curs_add_wch

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
NOTES
PORTABILITY
SEE ALSO

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 complex character wch into the given window at its current position, which is then advanced. These functions perform wrapping and special-character 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 cursor 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 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 functionally 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 performance 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 correspond 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 VALUE

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 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 double-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.