@@ -79,7 +68,7 @@
intattr_on(attr_tattrs,void*opts);intwattr_on(WINDOW*win,attr_tattrs,void*opts);
- intattroff(intattrs);
+ intattroff(intattrs);intwattroff(WINDOW*win,intattrs);intattron(intattrs);intwattron(WINDOW*win,intattrs);
@@ -91,11 +80,11 @@
intn,attr_tattr,shortpair,constvoid*opts);intmvchgat(inty,intx,intn,attr_tattr,shortpair,constvoid*opts);
- intmvwchgat(WINDOW*win,inty,intx,
- intn,attr_tattr,shortpair,constvoid*opts);
+ intmvwchgat(WINDOW*win,inty,intx,
+ intn,attr_tattr,shortpair,constvoid*opts);intcolor_set(shortpair,void*opts);
- intwcolor_set(WINDOW*win,shortpair,void*opts);
+ intwcolor_set(WINDOW*win,shortpair,void*opts);intstandend(void);intwstandend(WINDOW*win);
@@ -107,97 +96,118 @@
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
- character, and move with the character through any scrolling and in-
- sert/delete line/character operations. To the extent possible, they
+ character, and move with the character through any scrolling and
+ insert/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-
- tributes used for erasing and clearing.
+ of the window. See curs_bkgd(3x) for functions which modify the
+ attributes 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.
-
-
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:
+ wattr_set and wattr_get.
- o functions for manipulating only the window attributes (not color):
+ 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
+ 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 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
+ Use attr_on and wattr_on to turn on window attributes, i.e., values
+ OR'd together in attr, without affecting other attributes. Use
+ attr_off and wattr_off to turn off window attributes, again values OR'd
together in attr, without affecting other attributes.
-
- Most of the window attribute routines are extensions of older routines
- which assume that color pairs are OR'd into the attribute parameter.
- These older routines use the same name, omitting an underscore (_).
+
+ 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.
+
+ 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
+ attributes (such as bold, reverse), as well as a few bits for color.
+ Those bits correspond to the A_COLOR symbol. The COLOR_PAIR macro
+ provides a value which can be OR'd into the attribute parameter. For
+ example, 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);
+
+ However, if the value does not fit, then the COLOR_PAIR macro uses only
+ the bits that fit. For example, because in ncursesA_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 same:
- 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.
+ int value = A_BOLD | COLOR_PAIR(input);
+ int output = PAIR_NUMBER(value);
- The remaining attr* functions operate exactly like the corresponding
- attr_* functions, except that they take arguments of type int rather
+ 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:
+ compatibility.
+
+ 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
- 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-
- sor move before acting.
+
+ The routine chgat changes the attributes of a given number of
+ characters 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
+ attributes all the way to the end of the current line. The wchgat
+ function generalizes this to any window; the mvwchgat function does a
+ cursor move before acting.
- In these functions, the color pair argument is a color-pair index (as
+ 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-
- ter.
+ foreground/background combination described by the color pair
+ parameter.
- 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
+ X/Open Curses does not mark these "restricted", because
o they have well established legacy use, and
- o there is no ambiguity about the way the attributes might be com-
- bined with a color pair.
+ o there is no ambiguity about the way the attributes might be
+ combined 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
+ 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_STANDOUT Best highlighting mode of the terminal
A_UNDERLINE Underlining
A_REVERSE Reverse video
A_BLINK Blinking
@@ -208,12 +218,17 @@
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)
+
+ You can thus use A_CHARTEXT to extract the character from a chtype,
+ A_ATTRIBUTES to obtain its rendering attributes, and A_COLOR to find
+ the color pair it uses.
- These video attributes are supported by attr_on and related functions
+ These video attributes are supported by attr_on and related functions
(which also support the attributes recognized by attron, etc.):
- NameDescription
- -----------------------------------------
+ NameDescription
+ -----------------------------------------------------------------
WA_HORIZONTAL Horizontal highlight
WA_LEFT Left highlight
WA_LOW Low highlight
@@ -221,12 +236,31 @@
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
+ 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.
+
+ All routines return the integer OK on success, or ERR on failure.
+
+ X/Open Curses does not specify any error conditions.
+
+ This implementation
+
+ o returns an error if the window pointer is null.
+
+ o returns an error if the color pair parameter for wcolor_set is
+ outside 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.
+
+ Functions prefixed with "mv" first perform cursor movement and fail if
+ the position (y, x) is outside the window boundaries.
+
+
These functions may be macros:
@@ -235,69 +269,68 @@
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
- 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
+ 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.
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_at-
- tribute_mode may also reset italics.
+ have the enter_italics_mode (sitm) and exit_italics_mode (ritm)
+ capabilities. Italics are not mentioned in X/Open Curses. Unlike the
+ other video attributes, A_ITALIC is unrelated to the set_attributes
+ capabilities. This implementation makes the assumption that
+ exit_attribute_mode may also reset italics.
