add_wch, wadd_wch, mvadd_wch, mvwadd_wch, echo_wchar, wecho_wchar - add
a complex character and rendition to a curses window, then advance the
int add_wch( const cchar_t *wch );
int wadd_wch( WINDOW *win, const cchar_t *wch );
int mvadd_wch( int y, int x, const cchar_t *wch );
int mvwadd_wch( WINDOW *win, int y, int x, const cchar_t *wch );
int echo_wchar( const cchar_t *wch );
int wecho_wchar( WINDOW *win, const cchar_t *wch );
The add_wch, wadd_wch, mvadd_wch, and mvwadd_wch functions put the com-
plex character wch into the given window at its current position, which
is then advanced. These functions perform wrapping and special-charac-
ter processing as follows:
- If wch refers to a spacing character, then any previous character
at that location is removed. A new character specified by wch is
placed at that location with rendition specified by wch. The cur-
sor then advances to the next spacing character on the screen.
- 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(3X) were called.
The echo_wchar function is functionally equivalent to a call to add_wch
followed by a call to refresh. Similarly, the wecho_wchar is function-
ally equivalent to a call to wadd_wch followed by a call to wrefresh.
The knowledge that only a single character is being output is taken
into consideration and, for non-control characters, a considerable per-
formance gain might be seen by using the *echo* functions instead of
All routines return the integer ERR upon failure and OK on success.
Note that add_wch, mvadd_wch, mvwadd_wch, and echo_wchar may be macros.
All these functions are described in the XSI Curses standard, Issue 4.
The defaults specified for forms-drawing characters apply in the POSIX
XSI documents constants beginning with WACS_ which are used for line-
drawing. Those are not currently implemented in ncurses.
curses(3X), curs_attr_get(3X), curs_clear(3X), curs_outopts(3X),