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39<link rel="author" href="mailto:bug-ncurses@gnu.org"> 40 41</HEAD> 42<BODY> 43<H1 class="no-header">curs_attr 3x 2024-04-27 ncurses 6.5 Library calls</H1> 44<PRE> 45<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> 46 47 48 49 50</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE> 51 <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>, 52 <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>, 53 <STRONG>wchgat</STRONG>, <STRONG>mvchgat</STRONG>, <STRONG>mvwchgat</STRONG>, <STRONG>color_set</STRONG>, <STRONG>wcolor_set</STRONG>, <STRONG>standend</STRONG>, <STRONG>wstandend</STRONG>, 54 <STRONG>standout</STRONG>, <STRONG>wstandout</STRONG> - manipulate attributes of character cells in 55 <EM>curses</EM> windows 56 57 58</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE> 59 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG> 60 61 <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> 62 <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> 63 <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> 64 <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> 65 66 <STRONG>int</STRONG> <STRONG>attr_off(attr_t</STRONG> <EM>attrs</EM><STRONG>,</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM><STRONG>);</STRONG> 67 <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> 68 <STRONG>int</STRONG> <STRONG>attr_on(attr_t</STRONG> <EM>attrs</EM><STRONG>,</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM><STRONG>);</STRONG> 69 <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> 70 71 <STRONG>int</STRONG> <STRONG>attroff(int</STRONG> <EM>attrs</EM><STRONG>);</STRONG> 72 <STRONG>int</STRONG> <STRONG>wattroff(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>attrs</EM><STRONG>);</STRONG> 73 <STRONG>int</STRONG> <STRONG>attron(int</STRONG> <EM>attrs</EM><STRONG>);</STRONG> 74 <STRONG>int</STRONG> <STRONG>wattron(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>attrs</EM><STRONG>);</STRONG> 75 <STRONG>int</STRONG> <STRONG>attrset(int</STRONG> <EM>attrs</EM><STRONG>);</STRONG> 76 <STRONG>int</STRONG> <STRONG>wattrset(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>attrs</EM><STRONG>);</STRONG> 77 78 <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> 79 <STRONG>int</STRONG> <STRONG>wchgat(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> 80 <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> 81 <STRONG>int</STRONG> <STRONG>mvchgat(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> 82 <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> 83 <STRONG>int</STRONG> <STRONG>mvwchgat(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> 84 <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> 85 86 <STRONG>int</STRONG> <STRONG>color_set(short</STRONG> <EM>pair</EM><STRONG>,</STRONG> <STRONG>void*</STRONG> <EM>opts</EM><STRONG>);</STRONG> 87 <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>);</STRONG> 88 89 <STRONG>int</STRONG> <STRONG>standend(void);</STRONG> 90 <STRONG>int</STRONG> <STRONG>wstandend(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG> 91 <STRONG>int</STRONG> <STRONG>standout(void);</STRONG> 92 <STRONG>int</STRONG> <STRONG>wstandout(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG> 93 94 95</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE> 96 These routines manipulate the current attributes of the named window, 97 which then apply to all characters that are written into the window 98 with <STRONG>waddch</STRONG>, <STRONG>waddstr</STRONG> and <STRONG>wprintw</STRONG>. Attributes are a property of the 99 character, and move with the character through any scrolling and 100 insert/delete line/character operations. To the extent possible, they 101 are displayed as appropriate modifications to the graphic rendition of 102 characters put on the screen. 