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<H1 class="no-header">curs_attr 3x</H1>
<PRE>
<STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG> <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>
</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
<STRONG>attr_get</STRONG>, <STRONG>wattr_get</STRONG>, <STRONG>attr_set</STRONG>, <STRONG>wattr_set</STRONG>, <STRONG>attr_off</STRONG>, <STRONG>wattr_off</STRONG>, <STRONG>attr_on</STRONG>,
<STRONG>wattr_on</STRONG>, <STRONG>attroff</STRONG>, <STRONG>wattroff</STRONG>, <STRONG>attron</STRONG>, <STRONG>wattron</STRONG>, <STRONG>attrset</STRONG>, <STRONG>wattrset</STRONG>, <STRONG>chgat</STRONG>,
<STRONG>wchgat</STRONG>, <STRONG>mvchgat</STRONG>, <STRONG>mvwchgat</STRONG>, <STRONG>color_set</STRONG>, <STRONG>wcolor_set</STRONG>, <STRONG>standend</STRONG>, <STRONG>wstandend</STRONG>,
<STRONG>standout</STRONG>, <STRONG>wstandout</STRONG> - <STRONG>curses</STRONG> character and window attribute control
routines
</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
<STRONG>int</STRONG> <STRONG>attr_get(attr_t</STRONG> <STRONG>*</STRONG><EM>attrs</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <STRONG>*</STRONG><EM>pair</EM><STRONG>,</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>wattr_get(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>attr_t</STRONG> <STRONG>*</STRONG><EM>attrs</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <STRONG>*</STRONG><EM>pair</EM><STRONG>,</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>attr_set(attr_t</STRONG> <EM>attrs</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <EM>pair</EM><STRONG>,</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>wattr_set(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>attr_t</STRONG> <EM>attrs</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <EM>pair</EM><STRONG>,</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>attr_off(attr_t</STRONG> <EM>attrs</EM><STRONG>,</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>wattr_off(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>attr_t</STRONG> <EM>attrs</EM><STRONG>,</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>attr_on(attr_t</STRONG> <EM>attrs</EM><STRONG>,</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>wattr_on(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>attr_t</STRONG> <EM>attrs</EM><STRONG>,</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>attroff(int</STRONG> <EM>attrs);</EM>
<STRONG>int</STRONG> <STRONG>wattroff(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>attrs</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>attron(int</STRONG> <EM>attrs</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>wattron(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>attrs</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>attrset(int</STRONG> <EM>attrs</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>wattrset(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>attrs</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>chgat(int</STRONG> <EM>n</EM><STRONG>,</STRONG> <STRONG>attr_t</STRONG> <EM>attr</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <EM>pair</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>wchgat(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG>
<STRONG>int</STRONG> <EM>n</EM><STRONG>,</STRONG> <STRONG>attr_t</STRONG> <EM>attr</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <EM>pair</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>mvchgat(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG>
<STRONG>int</STRONG> <EM>n</EM><STRONG>,</STRONG> <STRONG>attr_t</STRONG> <EM>attr</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <EM>pair</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>mvwchgat(WINDOW</STRONG> <STRONG>*</STRONG><EM>win,</EM> <EM>int</EM> <EM>y,</EM> <EM>int</EM> <EM>x</EM><STRONG>,</STRONG>
<STRONG>int</STRONG> <EM>n,</EM> <STRONG>attr_t</STRONG> <EM>attr</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <EM>pair</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>color_set(short</STRONG> <EM>pair</EM><STRONG>,</STRONG> <STRONG>void*</STRONG> <EM>opts</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>wcolor_set(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <EM>pair</EM><STRONG>,</STRONG> <STRONG>void*</STRONG> <EM>opts);</EM>
<STRONG>int</STRONG> <STRONG>standend(void);</STRONG>
<STRONG>int</STRONG> <STRONG>wstandend(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>standout(void);</STRONG>
<STRONG>int</STRONG> <STRONG>wstandout(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG>
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
These routines manipulate the current attributes of the named window,
which then apply to all characters that are written into the window
with <STRONG>waddch</STRONG>, <STRONG>waddstr</STRONG> and <STRONG>wprintw</STRONG>. 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 <STRONG><A HREF="curs_bkgd.3x.html">curs_bkgd(3x)</A></STRONG> for functions which modify the at-
tributes used for erasing and clearing.
