characters for chtype became
- a moot point. The cchar_t structure (whose size and members are not
+ 32-bit interface with many colors and wide-characters for chtype became
+ a moot point. The cchar_t structure (whose size and members are not
specified in X/Open Curses) could be extended as needed.
Other interfaces are rarely used now:
- o BSD curses was improved slightly in 1993/1994 using Keith Bostic's
- modification to make the library 8-bit clean for nvi. He moved
- standout attribute to a structure member.
+ o BSD curses was improved slightly in 1993/1994 using Keith Bostic's
+ modification to make the library 8-bit clean for nvi. He moved
+ standout attribute to a structure member.
The resulting 4.4BSD curses was replaced by ncurses over the next
ten years.
- o U/Win is rarely used now.
+ o U/Win is rarely used now.
- This implementation provides the A_ITALIC attribute for terminals which
- have the enter_italics_mode (sitm) and exit_italics_mode (ritm) capa-
+ This implementation provides the A_ITALIC attribute for terminals which
+ have the enter_italics_mode (sitm) and exit_italics_mode (ritm) capa-
bilities. Italics are not mentioned in X/Open Curses. Unlike the oth-
- er video attributes, A_ITALIC is unrelated to the set_attributes capa-
- bilities. This implementation makes the assumption that exit_attri-
- bute_mode may also reset italics.
+ er video attributes, A_ITALIC is unrelated to the set_attributes capa-
+ bilities. This implementation makes the assumption that exit_attri-
+ bute_mode may also reset italics.
- Each of the functions added by XSI Curses has a parameter opts, which
+ Each of the functions added by XSI Curses has a parameter opts, which
X/Open Curses still (after more than twenty years) documents as re-
- served for future use, saying that it should be NULL. This implementa-
+ served for future use, saying that it should be NULL. This implementa-
tion uses that parameter in ABI 6 for the functions which have a color-
- pair parameter to support extendedcolorpairs:
+ pair parameter to support extendedcolorpairs:
- o For functions which modify the color, e.g., wattr_set, if opts is
- set it is treated as a pointer to int, and used to set the color
- pair instead of the shortpair parameter.
+ o For functions which modify the color, e.g., wattr_set, if opts is
+ set it is treated as a pointer to int, and used to set the color
+ pair instead of the shortpair parameter.
- o For functions which retrieve the color, e.g., wattr_get, if opts is
- set it is treated as a pointer to int, and used to retrieve the
- color pair as an int value, in addition retrieving it via the stan-
- dard pointer to short parameter.
+ o For functions which retrieve the color, e.g., wattr_get, if opts is
+ set it is treated as a pointer to int, and used to retrieve the
+ color pair as an int value, in addition retrieving it via the stan-
+ dard pointer to short parameter.
- The remaining functions which have opts, but do not manipulate color,
- e.g., wattr_on and wattr_off are not used by this implementation except
- to check that they are NULL.
+ The remaining functions which have opts, but do not manipulate color,
+ e.g., wattr_on and wattr_off are not used by this implementation except
+ to check that they are NULL.
These functions are supported in the XSI Curses standard, Issue 4. The
- standard defined the dedicated type for highlights, attr_t, which was
- not defined in SVr4 curses. The functions taking attr_t arguments were
+ standard defined the dedicated type for highlights, attr_t, which was
+ not defined in SVr4 curses. The functions taking attr_t arguments were
not supported under SVr4.
Very old versions of this library did not force an update of the screen
- when changing the attributes. Use touchwin to force the screen to
+ when changing the attributes. Use touchwin to force the screen to
match the updated attributes.
The XSI Curses standard states that whether the traditional functions
- attron/attroff/attrset can manipulate attributes other than A_BLINK,
- A_BOLD, A_DIM, A_REVERSE, A_STANDOUT, or A_UNDERLINE is "unspecified".
+ attron/attroff/attrset can manipulate attributes other than A_BLINK,
+ A_BOLD, A_DIM, A_REVERSE, A_STANDOUT, or A_UNDERLINE is "unspecified".
Under this implementation as well as SVr4 curses, these functions cor-
- rectly manipulate all other highlights (specifically, A_ALTCHARSET,
- A_PROTECT, and A_INVIS).
