The add_wch, wadd_wch, mvadd_wch, and mvwadd_wch functions
put the complex character wch into the given window at its
current position, which is then advanced. These functions
perform wrapping and special-character processing as fol-
lows:
- - If wch refers to a spacing character, then any previ-
- ous character at that location is removed. A new
- character specified by wch is placed at that location
- with rendition specified by wch. The cursor then
- advances to the next spacing character on the screen.
+ o If wch refers to a spacing character, then any previ-
+ ous character at that location is removed. A new
+ character specified by wch is placed at that location
+ with rendition specified by wch. The cursor then
+ advances to the next spacing character on the screen.
- - If wch refers to a non-spacing character, all previ-
- ous characters at that location are preserved. The
- non-spacing characters of wch are added to the spac-
- ing complex character, and the rendition specified by
- wch is ignored.
+ o If wch refers to a non-spacing character, all previous
+ characters at that location are preserved. The non-
+ spacing characters of wch are added to the spacing
+ complex character, and the rendition specified by wch
+ is ignored.
- - If the character part of wch is a tab, newline,
- backspace or other control character, the window is
- updated and the cursor moves as if addch were called.
+ o If the character part of wch is a tab, newline,
+ backspace or other control character, the window is
+ updated and the cursor moves as if addch were called.
The echo_wchar function is functionally equivalent to a
call to add_wch followed by a call to refresh. Similarly,
@@ -100,41 +101,143 @@
All routines return the integer ERR upon failure and OK on
success.
+ Functions with a "mv" prefix first perform a cursor move-
+ ment using wmove, and return an error if the position is
+ outside the window, or if the window pointer is null.
+
Note that add_wch, mvadd_wch, mvwadd_wch, and echo_wchar
may be macros.
-
PORTABILITY
- All these functions are described in the XSI Curses stan-
- dard, Issue 4. The defaults specified for forms-drawing
- characters apply in the POSIX locale.
+
+ All of these functions are described in the XSI Curses
+ standard, Issue 4. The defaults specified for line-draw-
+ ing characters apply in the POSIX locale.
- XSI documents constants beginning with WACS_ which are
- used for line-drawing. Those are not currently imple-
- mented in ncurses.
+ X/Open Curses makes it clear that the WACS_ symbols should
+ be defined as a pointer to cchar_t data, e.g., in the dis-
+ cussion of border_set. A few implementations are problem-
+ atic:
+
+ o NetBSD curses defines the symbols as a wchar_t within
+ a cchar_t.
+
+ o HPUX curses equates some of the ACS_ symbols to the
+ analogous WACS_ symbols as if the ACS_ symbols were
+ wide characters. The misdefined symbols are the
+ arrows and other symbols which are not used for line-
+ drawing.
+
+ X/Open Curses does not define symbols for thick- or dou-
+ ble-lines. SVr4 curses implementations defined their
+ line-drawing symbols in terms of intermediate symbols.
+ This implementation extends those symbols, providing new
+ definitions which are not in the SVr4 implementations.