Routines which do not have a <STRONG>WINDOW*</STRONG> parameter apply to <STRONG>stdscr</STRONG>. For
example, <STRONG>attr_set</STRONG> is the <STRONG>stdscr</STRONG> variant of <STRONG>wattr_set</STRONG>.
</PRE><H3><a name="h3-Window-attributes">Window attributes</a></H3><PRE>
There are two sets of functions:
<STRONG>o</STRONG> functions for manipulating the window attributes and color: <STRONG>wat-</STRONG>
<STRONG>tr_set</STRONG> and <STRONG>wattr_get</STRONG>.
<STRONG>o</STRONG> functions for manipulating only the window attributes (not color):
<STRONG>wattr_on</STRONG> and <STRONG>wattr_off</STRONG>.
The <STRONG>wattr_set</STRONG> function sets the current attributes of the given window
to <EM>attrs</EM>, with color specified by <EM>pair</EM>.
Use <STRONG>wattr_get</STRONG> to retrieve attributes for the given window.
Use <STRONG>attr_on</STRONG> and <STRONG>wattr_on</STRONG> to turn on window attributes, i.e., values
OR'd together in <EM>attr</EM>, without affecting other attributes. Use <STRONG>at-</STRONG>
<STRONG>tr_off</STRONG> and <STRONG>wattr_off</STRONG> to turn off window attributes, again values OR'd
together in <EM>attr</EM>, without affecting other attributes.
</PRE><H3><a name="h3-Legacy-window-attributes">Legacy window attributes</a></H3><PRE>
The X/Open window attribute routines which <EM>set</EM> or <EM>get</EM>, turn <EM>on</EM> or <EM>off</EM>
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 (<STRONG>_</STRONG>) for the newer names.
The <STRONG>int</STRONG> datatype used in the legacy routines is treated as if it is the
same size as <STRONG>chtype</STRONG> (used by <STRONG><A HREF="curs_addch.3x.html">addch(3x)</A></STRONG>). It holds the common video at-
tributes (such as bold, reverse), as well as a few bits for color.
Those bits correspond to the <STRONG>A_COLOR</STRONG> symbol. The <STRONG>COLOR_PAIR</STRONG> 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 <STRONG>A_COLOR</STRONG> mask, then these
calls produce similar results:
attrset(A_BOLD | COLOR_PAIR(<EM>pair</EM>));
attr_set(A_BOLD, <EM>pair</EM>, NULL);
However, if the value does not fit, then the <STRONG>COLOR_PAIR</STRONG> macro uses only
the bits that fit. For example, because in ncurses <STRONG>A_COLOR</STRONG> has eight
(8) bits, then <STRONG>COLOR_PAIR(</STRONG><EM>259</EM><STRONG>)</STRONG> is 4 (i.e., 259 is 4 more than the limit
255).
The <STRONG>PAIR_NUMBER</STRONG> macro extracts a pair number from an <STRONG>int</STRONG> (or <STRONG>chtype</STRONG>).
For example, the <EM>input</EM> and <EM>output</EM> values in these statements would be
the same:
int value = A_BOLD | COLOR_PAIR(<EM>input</EM>);
int <EM>output</EM> = PAIR_NUMBER(value);
The <STRONG>attrset</STRONG> 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 <STRONG>attr</STRONG>* functions operate exactly like the corresponding
<STRONG>attr_</STRONG>* functions, except that they take arguments of type <STRONG>int</STRONG> rather
than <STRONG>attr_t</STRONG>.