+ rectly manipulate all other highlights (specifically, A_ALTCHARSET,
+ A_PROTECT, and A_INVIS).
XSI Curses added these entry points:
- attr_get, attr_on, attr_off, attr_set, wattr_on, wattr_off, wat-
- tr_get, wattr_set
+ attr_get, attr_on, attr_off, attr_set, wattr_on, wattr_off, wat-
+ tr_get, wattr_set
The new functions are intended to work with a new series of highlight
- macros prefixed with WA_. The older macros have direct counterparts in
+ macros prefixed with WA_. The older macros have direct counterparts in
the newer set of names:
- NameDescription
+ NameDescription
------------------------------------------------------------
- WA_NORMAL Normal display (no highlight)
- WA_STANDOUT Best highlighting mode of the terminal.
- WA_UNDERLINE Underlining
- WA_REVERSE Reverse video
- WA_BLINK Blinking
- WA_DIM Half bright
- WA_BOLD Extra bright or bold
- WA_ALTCHARSET Alternate character set
+ WA_NORMAL Normal display (no highlight)
+ WA_STANDOUT Best highlighting mode of the terminal.
+ WA_UNDERLINE Underlining
+ WA_REVERSE Reverse video
+ WA_BLINK Blinking
+ WA_DIM Half bright
+ WA_BOLD Extra bright or bold
+ WA_ALTCHARSET Alternate character set
XSI curses does not assign values to these symbols, nor does it state
whether or not they are related to the similarly-named A_NORMAL, etc.:
- o The XSI curses standard specifies that each pair of corresponding
- A_ and WA_-using functions operates on the same current-highlight
+ o The XSI curses standard specifies that each pair of corresponding
+ A_ and WA_-using functions operates on the same current-highlight
information.
- o However, in some implementations, those symbols have unrelated val-
+ o However, in some implementations, those symbols have unrelated val-
ues.
- For example, the Solaris xpg4 (X/Open) curses declares attr_t to be
- an unsigned short integer (16-bits), while chtype is a unsigned in-
- teger (32-bits). The WA_ symbols in this case are different from
- the A_ symbols because they are used for a smaller datatype which
- does not represent A_CHARTEXT or A_COLOR.
+ For example, the Solaris xpg4 (X/Open) curses declares attr_t to be
+ an unsigned short integer (16-bits), while chtype is a unsigned in-
+ teger (32-bits). The WA_ symbols in this case are different from
+ the A_ symbols because they are used for a smaller datatype which
+ does not represent A_CHARTEXT or A_COLOR.
In this implementation (as in many others), the values happen to be
- the same because it simplifies copying information between chtype
- and cchar_t variables.
+ the same because it simplifies copying information between chtype
+ and cchar_t variables.
- The XSI standard extended conformance level adds new highlights A_HORI-
- ZONTAL, A_LEFT, A_LOW, A_RIGHT, A_TOP, A_VERTICAL (and corresponding
- WA_ macros for each). As of August 2013, no known terminal provides
- these highlights (i.e., via the sgr1 capability).
+ The XSI standard extended conformance level adds new highlights A_HORI-
+ ZONTAL, A_LEFT, A_LOW, A_RIGHT, A_TOP, A_VERTICAL (and corresponding
+ WA_ macros for each). As of August 2013, no known terminal provides
+ these highlights (i.e., via the sgr1 capability).
- All routines return the integer OK on success, or ERR on failure.
+ All routines return the integer OK on success, or ERR on failure.
X/Open does not define any error conditions.
This implementation
- o returns an error if the window pointer is null.
+ o returns an error if the window pointer is null.
- o returns an error if the color pair parameter for wcolor_set is out-
+ o returns an error if the color pair parameter for wcolor_set is out-
side the range 0..COLOR_PAIRS-1.
- o does not return an error if either of the parameters of wattr_get
- used for retrieving attribute or color-pair values is NULL.
+ o does not return an error if either of the parameters of wattr_get
+ used for retrieving attribute or color-pair values is NULL.
Functions with a "mv" prefix first perform a cursor movement using
- wmove, and return an error if the position is outside the window, or if
+ wmove, and return an error if the position is outside the window, or if
the window pointer is null.