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The routine attrset sets the current attributes of the given window to attrs. The routine attroff turns off the named attributes without turning any other attributes on or off. The routine attron turns on the named attributes without affecting any others. 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.
The attrset and related routines do not affect the attributes used when erasing portions of the window. See curs_bkgd(3X) for functions which modify the attributes used for erasing and clearing.
The routine color_set sets the current color of the given window to the foreground/background combination described by the color_pair_number. The parameter opts is reserved for future use, applications must supply a null pointer.
The routine wattr_get returns the current attribute and color pair for the given window; attr_get returns the current attribute and color pair for stdscr. The remaining attr_* functions operate exactly like the corresponding attr* functions, except that they take arguments of type attr_t rather than int.
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 argument is a color-pair index (as in the first argument of init_pair, see curs_color(3X)). The opts argument is not presently used, but is reserved for the future (leave it NULL).
Name Description A_STANDOUT Best highlighting mode of the terminal. A_UNDERLINE Underlining A_REVERSE Reverse video A_BLINK Blinking A_DIM Half bright A_BOLD Extra bright or bold A_PROTECT Protected mode A_INVIS Invisible or blank mode A_ALTCHARSET Alternate character set A_ITALIC Italics (non-X/Open extension) A_CHARTEXT Bit-mask to extract a character COLOR_PAIR(n) Color-pair number n
These video attributes are supported by attr_on and related functions (which also support the attributes recognized by attron, etc.):
Name Description WA_LEFT Left highlight WA_LOW Low highlight WA_RIGHT Right highlight WA_TOP Top highlight WA_VERTICAL Vertical highlight
The following macro is the reverse of COLOR_PAIR(n):
PAIR_NUMBER(attrs) Returns the pair number associated
with the COLOR_PAIR(n) attribute.
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.
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 support more than 256 color pairs.
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 correctly manipulate all other highlights (specifically, A_ALTCHARSET, A_PROTECT, and A_INVIS).
This implementation provides the A_ITALIC attribute for terminals which 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, I_ITALIC is unrelated to the set_attributes capabilities. This implementation makes the assumption that exit_attribute_mode may also reset italics.
XSI Curses added the new entry points, attr_get, attr_on, attr_off, attr_set, wattr_on, wattr_off, wattr_get, wattr_set. These 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:
Name Description WA_STANDOUT Best highlighting mode of the terminal. WA_UNDERLINE Underlining WA_REVERSE Reverse video WA_BLINK Blinking WA_DIM Half bright WA_BOLD Extra bright or bold WA_ALTCHARSET Alternate character set
Older versions of this library did not force an update of the screen when changing the attributes. Use touchwin to force the screen to match the updated attributes.
The XSI curses standard specifies that each pair of corresponding A_ and WA_-using functions operates on the same current-highlight information.
The XSI standard 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 returns an error if the window pointer is null. The wcolor_set function returns an error if the color pair parameter is outside the range 0..COLOR_PAIRS-1. This implementation also provides getattrs for compatibility with older versions of curses.
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.
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|“||… one of the main causes of the fall of the Roman Empire was that, lacking zero, they had no way to indicate successful termination of their C programs.||”|
|— Robert Firth|