There is no corresponding <STRONG>attrget</STRONG> function as such in X/Open Curses,
although ncurses provides <STRONG>getattrs</STRONG> (see <STRONG><A HREF="curs_legacy.3x.html">curs_legacy(3x)</A></STRONG>).
</PRE><H3><a name="h3-Change-character-rendition">Change character rendition</a></H3><PRE>
The routine <STRONG>chgat</STRONG> changes the attributes of a given number of charac-
ters starting at the current cursor location of <STRONG>stdscr</STRONG>. 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 <STRONG>wchgat</STRONG> func-
tion generalizes this to any window; the <STRONG>mvwchgat</STRONG> function does a cur-
sor move before acting.
In these functions, the color <EM>pair</EM> argument is a color-pair index (as
in the first argument of <STRONG>init_pair</STRONG>, see <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>).
</PRE><H3><a name="h3-Change-window-color">Change window color</a></H3><PRE>
The routine <STRONG>color_set</STRONG> sets the current color of the given window to the
foreground/background combination described by the color <EM>pair</EM> parame-
ter.
</PRE><H3><a name="h3-Standout">Standout</a></H3><PRE>
The routine <STRONG>standout</STRONG> is the same as <STRONG>attron(A_STANDOUT)</STRONG>. The routine
<STRONG>standend</STRONG> is the same as <STRONG>attrset(A_NORMAL)</STRONG> or <STRONG>attrset(0)</STRONG>, that is, it
turns off all attributes.
X/Open does not mark these "restricted", because
<STRONG>o</STRONG> they have well established legacy use, and
<STRONG>o</STRONG> there is no ambiguity about the way the attributes might be com-
bined with a color pair.
</PRE><H2><a name="h2-VIDEO-ATTRIBUTES">VIDEO ATTRIBUTES</a></H2><PRE>
The following video attributes, defined in <STRONG><curses.h></STRONG>, can be passed to
the routines <STRONG>attron</STRONG>, <STRONG>attroff</STRONG>, and <STRONG>attrset</STRONG>, or OR'd with the characters
passed to <STRONG>addch</STRONG> (see <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>).
<EM>Name</EM> <EM>Description</EM>
-----------------------------------------------------------------
<STRONG>A_NORMAL</STRONG> Normal display (no highlight)
<STRONG>A_STANDOUT</STRONG> Best highlighting mode of the terminal.
<STRONG>A_UNDERLINE</STRONG> Underlining
<STRONG>A_REVERSE</STRONG> Reverse video
<STRONG>A_BLINK</STRONG> Blinking
<STRONG>A_DIM</STRONG> Half bright
<STRONG>A_BOLD</STRONG> Extra bright or bold
<STRONG>A_PROTECT</STRONG> Protected mode
<STRONG>A_INVIS</STRONG> Invisible or blank mode
<STRONG>A_ALTCHARSET</STRONG> Alternate character set
<STRONG>A_ITALIC</STRONG> Italics (non-X/Open extension)
<STRONG>A_CHARTEXT</STRONG> Bit-mask to extract a character
<STRONG>A_COLOR</STRONG> Bit-mask to extract a color (legacy routines)
These video attributes are supported by <STRONG>attr_on</STRONG> and related functions
(which also support the attributes recognized by <STRONG>attron</STRONG>, etc.):
<EM>Name</EM> <EM>Description</EM>
-----------------------------------------
<STRONG>WA_HORIZONTAL</STRONG> Horizontal highlight
<STRONG>WA_LEFT</STRONG> Left highlight
<STRONG>WA_LOW</STRONG> Low highlight
<STRONG>WA_RIGHT</STRONG> Right highlight
<STRONG>WA_TOP</STRONG> Top highlight
<STRONG>WA_VERTICAL</STRONG> 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 <STRONG>1</STRONG>.
</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
These functions may be macros:
<STRONG>attroff</STRONG>, <STRONG>wattroff</STRONG>, <STRONG>attron</STRONG>, <STRONG>wattron</STRONG>, <STRONG>attrset</STRONG>, <STRONG>wattrset</STRONG>, <STRONG>standend</STRONG>
and <STRONG>standout</STRONG>.
