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64 <H1 class="no-header">curs_attr 3x 2023-07-01 ncurses 6.4 Library calls</H1>
66 <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG> Library calls <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>
71 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
72 <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>,
73 <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>,
74 <STRONG>wchgat</STRONG>, <STRONG>mvchgat</STRONG>, <STRONG>mvwchgat</STRONG>, <STRONG>color_set</STRONG>, <STRONG>wcolor_set</STRONG>, <STRONG>standend</STRONG>, <STRONG>wstandend</STRONG>,
75 <STRONG>standout</STRONG>, <STRONG>wstandout</STRONG> - <STRONG>curses</STRONG> character and window attribute control
79 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
80 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
82 <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>
83 <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>
84 <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>
85 <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>
87 <STRONG>int</STRONG> <STRONG>attr_off(attr_t</STRONG> <EM>attrs</EM><STRONG>,</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM><STRONG>);</STRONG>
88 <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>
89 <STRONG>int</STRONG> <STRONG>attr_on(attr_t</STRONG> <EM>attrs</EM><STRONG>,</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM><STRONG>);</STRONG>
90 <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>
92 <STRONG>int</STRONG> <STRONG>attroff(int</STRONG> <EM>attrs);</EM>
93 <STRONG>int</STRONG> <STRONG>wattroff(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>attrs</EM><STRONG>);</STRONG>
94 <STRONG>int</STRONG> <STRONG>attron(int</STRONG> <EM>attrs</EM><STRONG>);</STRONG>
95 <STRONG>int</STRONG> <STRONG>wattron(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>attrs</EM><STRONG>);</STRONG>
96 <STRONG>int</STRONG> <STRONG>attrset(int</STRONG> <EM>attrs</EM><STRONG>);</STRONG>
97 <STRONG>int</STRONG> <STRONG>wattrset(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>attrs</EM><STRONG>);</STRONG>
99 <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>
100 <STRONG>int</STRONG> <STRONG>wchgat(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG>
101 <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>
102 <STRONG>int</STRONG> <STRONG>mvchgat(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG>
103 <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>
104 <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>
105 <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>
107 <STRONG>int</STRONG> <STRONG>color_set(short</STRONG> <EM>pair</EM><STRONG>,</STRONG> <STRONG>void*</STRONG> <EM>opts</EM><STRONG>);</STRONG>
108 <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>
110 <STRONG>int</STRONG> <STRONG>standend(void);</STRONG>
111 <STRONG>int</STRONG> <STRONG>wstandend(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG>
112 <STRONG>int</STRONG> <STRONG>standout(void);</STRONG>
113 <STRONG>int</STRONG> <STRONG>wstandout(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG>
116 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
117 These routines manipulate the current attributes of the named window,
118 which then apply to all characters that are written into the window
119 with <STRONG>waddch</STRONG>, <STRONG>waddstr</STRONG> and <STRONG>wprintw</STRONG>. Attributes are a property of the
120 character, and move with the character through any scrolling and in-
121 sert/delete line/character operations. To the extent possible, they
122 are displayed as appropriate modifications to the graphic rendition of
123 characters put on the screen.
125 These routines do not affect the attributes used when erasing portions
126 of the window. See <STRONG><A HREF="curs_bkgd.3x.html">curs_bkgd(3x)</A></STRONG> for functions which modify the at-
127 tributes used for erasing and clearing.
129 Routines which do not have a <STRONG>WINDOW*</STRONG> parameter apply to <STRONG>stdscr</STRONG>. For
130 example, <STRONG>attr_set</STRONG> is the <STRONG>stdscr</STRONG> variant of <STRONG>wattr_set</STRONG>.
133 </PRE><H3><a name="h3-Window-attributes">Window attributes</a></H3><PRE>
134 There are two sets of functions:
136 <STRONG>o</STRONG> functions for manipulating the window attributes and color: <STRONG>wat-</STRONG>
137 <STRONG>tr_set</STRONG> and <STRONG>wattr_get</STRONG>.
139 <STRONG>o</STRONG> functions for manipulating only the window attributes (not color):
140 <STRONG>wattr_on</STRONG> and <STRONG>wattr_off</STRONG>.
142 The <STRONG>wattr_set</STRONG> function sets the current attributes of the given window
143 to <EM>attrs</EM>, with color specified by <EM>pair</EM>.