103 104 These routines do not affect the attributes used when erasing portions 105 of the window. See <STRONG><A HREF="curs_bkgd.3x.html">curs_bkgd(3x)</A></STRONG> for functions which modify the 106 attributes used for erasing and clearing. 107 108 109</PRE><H3><a name="h3-Window-Attributes">Window Attributes</a></H3><PRE> 110 There are two sets of functions: 111 112 <STRONG>o</STRONG> functions for manipulating the window attributes and color: 113 <STRONG>wattr_set</STRONG> and <STRONG>wattr_get</STRONG>. 114 115 <STRONG>o</STRONG> functions for manipulating only the window attributes (not color): 116 <STRONG>wattr_on</STRONG> and <STRONG>wattr_off</STRONG>. 117 118 The <STRONG>wattr_set</STRONG> function sets the current attributes of the given window 119 to <EM>attrs</EM>, with color specified by <EM>pair</EM>. 120 121 Use <STRONG>wattr_get</STRONG> to retrieve attributes for the given window. 122 123 Use <STRONG>attr_on</STRONG> and <STRONG>wattr_on</STRONG> to turn on window attributes, i.e., values 124 OR'd together in <EM>attr</EM>, without affecting other attributes. Use 125 <STRONG>attr_off</STRONG> and <STRONG>wattr_off</STRONG> to turn off window attributes, again values OR'd 126 together in <EM>attr</EM>, without affecting other attributes. 127 128 129</PRE><H3><a name="h3-Legacy-Window-Attributes">Legacy Window Attributes</a></H3><PRE> 130 The X/Open window attribute routines which <EM>set</EM> or <EM>get</EM>, turn <EM>on</EM> or <EM>off</EM> 131 are extensions of older routines which assume that color pairs are OR'd 132 into the attribute parameter. These newer routines use similar names, 133 because X/Open simply added an underscore (<STRONG>_</STRONG>) for the newer names. 134 135 The <STRONG>int</STRONG> datatype used in the legacy routines is treated as if it is the 136 same size as <STRONG>chtype</STRONG> (used by <STRONG><A HREF="curs_addch.3x.html">addch(3x)</A></STRONG>). It holds the common video 137 attributes (such as bold, reverse), as well as a few bits for color. 138 Those bits correspond to the <STRONG>A_COLOR</STRONG> symbol. The <STRONG>COLOR_PAIR</STRONG> macro 139 provides a value which can be OR'd into the attribute parameter. For 140 example, as long as that value fits into the <STRONG>A_COLOR</STRONG> mask, then these 141 calls produce similar results: 142 143 attrset(A_BOLD | COLOR_PAIR(<EM>pair</EM>)); 144 attr_set(A_BOLD, <EM>pair</EM>, NULL); 145 146 However, if the value does not fit, then the <STRONG>COLOR_PAIR</STRONG> macro uses only 147 the bits that fit. For example, because in <EM>ncurses</EM> <STRONG>A_COLOR</STRONG> has eight 148 (8) bits, then <STRONG>COLOR_PAIR(</STRONG><EM>259</EM><STRONG>)</STRONG> is 4 (i.e., 259 is 4 more than the limit 149 255). 150 151 The <STRONG>PAIR_NUMBER</STRONG> macro extracts a pair number from an <STRONG>int</STRONG> (or <STRONG>chtype</STRONG>). 152 For example, the <EM>input</EM> and <EM>output</EM> values in these statements would be 153 the same: 154 155 int value = A_BOLD | COLOR_PAIR(<EM>input</EM>); 156 int <EM>output</EM> = PAIR_NUMBER(value); 157 158 The <STRONG>attrset</STRONG> routine is a legacy feature predating SVr4 curses but kept 159 in X/Open Curses for the same reason that SVr4 curses kept it: 160 compatibility. 161 162 The remaining <STRONG>attr</STRONG>* functions operate exactly like the corresponding 163 <STRONG>attr_</STRONG>* functions, except that they take arguments of type <STRONG>int</STRONG> rather 164 than <STRONG>attr_t</STRONG>. 