Color pair values can only be OR'd with attributes if the pair number
is less than 256. The alternate functions such as <STRONG>color_set</STRONG> 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.
</PRE><H2><a name="h2-HISTORY">HISTORY</a></H2><PRE>
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, <STRONG>attrset</STRONG> and <STRONG>attr_set</STRONG>
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 <EM>standout</EM> feature (often implemented as
bold and/or reverse video). The BSD curses library provided functions
<STRONG>standout</STRONG> and <STRONG>standend</STRONG> 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 <STRONG>A_</STRONG>
symbols for use by applications to manipulate the other attributes.
There are few useful references for the chronology.
Goodheart's book <EM>UNIX</EM> <EM>Curses</EM> <EM>Explained</EM> (1991) describes SVr3 (1987),
commenting on several functions:
<STRONG>o</STRONG> the <STRONG>attron</STRONG>, <STRONG>attroff</STRONG>, <STRONG>attrset</STRONG> functions (and most of the functions
found in SVr4 but not in BSD curses) were introduced by System V,
<STRONG>o</STRONG> the alternate character set feature with <STRONG>A_ALTCHARSET</STRONG> was added in
SVr2 and improved in SVr3 (by adding <STRONG>acs_map[]</STRONG>),
<STRONG>o</STRONG> <STRONG>start_color</STRONG> and related color-functions were introduced by System
V.3.2,
<STRONG>o</STRONG> pads, soft-keys were added in SVr3, and
Goodheart did not mention the background character or the <STRONG>cchar_t</STRONG> type.
Those are respectively SVr4 and X/Open features. He did mention the <STRONG>A_</STRONG>
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
<STRONG>chtype</STRONG> for <EM>characters</EM> and <EM>colors</EM>, and took into account the different
integer sizes (32-bit versus 64-bit).
This table showing the number of bits for <STRONG>A_COLOR</STRONG> and <STRONG>A_CHARTEXT</STRONG> 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.
<EM>Year</EM> <EM>System</EM> <EM>Arch</EM> <EM>Color</EM> <EM>Char</EM> <EM>Notes</EM>
----------------------------------------------------------------
1992 Solaris 5.2 32 6 17 SVr4 curses
1992 HPUX 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 <STRONG>chtype</STRONG>
Notes:
Regarding HP-UX,
<STRONG>o</STRONG> HP-UX 10.20 (1996) added support for 64-bit PA-RISC processors
in 1996.
<STRONG>o</STRONG> 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),
<STRONG>o</STRONG> These used 64-bit hardware. Like ncurses, the OSF/1 curses in-
terface is not customized for 32-bit and 64-bit versions.
<STRONG>o</STRONG> Unlike other systems which evolved from AT&T code, OSF/1 provid-
ed a new implementation for X/Open curses.
Regarding Solaris,
<STRONG>o</STRONG> The initial release of Solaris was in 1992.
<STRONG>o</STRONG> The <EM>xpg4</EM> (X/Open) curses was developed by MKS from 1990 to 1995.
Sun's copyright began in 1996.
<STRONG>o</STRONG> 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,
<STRONG>o</STRONG> Development of the curses library began in 1991, stopped in
2000.
<STRONG>o</STRONG> Color support was added in 1998.
<STRONG>o</STRONG> The library uses only <STRONG>chtype</STRONG> (no <STRONG>cchar_t</STRONG>).
Once X/Open curses was adopted in the mid-1990s, the constraint of a
32-bit interface with many colors and wide-characters for <STRONG>chtype</STRONG> became
a moot point. The <STRONG>cchar_t</STRONG> structure (whose size and members are not
specified in X/Open Curses) could be extended as needed.
Other interfaces are rarely used now:
<STRONG>o</STRONG> BSD curses was improved slightly in 1993/1994 using Keith Bostic's
modification to make the library 8-bit clean for <STRONG>nvi</STRONG>. He moved
<EM>standout</EM> attribute to a structure member.