145 Use <STRONG>wattr_get</STRONG> to retrieve attributes for the given window.
147 Use <STRONG>attr_on</STRONG> and <STRONG>wattr_on</STRONG> to turn on window attributes, i.e., values
148 OR'd together in <EM>attr</EM>, without affecting other attributes. Use <STRONG>at-</STRONG>
149 <STRONG>tr_off</STRONG> and <STRONG>wattr_off</STRONG> to turn off window attributes, again values OR'd
150 together in <EM>attr</EM>, without affecting other attributes.
153 </PRE><H3><a name="h3-Legacy-window-attributes">Legacy window attributes</a></H3><PRE>
154 The X/Open window attribute routines which <EM>set</EM> or <EM>get</EM>, turn <EM>on</EM> or <EM>off</EM>
155 are extensions of older routines which assume that color pairs are OR'd
156 into the attribute parameter. These newer routines use similar names,
157 because X/Open simply added an underscore (<STRONG>_</STRONG>) for the newer names.
159 The <STRONG>int</STRONG> datatype used in the legacy routines is treated as if it is the
160 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-
161 tributes (such as bold, reverse), as well as a few bits for color.
162 Those bits correspond to the <STRONG>A_COLOR</STRONG> symbol. The <STRONG>COLOR_PAIR</STRONG> macro pro-
163 vides a value which can be OR'd into the attribute parameter. For ex-
164 ample, as long as that value fits into the <STRONG>A_COLOR</STRONG> mask, then these
165 calls produce similar results:
167 attrset(A_BOLD | COLOR_PAIR(<EM>pair</EM>));
168 attr_set(A_BOLD, <EM>pair</EM>, NULL);
170 However, if the value does not fit, then the <STRONG>COLOR_PAIR</STRONG> macro uses only
171 the bits that fit. For example, because in ncurses <STRONG>A_COLOR</STRONG> has eight
172 (8) bits, then <STRONG>COLOR_PAIR(</STRONG><EM>259</EM><STRONG>)</STRONG> is 4 (i.e., 259 is 4 more than the limit
175 The <STRONG>PAIR_NUMBER</STRONG> macro extracts a pair number from an <STRONG>int</STRONG> (or <STRONG>chtype</STRONG>).
176 For example, the <EM>input</EM> and <EM>output</EM> values in these statements would be
179 int value = A_BOLD | COLOR_PAIR(<EM>input</EM>);
180 int <EM>output</EM> = PAIR_NUMBER(value);
182 The <STRONG>attrset</STRONG> routine is a legacy feature predating SVr4 curses but kept
183 in X/Open Curses for the same reason that SVr4 curses kept it: compati-
186 The remaining <STRONG>attr</STRONG>* functions operate exactly like the corresponding
187 <STRONG>attr_</STRONG>* functions, except that they take arguments of type <STRONG>int</STRONG> rather
188 than <STRONG>attr_t</STRONG>.
190 There is no corresponding <STRONG>attrget</STRONG> function as such in X/Open Curses,
191 although ncurses provides <STRONG>getattrs</STRONG> (see <STRONG><A HREF="curs_legacy.3x.html">curs_legacy(3x)</A></STRONG>).
194 </PRE><H3><a name="h3-Change-character-rendition">Change character rendition</a></H3><PRE>
195 The routine <STRONG>chgat</STRONG> changes the attributes of a given number of charac-
196 ters starting at the current cursor location of <STRONG>stdscr</STRONG>. It does not
197 update the cursor and does not perform wrapping. A character count of
198 -1 or greater than the remaining window width means to change at-
199 tributes all the way to the end of the current line. The <STRONG>wchgat</STRONG> func-
200 tion generalizes this to any window; the <STRONG>mvwchgat</STRONG> function does a cur-
201 sor move before acting.
203 In these functions, the color <EM>pair</EM> argument is a color-pair index (as
204 in the first argument of <STRONG>init_pair</STRONG>, see <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>).
207 </PRE><H3><a name="h3-Change-window-color">Change window color</a></H3><PRE>
208 The routine <STRONG>color_set</STRONG> sets the current color of the given window to the
209 foreground/background combination described by the color <EM>pair</EM> parame-
213 </PRE><H3><a name="h3-Standout">Standout</a></H3><PRE>
214 The routine <STRONG>standout</STRONG> is the same as <STRONG>attron(A_STANDOUT)</STRONG>. The routine
215 <STRONG>standend</STRONG> is the same as <STRONG>attrset(A_NORMAL)</STRONG> or <STRONG>attrset(0)</STRONG>, that is, it
216 turns off all attributes.
