Other Alias
add_wch, wadd_wch, mvadd_wch, mvwadd_wch, wecho_wcharSYNOPSIS
#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
add_wch
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.
echo_wchar
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_BOARD | 0x2592 | # | board of squares |
| WACS_BTEE | 0x2534 | + | bottom tee |
| WACS_BULLET | 0x00b7 | o | bullet |
| WACS_CKBOARD | 0x2592 | : | checker board (stipple) |
| WACS_DARROW | 0x2193 | v | arrow pointing down |
| WACS_DEGREE | 0x00b0 | ' | degree symbol |
| WACS_DIAMOND | 0x25c6 | + | diamond |
| WACS_GEQUAL | 0x2265 | > | greater-than-or-equal-to |
| WACS_HLINE | 0x2500 | - | horizontal line |
| WACS_LANTERN | 0x2603 | # | lantern symbol |
| WACS_LARROW | 0x2190 | < | arrow pointing left |
| WACS_LEQUAL | 0x2264 | < | less-than-or-equal-to |
| WACS_LLCORNER | 0x2514 | + | lower left-hand corner |
| WACS_LRCORNER | 0x2518 | + | lower right-hand corner |
| WACS_LTEE | 0x2524 | + | left tee |
| WACS_NEQUAL | 0x2260 | ! | not-equal |
| WACS_PI | 0x03c0 | * | greek pi |
| WACS_PLMINUS | 0x00b1 | # | plus/minus |
| WACS_PLUS | 0x253c | + | plus |
| WACS_RARROW | 0x2192 | > | arrow pointing right |
| WACS_RTEE | 0x251c | + | right tee |
| WACS_S1 | 0x23ba | - | scan line 1 |
| WACS_S3 | 0x23bb | - | scan line 3 |
| WACS_S7 | 0x23bc | - | scan line 7 |
| WACS_S9 | 0x23bd | _ | scan line 9 |
| WACS_STERLING | 0x00a3 | f | pound-sterling symbol |
| WACS_TTEE | 0x252c | + | top tee |
| WACS_UARROW | 0x2191 | ^ | arrow pointing up |
| WACS_ULCORNER | 0x250c | + | upper left-hand corner |
| WACS_URCORNER | 0x2510 | + | upper right-hand corner |
| WACS_VLINE | 0x2502 | | | vertical line |
The wide-character configuration of ncurses also defines symbols for thick- and double-lines:
| Name | Unicode | Default | Description |
| WACS_T_LLCORNER | 0x2517 | + | thick lower left corner |
| WACS_T_URCORNER | 0x2513 | + | thick upper right corner |
| WACS_T_LRCORNER | 0x251b | + | thick lower right corner |
| WACS_T_LTEE | 0x252b | + | thick tee pointing right |
| WACS_T_RTEE | 0x2523 | + | thick tee pointing left |
| WACS_T_BTEE | 0x253b | + | thick tee pointing up |
| WACS_T_TTEE | 0x2533 | + | thick tee pointing down |
| WACS_T_HLINE | 0x2501 | - | thick horizontal line |
| WACS_T_VLINE | 0x2503 | | | thick vertical line |
| WACS_T_PLUS | 0x254b | + | thick large plus or crossover |
| WACS_D_ULCORNER | 0x2554 | + | double upper left corner |
| WACS_D_LLCORNER | 0x255a | + | double lower left corner |
| WACS_D_URCORNER | 0x2557 | + | double upper right corner |
| WACS_D_LRCORNER | 0x255d | + | double lower right corner |
| WACS_D_RTEE | 0x2563 | + | double tee pointing left |
| WACS_D_LTEE | 0x2560 | + | double tee pointing right |
| WACS_D_BTEE | 0x2569 | + | double tee pointing up |
| WACS_D_TTEE | 0x2566 | + | double tee pointing down |
| WACS_D_HLINE | 0x2550 | - | double horizontal line |
| WACS_D_VLINE | 0x2551 | | | double vertical line |
| WACS_D_PLUS | 0x256c | + | double large plus or crossover |
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.