165 166 There is no corresponding <STRONG>attrget</STRONG> function as such in X/Open Curses, 167 although <EM>ncurses</EM> provides <STRONG>getattrs</STRONG> (see <STRONG><A HREF="curs_legacy.3x.html">curs_legacy(3x)</A></STRONG>). 168 169 170</PRE><H3><a name="h3-Change-Character-Rendition">Change Character Rendition</a></H3><PRE> 171 The routine <STRONG>chgat</STRONG> changes the attributes of a given number of 172 characters starting at the current cursor location of <STRONG>stdscr</STRONG>. It does 173 not update the cursor and does not perform wrapping. A character count 174 of -1 or greater than the remaining window width means to change 175 attributes all the way to the end of the current line. The <STRONG>wchgat</STRONG> 176 function generalizes this to any window; the <STRONG>mvwchgat</STRONG> function does a 177 cursor move before acting. 178 179 In these functions, the color <EM>pair</EM> argument is a color pair index (as 180 in the first argument of <STRONG>init_pair</STRONG>, see <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>). 181 182 183</PRE><H3><a name="h3-Change-Window-Color">Change Window Color</a></H3><PRE> 184 The routine <STRONG>color_set</STRONG> sets the current color of the given window to the 185 foreground/background combination described by the color <EM>pair</EM> 186 parameter. 187 188 189</PRE><H3><a name="h3-Standout">Standout</a></H3><PRE> 190 The routine <STRONG>standout</STRONG> is the same as <STRONG>attron(A_STANDOUT)</STRONG>. The routine 191 <STRONG>standend</STRONG> is the same as <STRONG>attrset(A_NORMAL)</STRONG> or <STRONG>attrset(0)</STRONG>, that is, it 192 turns off all attributes. 193 194 X/Open Curses does not mark these "restricted", because 195 196 <STRONG>o</STRONG> they have well established legacy use, and 197 198 <STRONG>o</STRONG> there is no ambiguity about the way the attributes might be 199 combined with a color pair. 200 201 202</PRE><H3><a name="h3-Video-Attributes">Video Attributes</a></H3><PRE> 203 The following video attributes, defined in <STRONG><curses.h></STRONG>, can be passed to 204 the routines <STRONG>attron</STRONG>, <STRONG>attroff</STRONG>, and <STRONG>attrset</STRONG>, or OR'd with the characters 205 passed to <STRONG>addch</STRONG> (see <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>). 206 207 <STRONG>Name</STRONG> <STRONG>Description</STRONG> 208 ----------------------------------------------------------------- 209 <STRONG>A_NORMAL</STRONG> Normal display (no highlight) 210 <STRONG>A_STANDOUT</STRONG> Best highlighting mode of the terminal 211 <STRONG>A_UNDERLINE</STRONG> Underlining 212 <STRONG>A_REVERSE</STRONG> Reverse video 213 <STRONG>A_BLINK</STRONG> Blinking 214 <STRONG>A_DIM</STRONG> Half bright 215 <STRONG>A_BOLD</STRONG> Extra bright or bold 216 <STRONG>A_PROTECT</STRONG> Protected mode 217 <STRONG>A_INVIS</STRONG> Invisible or blank mode 218 <STRONG>A_ALTCHARSET</STRONG> Alternate character set 219 <STRONG>A_ITALIC</STRONG> Italics (non-X/Open extension) 220 <STRONG>A_CHARTEXT</STRONG> Bit-mask to extract a character 221 <STRONG>A_COLOR</STRONG> Bit-mask to extract a color (legacy routines) 222 223 These video attributes are supported by <STRONG>attr_on</STRONG> and related functions 224 (which also support the attributes recognized by <STRONG>attron</STRONG>, etc.): 225 226 <STRONG>Name</STRONG> <STRONG>Description</STRONG> 227 ----------------------------------------------------------------- 228 <STRONG>WA_HORIZONTAL</STRONG> Horizontal highlight 229 <STRONG>WA_LEFT</STRONG> Left highlight 230 <STRONG>WA_LOW</STRONG> Low highlight 231 <STRONG>WA_RIGHT</STRONG> Right highlight 232 <STRONG>WA_TOP</STRONG> Top highlight 233 <STRONG>WA_VERTICAL</STRONG> Vertical highlight 234 235 The return values of many of these routines are not meaningful (they 236 are implemented as macro-expanded assignments and simply return their 237 argument). The SVr4 manual page claims (falsely) that these routines 238 always return <STRONG>1</STRONG>. 