218 X/Open does not mark these "restricted", because
220 <STRONG>o</STRONG> they have well established legacy use, and
222 <STRONG>o</STRONG> there is no ambiguity about the way the attributes might be com-
223 bined with a color pair.
226 </PRE><H2><a name="h2-VIDEO-ATTRIBUTES">VIDEO ATTRIBUTES</a></H2><PRE>
227 The following video attributes, defined in <STRONG><curses.h></STRONG>, can be passed to
228 the routines <STRONG>attron</STRONG>, <STRONG>attroff</STRONG>, and <STRONG>attrset</STRONG>, or OR'd with the characters
229 passed to <STRONG>addch</STRONG> (see <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>).
231 <STRONG>Name</STRONG> <STRONG>Description</STRONG>
232 -----------------------------------------------------------------
233 <STRONG>A_NORMAL</STRONG> Normal display (no highlight)
234 <STRONG>A_STANDOUT</STRONG> Best highlighting mode of the terminal.
235 <STRONG>A_UNDERLINE</STRONG> Underlining
236 <STRONG>A_REVERSE</STRONG> Reverse video
237 <STRONG>A_BLINK</STRONG> Blinking
238 <STRONG>A_DIM</STRONG> Half bright
239 <STRONG>A_BOLD</STRONG> Extra bright or bold
240 <STRONG>A_PROTECT</STRONG> Protected mode
241 <STRONG>A_INVIS</STRONG> Invisible or blank mode
242 <STRONG>A_ALTCHARSET</STRONG> Alternate character set
243 <STRONG>A_ITALIC</STRONG> Italics (non-X/Open extension)
244 <STRONG>A_CHARTEXT</STRONG> Bit-mask to extract a character
245 <STRONG>A_COLOR</STRONG> Bit-mask to extract a color (legacy routines)
247 These video attributes are supported by <STRONG>attr_on</STRONG> and related functions
248 (which also support the attributes recognized by <STRONG>attron</STRONG>, etc.):
250 <STRONG>Name</STRONG> <STRONG>Description</STRONG>
251 -----------------------------------------
252 <STRONG>WA_HORIZONTAL</STRONG> Horizontal highlight
253 <STRONG>WA_LEFT</STRONG> Left highlight
254 <STRONG>WA_LOW</STRONG> Low highlight
255 <STRONG>WA_RIGHT</STRONG> Right highlight
256 <STRONG>WA_TOP</STRONG> Top highlight
257 <STRONG>WA_VERTICAL</STRONG> Vertical highlight
259 The return values of many of these routines are not meaningful (they
260 are implemented as macro-expanded assignments and simply return their
261 argument). The SVr4 manual page claims (falsely) that these routines
262 always return <STRONG>1</STRONG>.
265 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
266 These functions may be macros:
268 <STRONG>attroff</STRONG>, <STRONG>wattroff</STRONG>, <STRONG>attron</STRONG>, <STRONG>wattron</STRONG>, <STRONG>attrset</STRONG>, <STRONG>wattrset</STRONG>, <STRONG>standend</STRONG>
269 and <STRONG>standout</STRONG>.
271 Color pair values can only be OR'd with attributes if the pair number
272 is less than 256. The alternate functions such as <STRONG>color_set</STRONG> can pass a
273 color pair value directly. However, ncurses ABI 4 and 5 simply OR this
274 value within the alternate functions. You must use ncurses ABI 6 to
275 support more than 256 color pairs.
278 </PRE><H2><a name="h2-HISTORY">HISTORY</a></H2><PRE>
279 X/Open Curses is largely based on SVr4 curses, adding support for
280 "wide-characters" (not specific to Unicode). Some of the X/Open dif-
281 ferences from SVr4 curses address the way video attributes can be ap-
282 plied to wide-characters. But aside from that, <STRONG>attrset</STRONG> and <STRONG>attr_set</STRONG>
283 are similar. SVr4 curses provided the basic features for manipulating
284 video attributes. However, earlier versions of curses provided a part
287 As seen in 2.8BSD, curses assumed 7-bit characters, using the eighth
288 bit of a byte to represent the <EM>standout</EM> feature (often implemented as
289 bold and/or reverse video). The BSD curses library provided functions
290 <STRONG>standout</STRONG> and <STRONG>standend</STRONG> which were carried along into X/Open Curses due
291 to their pervasive use in legacy applications.
293 Some terminals in the 1980s could support a variety of video at-
294 tributes, although the BSD curses library could do nothing with those.