The resulting 4.4BSD curses was replaced by ncurses over the next
ten years.
<STRONG>o</STRONG> U/Win is rarely used now.
</PRE><H2><a name="h2-EXTENSIONS">EXTENSIONS</a></H2><PRE>
This implementation provides the <STRONG>A_ITALIC</STRONG> attribute for terminals which
have the <STRONG>enter_italics_mode</STRONG> (<STRONG>sitm</STRONG>) and <STRONG>exit_italics_mode</STRONG> (<STRONG>ritm</STRONG>) capa-
bilities. Italics are not mentioned in X/Open Curses. Unlike the oth-
er video attributes, <STRONG>A_ITALIC</STRONG> is unrelated to the <STRONG>set_attributes</STRONG> capa-
bilities. This implementation makes the assumption that <STRONG>exit_attri-</STRONG>
<STRONG>bute_mode</STRONG> may also reset italics.
Each of the functions added by XSI Curses has a parameter <EM>opts</EM>, which
X/Open Curses still (after more than twenty years) documents as re-
served for future use, saying that it should be <STRONG>NULL</STRONG>. This implementa-
tion uses that parameter in ABI 6 for the functions which have a color-
pair parameter to support <EM>extended</EM> <EM>color</EM> <EM>pairs</EM>:
<STRONG>o</STRONG> For functions which modify the color, e.g., <STRONG>wattr_set</STRONG>, if <EM>opts</EM> is
set it is treated as a pointer to <STRONG>int</STRONG>, and used to set the color
pair instead of the <STRONG>short</STRONG> <EM>pair</EM> parameter.
<STRONG>o</STRONG> For functions which retrieve the color, e.g., <STRONG>wattr_get</STRONG>, if <EM>opts</EM> is
set it is treated as a pointer to <STRONG>int</STRONG>, and used to retrieve the
color pair as an <STRONG>int</STRONG> value, in addition retrieving it via the stan-
dard pointer to <STRONG>short</STRONG> parameter.
The remaining functions which have <EM>opts</EM>, but do not manipulate color,
e.g., <STRONG>wattr_on</STRONG> and <STRONG>wattr_off</STRONG> are not used by this implementation except
to check that they are <STRONG>NULL</STRONG>.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
These functions are supported in the XSI Curses standard, Issue 4. The
standard defined the dedicated type for highlights, <STRONG>attr_t</STRONG>, which was
not defined in SVr4 curses. The functions taking <STRONG>attr_t</STRONG> 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 <STRONG>touchwin</STRONG> to force the screen to
match the updated attributes.
The XSI Curses standard states that whether the traditional functions
<STRONG>attron</STRONG>/<STRONG>attroff</STRONG>/<STRONG>attrset</STRONG> can manipulate attributes other than <STRONG>A_BLINK</STRONG>,
<STRONG>A_BOLD</STRONG>, <STRONG>A_DIM</STRONG>, <STRONG>A_REVERSE</STRONG>, <STRONG>A_STANDOUT</STRONG>, or <STRONG>A_UNDERLINE</STRONG> is "unspecified".
Under this implementation as well as SVr4 curses, these functions cor-
rectly manipulate all other highlights (specifically, <STRONG>A_ALTCHARSET</STRONG>,
<STRONG>A_PROTECT</STRONG>, and <STRONG>A_INVIS</STRONG>).
XSI Curses added these entry points:
<STRONG>attr_get</STRONG>, <STRONG>attr_on</STRONG>, <STRONG>attr_off</STRONG>, <STRONG>attr_set</STRONG>, <STRONG>wattr_on</STRONG>, <STRONG>wattr_off</STRONG>, <STRONG>wat-</STRONG>
<STRONG>tr_get</STRONG>, <STRONG>wattr_set</STRONG>
The new functions are intended to work with a new series of highlight
macros prefixed with <STRONG>WA_</STRONG>. The older macros have direct counterparts in
the newer set of names:
<EM>Name</EM> <EM>Description</EM>
------------------------------------------------------------
<STRONG>WA_NORMAL</STRONG> Normal display (no highlight)
<STRONG>WA_STANDOUT</STRONG> Best highlighting mode of the terminal.