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-
- tion uses that parameter in ABI 6 for the functions which have a color-
- pair parameter to support extendedcolorpairs:
+ X/Open Curses still (after more than twenty years) documents as
+ reserved for future use, saying that it should be NULL. This
+ implementation uses that parameter in ABI 6 for the functions which
+ have a color 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 and wattr_on,
+ 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.
+ color pair as an int value, in addition to retrieving it via the
+ standard 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.
+ o For functions which turn attributes off, e.g., wattr_off, the opts
+ parameter is ignored except except to check that it is 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
- not supported under SVr4.
+ These functions are described in X/Open Curses, 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 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".
- Under this implementation as well as SVr4 curses, these functions cor-
- rectly manipulate all other highlights (specifically, A_ALTCHARSET,
+ X/Open Curses 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".
+ Under this implementation as well as SVr4 curses, these functions
+ correctly manipulate all other highlights (specifically, A_ALTCHARSET,
A_PROTECT, and A_INVIS).
- XSI Curses added these entry points:
+ X/Open 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,
+ wattr_get, wattr_set
- The new functions are intended to work with a new series of highlight
+ The new functions are intended to work with a new series of highlight
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_STANDOUT Best highlighting mode of the terminal
WA_UNDERLINE Underlining
WA_REVERSE Reverse video
WA_BLINK Blinking
@@ -305,43 +338,169 @@
WA_BOLD Extra bright or bold
WA_ALTCHARSET Alternate character set
- The XSI curses standard specifies that each pair of corresponding A_
- and WA_-using functions operates on the same current-highlight informa-
- tion.
+ X/Open 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 X/Open Curses 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
+ values.
+
+ For example, the Solaris xpg4 (X/Open) curses declares attr_t to be
+ an unsigned short integer (16-bits), while chtype is a unsigned
+ integer (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 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).
+ o Because ncurses's attr_t can hold a color pair (in the A_COLOR
+ field), a call to wattr_on, wattr_off, or wattr_set may alter the
+ window's color. If the color pair information in the attribute
+ parameter is zero, no change is made to the window's color.
+ This is consistent with SVr4 curses; X/Open Curses does not specify
+ this.
-
- All routines return the integer OK on success, or ERR on failure.
+ The X/Open Curses extended conformance level adds new highlights
+ A_HORIZONTAL, 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).
- X/Open does not define any error conditions.
- This implementation
+
+ X/Open Curses is largely based on SVr4 curses, adding support for
+ "wide-characters" (not specific to Unicode). Some of the X/Open
+ differences from SVr4 curses address the way video attributes can be
+ applied 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.
- o returns an error if the window pointer is null.
+ 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
+ bold and/or reverse video). The BSD curses library provided functions
+ standout and standend which were carried along into X/Open Curses due
+ to their pervasive use in legacy applications.
- o returns an error if the color pair parameter for wcolor_set is out-
- side the range 0..COLOR_PAIRS-1.
+ Some terminals in the 1980s could support a variety of video
+ attributes, although the BSD curses library could do nothing with
+ those. 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.
- o does not return an error if either of the parameters of wattr_get
- used for retrieving attribute or color-pair values is NULL.
+ Goodheart's book UNIXCursesExplained (1991) describes SVr3 (1987),
+ commenting on several 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,
- 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
- the window pointer is null.
+ 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
+ V.3.2,
+
+ 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_
+ 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
+ integer sizes (32-bit versus 64-bit).
+
+ 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
+ alternate character set implementation. A 32-bit library can be used
+ on a 64-bit system, but not necessarily the reverse.
+
+ Bits
+ YearSystemArchColorCharNotes
+ ------------------------------------------------------------------------
+ 1992 Solaris 5.2 32 6 17 SVr4 curses
+ 1992 HP-UX 9 32 no 8 SVr2 curses
+ 1992 AIX 3.2 32 no 23 SVr2 curses
+ 1994 OSF/1 r3 32 no 23 SVr2 curses
+ 1995 HP-UX 10.00 32 6 16 SVr3 curses_colr
+ 1995 HP-UX 10.00 32 6 8 SVr4, X/Open curses
+ 1995 Solaris 5.4 32/64 7 16 X/Open curses
+ 1996 AIX 4.2 32 7 16 X/Open curses
+ 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
+
+ Notes:
+
+ Regarding HP-UX,
+
+ 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
+ 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
+ interface is not customized for 32-bit and 64-bit versions.
+
+ o Unlike other systems which evolved from AT&T code, OSF/1
+ provided a new implementation for X/Open curses.
+
+ Regarding Solaris,
+
+ o The initial release of Solaris was in 1992.
+
+ 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
+ introduced in 1997, but did not modify the SVr4 curses
+ interface.
+
+ Regarding U/Win,
+
+ o Development of the curses library began in 1991, stopped in
+ 2000.
+
+ o Color support was added in 1998.
+
+ 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
+ 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(1). 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.