295 System V (1983) provided an improved curses library. It defined the <STRONG>A_</STRONG>
296 symbols for use by applications to manipulate the other attributes.
297 There are few useful references for the chronology.
299 Goodheart's book <EM>UNIX</EM> <EM>Curses</EM> <EM>Explained</EM> (1991) describes SVr3 (1987),
300 commenting on several functions:
302 <STRONG>o</STRONG> the <STRONG>attron</STRONG>, <STRONG>attroff</STRONG>, <STRONG>attrset</STRONG> functions (and most of the functions
303 found in SVr4 but not in BSD curses) were introduced by System V,
305 <STRONG>o</STRONG> the alternate character set feature with <STRONG>A_ALTCHARSET</STRONG> was added in
306 SVr2 and improved in SVr3 (by adding <STRONG>acs_map[]</STRONG>),
308 <STRONG>o</STRONG> <STRONG>start_color</STRONG> and related color-functions were introduced by System
311 <STRONG>o</STRONG> pads, soft-keys were added in SVr3, and
313 Goodheart did not mention the background character or the <STRONG>cchar_t</STRONG> type.
314 Those are respectively SVr4 and X/Open features. He did mention the <STRONG>A_</STRONG>
315 constants, but did not indicate their values. Those were not the same
316 in different systems, even for those marked as System V.
318 Different Unix systems used different sizes for the bit-fields in
319 <STRONG>chtype</STRONG> for <EM>characters</EM> and <EM>colors</EM>, and took into account the different
320 integer sizes (32-bit versus 64-bit).
322 This table showing the number of bits for <STRONG>A_COLOR</STRONG> and <STRONG>A_CHARTEXT</STRONG> was
323 gleaned from the curses header files for various operating systems and
324 architectures. The inferred architecture and notes reflect the format
325 and size of the defined constants as well as clues such as the alter-
326 nate character set implementation. A 32-bit library can be used on a
327 64-bit system, but not necessarily the reverse.
329 <STRONG>Year</STRONG> <STRONG>System</STRONG> <STRONG>Arch</STRONG> <STRONG>Color</STRONG> <STRONG>Char</STRONG> <STRONG>Notes</STRONG>
330 ----------------------------------------------------------------
331 1992 Solaris 5.2 32 6 17 SVr4 curses
332 1992 HPUX 9 32 no 8 SVr2 curses
333 1992 AIX 3.2 32 no 23 SVr2 curses
334 1994 OSF/1 r3 32 no 23 SVr2 curses
335 1995 HP-UX 10.00 32 6 16 SVr3 "curses_colr"
336 1995 HP-UX 10.00 32 6 8 SVr4, X/Open curses
337 1995 Solaris 5.4 32/64 7 16 X/Open curses
338 1996 AIX 4.2 32 7 16 X/Open curses
339 1996 OSF/1 r4 32 6 16 X/Open curses
341 1997 HP-UX 11.00 32 6 8 X/Open curses
342 2000 U/Win 32/64 7/31 16 uses <STRONG>chtype</STRONG>
348 <STRONG>o</STRONG> HP-UX 10.20 (1996) added support for 64-bit PA-RISC processors
351 <STRONG>o</STRONG> HP-UX 10.30 (1997) marked "curses_colr" obsolete. That version
352 of curses was dropped with HP-UX 11.30 in 2006.
354 Regarding OSF/1 (and Tru64),
356 <STRONG>o</STRONG> These used 64-bit hardware. Like ncurses, the OSF/1 curses in-
357 terface is not customized for 32-bit and 64-bit versions.
359 <STRONG>o</STRONG> Unlike other systems which evolved from AT&T code, OSF/1 provid-
360 ed a new implementation for X/Open curses.
364 <STRONG>o</STRONG> The initial release of Solaris was in 1992.
366 <STRONG>o</STRONG> The <EM>xpg4</EM> (X/Open) curses was developed by MKS from 1990 to 1995.
367 Sun's copyright began in 1996.
369 <STRONG>o</STRONG> Sun updated the X/Open curses interface after 64-bit support was
370 introduced in 1997, but did not modify the SVr4 curses inter-
375 <STRONG>o</STRONG> Development of the curses library began in 1991, stopped in
378 <STRONG>o</STRONG> Color support was added in 1998.
380 <STRONG>o</STRONG> The library uses only <STRONG>chtype</STRONG> (no <STRONG>cchar_t</STRONG>).