239 240 241</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE> 242 All routines return the integer <STRONG>OK</STRONG> on success, or <STRONG>ERR</STRONG> on failure. 243 244 X/Open Curses does not specify any error conditions. 245 246 This implementation 247 248 <STRONG>o</STRONG> returns an error if the window pointer is null. 249 250 <STRONG>o</STRONG> returns an error if the color pair parameter for <STRONG>wcolor_set</STRONG> is 251 outside the range 0..COLOR_PAIRS-1. 252 253 <STRONG>o</STRONG> does not return an error if either of the parameters of <STRONG>wattr_get</STRONG> 254 used for retrieving attribute or color pair values is <STRONG>NULL</STRONG>. 255 256 Functions prefixed with "mv" first perform cursor movement and fail if 257 the position (<EM>y</EM>, <EM>x</EM>) is outside the window boundaries. 258 259 260</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE> 261 These functions may be macros: 262 263 <STRONG>attroff</STRONG>, <STRONG>wattroff</STRONG>, <STRONG>attron</STRONG>, <STRONG>wattron</STRONG>, <STRONG>attrset</STRONG>, <STRONG>wattrset</STRONG>, <STRONG>standend</STRONG> 264 and <STRONG>standout</STRONG>. 265 266 Color pair values can only be OR'd with attributes if the pair number 267 is less than 256. The alternate functions such as <STRONG>color_set</STRONG> can pass a 268 color pair value directly. However, <EM>ncurses</EM> ABI 4 and 5 simply OR this 269 value within the alternate functions. You must use <EM>ncurses</EM> ABI 6 to 270 support more than 256 color pairs. 271 272 273</PRE><H2><a name="h2-EXTENSIONS">EXTENSIONS</a></H2><PRE> 274 This implementation provides the <STRONG>A_ITALIC</STRONG> attribute for terminals which 275 have the <STRONG>enter_italics_mode</STRONG> (<STRONG>sitm</STRONG>) and <STRONG>exit_italics_mode</STRONG> (<STRONG>ritm</STRONG>) 276 capabilities. Italics are not mentioned in X/Open Curses. Unlike the 277 other video attributes, <STRONG>A_ITALIC</STRONG> is unrelated to the <STRONG>set_attributes</STRONG> 278 capabilities. This implementation makes the assumption that 279 <STRONG>exit_attribute_mode</STRONG> may also reset italics. 280 281 Each of the functions added by XSI Curses has a parameter <EM>opts</EM>, which 282 X/Open Curses still (after more than twenty years) documents as 283 reserved for future use, saying that it should be <STRONG>NULL</STRONG>. This 284 implementation uses that parameter in ABI 6 for the functions which 285 have a color pair parameter to support <EM>extended</EM> <EM>color</EM> <EM>pairs</EM>: 286 287 <STRONG>o</STRONG> For functions which modify the color, e.g., <STRONG>wattr_set</STRONG> and <STRONG>wattr_on</STRONG>, 288 if <EM>opts</EM> is set it is treated as a pointer to <STRONG>int</STRONG>, and used to set 289 the color pair instead of the <STRONG>short</STRONG> <EM>pair</EM> parameter. 290 291 <STRONG>o</STRONG> For functions which retrieve the color, e.g., <STRONG>wattr_get</STRONG>, if <EM>opts</EM> is 292 set it is treated as a pointer to <STRONG>int</STRONG>, and used to retrieve the 293 color pair as an <STRONG>int</STRONG> value, in addition to retrieving it via the 294 standard pointer to <STRONG>short</STRONG> parameter. 295 296 <STRONG>o</STRONG> For functions which turn attributes off, e.g., <STRONG>wattr_off</STRONG>, the <EM>opts</EM> 297 parameter is ignored except except to check that it is <STRONG>NULL</STRONG>. 298 299 300</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE> 301 These functions are described in X/Open Curses, Issue 4. The standard 302 defined the dedicated type for highlights, <STRONG>attr_t</STRONG>, which was not 303 defined in SVr4 curses. The functions taking <STRONG>attr_t</STRONG> arguments were not 304 supported under SVr4. 