<STRONG>WA_UNDERLINE</STRONG> Underlining
<STRONG>WA_REVERSE</STRONG> Reverse video
<STRONG>WA_BLINK</STRONG> Blinking
<STRONG>WA_DIM</STRONG> Half bright
<STRONG>WA_BOLD</STRONG> Extra bright or bold
<STRONG>WA_ALTCHARSET</STRONG> 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.:
<STRONG>o</STRONG> The XSI curses standard specifies that each pair of corresponding
<STRONG>A_</STRONG> and <STRONG>WA_</STRONG>-using functions operates on the same current-highlight
information.
<STRONG>o</STRONG> However, in some implementations, those symbols have unrelated val-
ues.
For example, the Solaris <EM>xpg4</EM> (X/Open) curses declares <STRONG>attr_t</STRONG> to be
an unsigned short integer (16-bits), while <STRONG>chtype</STRONG> is a unsigned in-
teger (32-bits). The <STRONG>WA_</STRONG> symbols in this case are different from
the <STRONG>A_</STRONG> symbols because they are used for a smaller datatype which
does not represent <STRONG>A_CHARTEXT</STRONG> or <STRONG>A_COLOR</STRONG>.
In this implementation (as in many others), the values happen to be
the same because it simplifies copying information between <STRONG>chtype</STRONG>
and <STRONG>cchar_t</STRONG> variables.
The XSI standard extended conformance level adds new highlights <STRONG>A_HORI-</STRONG>
<STRONG>ZONTAL</STRONG>, <STRONG>A_LEFT</STRONG>, <STRONG>A_LOW</STRONG>, <STRONG>A_RIGHT</STRONG>, <STRONG>A_TOP</STRONG>, <STRONG>A_VERTICAL</STRONG> (and corresponding
<STRONG>WA_</STRONG> macros for each). As of August 2013, no known terminal provides
these highlights (i.e., via the <STRONG>sgr1</STRONG> capability).
</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
All routines return the integer <STRONG>OK</STRONG> on success, or <STRONG>ERR</STRONG> on failure.
X/Open does not define any error conditions.
This implementation
<STRONG>o</STRONG> returns an error if the window pointer is null.
<STRONG>o</STRONG> returns an error if the color pair parameter for <STRONG>wcolor_set</STRONG> is out-
side the range 0..COLOR_PAIRS-1.
<STRONG>o</STRONG> does not return an error if either of the parameters of <STRONG>wattr_get</STRONG>
used for retrieving attribute or color-pair values is <STRONG>NULL</STRONG>.
Functions with a "mv" prefix first perform a cursor movement using
<STRONG>wmove</STRONG>, and return an error if the position is outside the window, or if
the window pointer is null.
</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
<STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>, <STRONG><A HREF="curs_addstr.3x.html">curs_addstr(3x)</A></STRONG>, <STRONG><A HREF="curs_bkgd.3x.html">curs_bkgd(3x)</A></STRONG>,
<STRONG><A HREF="curs_printw.3x.html">curs_printw(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>
<STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
<ul>
<li><a href="#h3-Window-attributes">Window attributes</a></li>
<li><a href="#h3-Legacy-window-attributes">Legacy window attributes</a></li>
<li><a href="#h3-Change-character-rendition">Change character rendition</a></li>
<li><a href="#h3-Change-window-color">Change window color</a></li>
<li><a href="#h3-Standout">Standout</a></li>
</ul>
</li>
<li><a href="#h2-VIDEO-ATTRIBUTES">VIDEO ATTRIBUTES</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
<li><a href="#h2-HISTORY">HISTORY</a></li>
<li><a href="#h2-EXTENSIONS">EXTENSIONS</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
</div>
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