gnu Man Page: curs_add

Man Pages

Back to Software Index BORDER=0

Manpage Top Level

curs_add_wch(3X) manual page Table of Contents

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

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) .

Name Unicode Default Description

WACS_BLOCK 0x25ae # solid square block

WACS_BOARD

WACS_BTEE

WACS_BULLET

WACS_CKBOARD

WACS_DARROW

WACS_DEGREE

WACS_DIAMOND

WACS_GEQUAL

WACS_HLINE

WACS_LANTERN

WACS_LARROW

WACS_LEQUAL

WACS_LLCORNER

WACS_LRCORNER

WACS_LTEE

WACS_NEQUAL

WACS_PI

WACS_PLMINUS

WACS_PLUS

WACS_RARROW

WACS_RTEE

WACS_S1

WACS_S3

WACS_S7

WACS_S9

WACS_STERLING

WACS_TTEE

WACS_UARROW

WACS_ULCORNER

WACS_URCORNER

WACS_VLINE

The wide-character configuration of ncurses also defines symbols for thick- and double-lines:

Name Unicode Default Description

WACS_T_ULCORNER 0x250f + thick upper left corner

WACS_T_LLCORNER

WACS_T_URCORNER

WACS_T_LRCORNER

WACS_T_LTEE

WACS_T_RTEE

WACS_T_BTEE

WACS_T_TTEE

WACS_T_HLINE

WACS_T_VLINE

WACS_T_PLUS

WACS_D_ULCORNER

WACS_D_LLCORNER

WACS_D_URCORNER

WACS_D_LRCORNER

WACS_D_RTEE

WACS_D_LTEE

WACS_D_BTEE

WACS_D_TTEE

WACS_D_HLINE

WACS_D_VLINE

WACS_D_PLUS

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 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.