305 306 Very old versions of this library did not force an update of the screen 307 when changing the attributes. Use <STRONG>touchwin</STRONG> to force the screen to 308 match the updated attributes. 309 310 X/Open Curses states that whether the traditional functions 311 <STRONG>attron</STRONG>/<STRONG>attroff</STRONG>/<STRONG>attrset</STRONG> can manipulate attributes other than <STRONG>A_BLINK</STRONG>, 312 <STRONG>A_BOLD</STRONG>, <STRONG>A_DIM</STRONG>, <STRONG>A_REVERSE</STRONG>, <STRONG>A_STANDOUT</STRONG>, or <STRONG>A_UNDERLINE</STRONG> is "unspecified". 313 Under this implementation as well as SVr4 curses, these functions 314 correctly manipulate all other highlights (specifically, <STRONG>A_ALTCHARSET</STRONG>, 315 <STRONG>A_PROTECT</STRONG>, and <STRONG>A_INVIS</STRONG>). 316 317 X/Open Curses added these entry points: 318 319 <STRONG>attr_get</STRONG>, <STRONG>attr_on</STRONG>, <STRONG>attr_off</STRONG>, <STRONG>attr_set</STRONG>, <STRONG>wattr_on</STRONG>, <STRONG>wattr_off</STRONG>, 320 <STRONG>wattr_get</STRONG>, <STRONG>wattr_set</STRONG> 321 322 The new functions are intended to work with a new series of highlight 323 macros prefixed with <STRONG>WA_</STRONG>. The older macros have direct counterparts in 324 the newer set of names: 325 326 <STRONG>Name</STRONG> <STRONG>Description</STRONG> 327 ----------------------------------------------------------------- 328 <STRONG>WA_NORMAL</STRONG> Normal display (no highlight) 329 <STRONG>WA_STANDOUT</STRONG> Best highlighting mode of the terminal 330 <STRONG>WA_UNDERLINE</STRONG> Underlining 331 <STRONG>WA_REVERSE</STRONG> Reverse video 332 <STRONG>WA_BLINK</STRONG> Blinking 333 <STRONG>WA_DIM</STRONG> Half bright 334 <STRONG>WA_BOLD</STRONG> Extra bright or bold 335 336 <STRONG>WA_ALTCHARSET</STRONG> Alternate character set 337 338 X/Open Curses does not assign values to these symbols, nor does it 339 state whether or not they are related to the similarly-named A_NORMAL, 340 etc.: 341 342 <STRONG>o</STRONG> X/Open Curses specifies that each pair of corresponding <STRONG>A_</STRONG> and 343 <STRONG>WA_</STRONG>-using functions operates on the same current-highlight 344 information. 345 346 <STRONG>o</STRONG> However, in some implementations, those symbols have unrelated 347 values. 348 349 For example, the Solaris <EM>xpg4</EM> (X/Open) curses declares <STRONG>attr_t</STRONG> to be 350 an unsigned short integer (16-bits), while <STRONG>chtype</STRONG> is a unsigned 351 integer (32-bits). The <STRONG>WA_</STRONG> symbols in this case are different from 352 the <STRONG>A_</STRONG> symbols because they are used for a smaller datatype which 353 does not represent <STRONG>A_CHARTEXT</STRONG> or <STRONG>A_COLOR</STRONG>. 354 355 In this implementation (as in many others), the values happen to be 356 the same because it simplifies copying information between <STRONG>chtype</STRONG> 357 and <STRONG>cchar_t</STRONG> variables. 358 359 <STRONG>o</STRONG> Because <EM>ncurses</EM>'s <STRONG>attr_t</STRONG> can hold a color pair (in the <STRONG>A_COLOR</STRONG> 360 field), a call to <STRONG>wattr_on</STRONG>, <STRONG>wattr_off</STRONG>, or <STRONG>wattr_set</STRONG> may alter the 361 window's color. If the color pair information in the attribute 362 parameter is zero, no change is made to the window's color. 363 364 This is consistent with SVr4 curses; X/Open Curses does not specify 365 this. 366 367 The X/Open Curses extended conformance level adds new highlights 368 <STRONG>A_HORIZONTAL</STRONG>, <STRONG>A_LEFT</STRONG>, <STRONG>A_LOW</STRONG>, <STRONG>A_RIGHT</STRONG>, <STRONG>A_TOP</STRONG>, <STRONG>A_VERTICAL</STRONG> (and 369 corresponding <STRONG>WA_</STRONG> macros for each). As of August 2013, no known 370 terminal provides these highlights (i.e., via the <STRONG>sgr1</STRONG> capability). 