382 Once X/Open curses was adopted in the mid-1990s, the constraint of a
383 32-bit interface with many colors and wide-characters for <STRONG>chtype</STRONG> became
384 a moot point. The <STRONG>cchar_t</STRONG> structure (whose size and members are not
385 specified in X/Open Curses) could be extended as needed.
387 Other interfaces are rarely used now:
389 <STRONG>o</STRONG> BSD curses was improved slightly in 1993/1994 using Keith Bostic's
390 modification to make the library 8-bit clean for <STRONG>nvi(1)</STRONG>. He moved
391 <EM>standout</EM> attribute to a structure member.
393 The resulting 4.4BSD curses was replaced by ncurses over the next
396 <STRONG>o</STRONG> U/Win is rarely used now.
399 </PRE><H2><a name="h2-EXTENSIONS">EXTENSIONS</a></H2><PRE>
400 This implementation provides the <STRONG>A_ITALIC</STRONG> attribute for terminals which
401 have the <STRONG>enter_italics_mode</STRONG> (<STRONG>sitm</STRONG>) and <STRONG>exit_italics_mode</STRONG> (<STRONG>ritm</STRONG>) capa-
402 bilities. Italics are not mentioned in X/Open Curses. Unlike the oth-
403 er video attributes, <STRONG>A_ITALIC</STRONG> is unrelated to the <STRONG>set_attributes</STRONG> capa-
404 bilities. This implementation makes the assumption that <STRONG>exit_attri-</STRONG>
405 <STRONG>bute_mode</STRONG> may also reset italics.
407 Each of the functions added by XSI Curses has a parameter <EM>opts</EM>, which
408 X/Open Curses still (after more than twenty years) documents as re-
409 served for future use, saying that it should be <STRONG>NULL</STRONG>. This implementa-
410 tion uses that parameter in ABI 6 for the functions which have a color-
411 pair parameter to support <EM>extended</EM> <EM>color</EM> <EM>pairs</EM>:
413 <STRONG>o</STRONG> For functions which modify the color, e.g., <STRONG>wattr_set</STRONG> and <STRONG>wattr_on</STRONG>,
414 if <EM>opts</EM> is set it is treated as a pointer to <STRONG>int</STRONG>, and used to set
415 the color pair instead of the <STRONG>short</STRONG> <EM>pair</EM> parameter.
417 <STRONG>o</STRONG> For functions which retrieve the color, e.g., <STRONG>wattr_get</STRONG>, if <EM>opts</EM> is
418 set it is treated as a pointer to <STRONG>int</STRONG>, and used to retrieve the
419 color pair as an <STRONG>int</STRONG> value, in addition to retrieving it via the
420 standard pointer to <STRONG>short</STRONG> parameter.
422 <STRONG>o</STRONG> For functions which turn attributes off, e.g., <STRONG>wattr_off</STRONG>, the <EM>opts</EM>
423 parameter is ignored except except to check that it is <STRONG>NULL</STRONG>.
426 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
427 These functions are supported in the XSI Curses standard, Issue 4. The
428 standard defined the dedicated type for highlights, <STRONG>attr_t</STRONG>, which was
429 not defined in SVr4 curses. The functions taking <STRONG>attr_t</STRONG> arguments were
430 not supported under SVr4.
432 Very old versions of this library did not force an update of the screen
433 when changing the attributes. Use <STRONG>touchwin</STRONG> to force the screen to
434 match the updated attributes.
436 The XSI Curses standard states that whether the traditional functions
437 <STRONG>attron</STRONG>/<STRONG>attroff</STRONG>/<STRONG>attrset</STRONG> can manipulate attributes other than <STRONG>A_BLINK</STRONG>,
438 <STRONG>A_BOLD</STRONG>, <STRONG>A_DIM</STRONG>, <STRONG>A_REVERSE</STRONG>, <STRONG>A_STANDOUT</STRONG>, or <STRONG>A_UNDERLINE</STRONG> is "unspecified".
439 Under this implementation as well as SVr4 curses, these functions cor-
440 rectly manipulate all other highlights (specifically, <STRONG>A_ALTCHARSET</STRONG>,
441 <STRONG>A_PROTECT</STRONG>, and <STRONG>A_INVIS</STRONG>).
443 XSI Curses added these entry points:
445 <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>
446 <STRONG>tr_get</STRONG>, <STRONG>wattr_set</STRONG>
448 The new functions are intended to work with a new series of highlight
449 macros prefixed with <STRONG>WA_</STRONG>. The older macros have direct counterparts in
450 the newer set of names:
452 <STRONG>Name</STRONG> <STRONG>Description</STRONG>
453 ------------------------------------------------------------
454 <STRONG>WA_NORMAL</STRONG> Normal display (no highlight)
455 <STRONG>WA_STANDOUT</STRONG> Best highlighting mode of the terminal.
