curs_add_wch(3X)curs_add_wch(3X)NAME
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
cursor
SYNOPSIS
#include <curses.h>
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 );
DESCRIPTION
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 spec‐
ified 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.
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
their equivalents.
Line Graphics
Like addch(3X), addch_wch accepts symbols which make it simple to draw
lines and other frequently used special characters. These symbols cor‐
respond to the same VT100 line-drawing set as addch(3X).
The wide-character configuration of ncurses also defines symbols for
thick- and double-lines:
RETURN VALUES
All routines return the integer ERR upon failure and OK on success.
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.
NOTES
Note that add_wch, mvadd_wch, mvwadd_wch, and echo_wchar may be macros.
PORTABILITY
All of these functions are described in the XSI Curses standard, Issue
4. The defaults specified for line-drawing characters apply in the
POSIX locale.
X/Open Curses makes it clear that the WACS_ symbols should be defined
as a pointer to cchar_t data, e.g., in the discussion of border_set. A
few implementations are problematic:
· NetBSD curses defines the symbols as a wchar_t within a cchar_t.
· HPUX curses equates some of the ACS_ symbols to the analogous WACS_
symbols as if the ACS_ symbols were wide characters. The misde‐
fined symbols are the arrows and other symbols which are not used
for line-drawing.
X/Open Curses does not define symbols for thick- or double-lines. SVr4
curses implementations defined their line-drawing symbols in terms of
intermediate symbols. This implementation extends those symbols, pro‐
viding new definitions which are not in the SVr4 implementations.
SEE ALSOcurses(3X), curs_addch(3X), curs_attr(3X), curs_clear(3X), curs_out‐
opts(3X), curs_refresh(3X), putwc(3)curs_add_wch(3X)