371 372 373</PRE><H2><a name="h2-HISTORY">HISTORY</a></H2><PRE> 374 X/Open Curses is largely based on SVr4 curses, adding support for 375 "wide-characters" (not specific to Unicode). Some of the X/Open 376 differences from SVr4 curses address the way video attributes can be 377 applied to wide-characters. But aside from that, <STRONG>attrset</STRONG> and <STRONG>attr_set</STRONG> 378 are similar. SVr4 curses provided the basic features for manipulating 379 video attributes. However, earlier versions of curses provided a part 380 of these features. 381 382 As seen in 2.8BSD, curses assumed 7-bit characters, using the eighth 383 bit of a byte to represent the <EM>standout</EM> feature (often implemented as 384 bold and/or reverse video). The BSD curses library provided functions 385 <STRONG>standout</STRONG> and <STRONG>standend</STRONG> which were carried along into X/Open Curses due 386 to their pervasive use in legacy applications. 387 388 Some terminals in the 1980s could support a variety of video 389 attributes, although the BSD curses library could do nothing with 390 those. System V (1983) provided an improved curses library. It 391 defined the <STRONG>A_</STRONG> symbols for use by applications to manipulate the other 392 attributes. There are few useful references for the chronology. 393 394 Goodheart's book <EM>UNIX</EM> <EM>Curses</EM> <EM>Explained</EM> (1991) describes SVr3 (1987), 395 commenting on several functions: 396 397 <STRONG>o</STRONG> the <STRONG>attron</STRONG>, <STRONG>attroff</STRONG>, <STRONG>attrset</STRONG> functions (and most of the functions 398 found in SVr4 but not in BSD curses) were introduced by System V, 399 400 <STRONG>o</STRONG> the alternate character set feature with <STRONG>A_ALTCHARSET</STRONG> was added in 401 SVr2 and improved in SVr3 (by adding <STRONG>acs_map[]</STRONG>), 402 403 <STRONG>o</STRONG> <STRONG>start_color</STRONG> and related color-functions were introduced by System 404 V.3.2, 405 406 <STRONG>o</STRONG> pads, soft-keys were added in SVr3, and 407 408 Goodheart did not mention the background character or the <STRONG>cchar_t</STRONG> type. 409 Those are respectively SVr4 and X/Open features. He did mention the <STRONG>A_</STRONG> 410 constants, but did not indicate their values. Those were not the same 411 in different systems, even for those marked as System V. 412 413 Different Unix systems used different sizes for the bit-fields in 414 <STRONG>chtype</STRONG> for <EM>characters</EM> and <EM>colors</EM>, and took into account the different 415 integer sizes (32-bit versus 64-bit). 416 417 This table showing the number of bits for <STRONG>A_COLOR</STRONG> and <STRONG>A_CHARTEXT</STRONG> was 418 gleaned from the curses header files for various operating systems and 419 architectures. The inferred architecture and notes reflect the format 420 and size of the defined constants as well as clues such as the 421 alternate character set implementation. A 32-bit library can be used 422 on a 64-bit system, but not necessarily the reverse. 