456 <STRONG>WA_UNDERLINE</STRONG> Underlining
457 <STRONG>WA_REVERSE</STRONG> Reverse video
458 <STRONG>WA_BLINK</STRONG> Blinking
459 <STRONG>WA_DIM</STRONG> Half bright
460 <STRONG>WA_BOLD</STRONG> Extra bright or bold
461 <STRONG>WA_ALTCHARSET</STRONG> Alternate character set
463 XSI curses does not assign values to these symbols, nor does it state
464 whether or not they are related to the similarly-named A_NORMAL, etc.:
466 <STRONG>o</STRONG> The XSI curses standard specifies that each pair of corresponding
467 <STRONG>A_</STRONG> and <STRONG>WA_</STRONG>-using functions operates on the same current-highlight
470 <STRONG>o</STRONG> However, in some implementations, those symbols have unrelated val-
473 For example, the Solaris <EM>xpg4</EM> (X/Open) curses declares <STRONG>attr_t</STRONG> to be
474 an unsigned short integer (16-bits), while <STRONG>chtype</STRONG> is a unsigned in-
475 teger (32-bits). The <STRONG>WA_</STRONG> symbols in this case are different from
476 the <STRONG>A_</STRONG> symbols because they are used for a smaller datatype which
477 does not represent <STRONG>A_CHARTEXT</STRONG> or <STRONG>A_COLOR</STRONG>.
479 In this implementation (as in many others), the values happen to be
480 the same because it simplifies copying information between <STRONG>chtype</STRONG>
481 and <STRONG>cchar_t</STRONG> variables.
483 <STRONG>o</STRONG> Because ncurses's <STRONG>attr_t</STRONG> can hold a color pair (in the <STRONG>A_COLOR</STRONG>
484 field), a call to <STRONG>wattr_on</STRONG>, <STRONG>wattr_off</STRONG>, or <STRONG>wattr_set</STRONG> may alter the
485 window's color. If the color pair information in the attribute pa-
486 rameter is zero, no change is made to the window's color.
488 This is consistent with SVr4 curses; X/Open Curses does not specify
491 The XSI standard extended conformance level adds new highlights <STRONG>A_HORI-</STRONG>
492 <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
493 <STRONG>WA_</STRONG> macros for each). As of August 2013, no known terminal provides
494 these highlights (i.e., via the <STRONG>sgr1</STRONG> capability).
497 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
498 All routines return the integer <STRONG>OK</STRONG> on success, or <STRONG>ERR</STRONG> on failure.
500 X/Open does not define any error conditions.
504 <STRONG>o</STRONG> returns an error if the window pointer is null.
506 <STRONG>o</STRONG> returns an error if the color pair parameter for <STRONG>wcolor_set</STRONG> is out-
507 side the range 0..COLOR_PAIRS-1.
509 <STRONG>o</STRONG> does not return an error if either of the parameters of <STRONG>wattr_get</STRONG>
510 used for retrieving attribute or color-pair values is <STRONG>NULL</STRONG>.
512 Functions with a "mv" prefix first perform a cursor movement using
513 <STRONG>wmove</STRONG>, and return an error if the position is outside the window, or if
514 the window pointer is null.
517 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
518 <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>,
519 <STRONG><A HREF="curs_printw.3x.html">curs_printw(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>
523 ncurses 6.4 2023-07-01 <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>
527 <li><a href="#h2-NAME">NAME</a></li>
528 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
529 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
531 <li><a href="#h3-Window-attributes">Window attributes</a></li>
532 <li><a href="#h3-Legacy-window-attributes">Legacy window attributes</a></li>
533 <li><a href="#h3-Change-character-rendition">Change character rendition</a></li>
534 <li><a href="#h3-Change-window-color">Change window color</a></li>
535 <li><a href="#h3-Standout">Standout</a></li>
538 <li><a href="#h2-VIDEO-ATTRIBUTES">VIDEO ATTRIBUTES</a></li>
539 <li><a href="#h2-NOTES">NOTES</a></li>
540 <li><a href="#h2-HISTORY">HISTORY</a></li>
541 <li><a href="#h2-EXTENSIONS">EXTENSIONS</a></li>
542 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
543 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
544 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>