-</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_at-</STRONG>
- <STRONG>tribute_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.
-
-