423 424 <STRONG>Bits</STRONG> 425 <STRONG>Year</STRONG> <STRONG>System</STRONG> <STRONG>Arch</STRONG> <STRONG>Color</STRONG> <STRONG>Char</STRONG> <STRONG>Notes</STRONG> 426 ------------------------------------------------------------------------ 427 1992 Solaris 5.2 32 6 17 SVr4 <EM>curses</EM> 428 1992 HP-UX 9 32 no 8 SVr2 <EM>curses</EM> 429 1992 AIX 3.2 32 no 23 SVr2 <EM>curses</EM> 430 1994 OSF/1 r3 32 no 23 SVr2 <EM>curses</EM> 431 1995 HP-UX 10.00 32 6 16 SVr3 <EM>curses</EM><STRONG>_</STRONG><EM>colr</EM> 432 1995 HP-UX 10.00 32 6 8 SVr4, X/Open <EM>curses</EM> 433 1995 Solaris 5.4 32/64 7 16 X/Open <EM>curses</EM> 434 1996 AIX 4.2 32 7 16 X/Open <EM>curses</EM> 435 1996 OSF/1 r4 32 6 16 X/Open <EM>curses</EM> 436 1997 HP-UX 11.00 32 6 8 X/Open <EM>curses</EM> 437 2000 U/Win 32/64 7/31 16 uses <EM>chtype</EM> 438 439 Notes: 440 441 Regarding HP-UX, 442 443 <STRONG>o</STRONG> HP-UX 10.20 (1996) added support for 64-bit PA-RISC processors 444 in 1996. 445 446 <STRONG>o</STRONG> HP-UX 10.30 (1997) marked "curses_colr" obsolete. That version 447 of curses was dropped with HP-UX 11.30 in 2006. 448 449 Regarding OSF/1 (and Tru64), 450 451 <STRONG>o</STRONG> These used 64-bit hardware. Like <EM>ncurses</EM>, the OSF/1 curses 452 interface is not customized for 32-bit and 64-bit versions. 453 454 <STRONG>o</STRONG> Unlike other systems which evolved from AT&T code, OSF/1 455 provided a new implementation for X/Open curses. 456 457 Regarding Solaris, 458 459 <STRONG>o</STRONG> The initial release of Solaris was in 1992. 460 461 <STRONG>o</STRONG> The <EM>xpg4</EM> (X/Open) curses was developed by MKS from 1990 to 1995. 462 Sun's copyright began in 1996. 463 464 <STRONG>o</STRONG> Sun updated the X/Open curses interface after 64-bit support was 465 introduced in 1997, but did not modify the SVr4 curses 466 interface. 467 468 Regarding U/Win, 469 470 <STRONG>o</STRONG> Development of the curses library began in 1991, stopped in 471 2000. 472 473 <STRONG>o</STRONG> Color support was added in 1998. 474 475 <STRONG>o</STRONG> The library uses only <STRONG>chtype</STRONG> (no <STRONG>cchar_t</STRONG>). 476 477 Once X/Open curses was adopted in the mid-1990s, the constraint of a 478 32-bit interface with many colors and wide-characters for <STRONG>chtype</STRONG> became 479 a moot point. The <STRONG>cchar_t</STRONG> structure (whose size and members are not 480 specified in X/Open Curses) could be extended as needed. 481 482 Other interfaces are rarely used now: 483 484 <STRONG>o</STRONG> BSD curses was improved slightly in 1993/1994 using Keith Bostic's 485 modification to make the library 8-bit clean for <STRONG>nvi(1)</STRONG>. He moved 486 <EM>standout</EM> attribute to a structure member. 487 488 The resulting 4.4BSD curses was replaced by <EM>ncurses</EM> over the next 489 ten years. 490 491 <STRONG>o</STRONG> U/Win is rarely used now. 492 493 494</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE> 495 <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>, 496 <STRONG><A HREF="curs_printw.3x.html">curs_printw(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG> 497 498 499 500ncurses 6.5 2024-04-27 <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG> 501</PRE> 502<div class="nav"> 503<ul> 504<li><a href="#h2-NAME">NAME</a></li> 505<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li> 506<li><a href="#h2-DESCRIPTION">DESCRIPTION</a> 507<ul> 508<li><a href="#h3-Window-Attributes">Window Attributes</a></li> 509<li><a href="#h3-Legacy-Window-Attributes">Legacy Window Attributes</a></li> 510<li><a href="#h3-Change-Character-Rendition">Change Character Rendition</a></li> 511<li><a href="#h3-Change-Window-Color">Change Window Color</a></li> 512<li><a href="#h3-Standout">Standout</a></li> 513<li><a href="#h3-Video-Attributes">Video Attributes</a></li> 514</ul> 515</li> 516<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li> 517<li><a href="#h2-NOTES">NOTES</a></li> 518<li><a href="#h2-EXTENSIONS">EXTENSIONS</a></li> 519<li><a href="#h2-PORTABILITY">PORTABILITY</a></li> 520<li><a href="#h2-HISTORY">HISTORY</a></li> 521<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li> 522</ul> 523</div> 524</BODY> 525</HTML> 526