NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | PORTABILITY | SEE ALSO | COLOPHON

curs_addch(3X)                                                curs_addch(3X)

NAME         top

       addch, waddch, mvaddch, mvwaddch, echochar, wechochar - add a charac‐
       ter (with attributes) to a curses window, then advance the cursor

SYNOPSIS         top

       #include <curses.h>

       int addch(const chtype ch);
       int waddch(WINDOW *win, const chtype ch);
       int mvaddch(int y, int x, const chtype ch);
       int mvwaddch(WINDOW *win, int y, int x, const chtype ch);
       int echochar(const chtype ch);
       int wechochar(WINDOW *win, const chtype ch);

DESCRIPTION         top

   Adding characters
       The addch, waddch, mvaddch and mvwaddch routines put the character ch
       into the given window at its current window position, which is then
       advanced.  They are analogous to putchar(3) in stdio(3).  If the
       advance is at the right margin:

       ·   The cursor automatically wraps to the beginning of the next line.

       ·   At the bottom of the current scrolling region, and if scrollok is
           enabled, the scrolling region is scrolled up one line.

       ·   If scrollok is not enabled, writing a character at the lower
           right margin succeeds.  However, an error is returned because it
           is not possible to wrap to a new line

       If ch is a tab, newline, carriage return or backspace, the cursor is
       moved appropriately within the window:

       ·   Backspace moves the cursor one character left; at the left edge
           of a window it does nothing.

       ·   Carriage return moves the cursor to the window left margin on the
           current line.

       ·   Newline does a clrtoeol, then moves the cursor to the window left
           margin on the next line, scrolling the window if on the last
           line.

       ·   Tabs are considered to be at every eighth column.  The tab
           interval may be altered by setting the TABSIZE variable.

       If ch is any other control character, it is drawn in ^X notation.
       Calling winch after adding a control character does not return the
       character itself, but instead returns the ^-representation of the
       control character.

       Video attributes can be combined with a character argument passed to
       addch or related functions by logical-ORing them into the character.
       (Thus, text, including attributes, can be copied from one place to
       another using inch(3X) and addch.)  See the curs_attr(3X) page for
       values of predefined video attribute constants that can be usefully
       OR'ed into characters.

   Echoing characters
       The echochar and wechochar routines are equivalent to a call to addch
       followed by a call to refresh(3X), or a call to waddch followed by a
       call to wrefresh.  The knowledge that only a single character is
       being output is used and, for non-control characters, a considerable
       performance gain may be seen by using these routines instead of their
       equivalents.

   Line Graphics
       The following variables may be used to add line drawing characters to
       the screen with routines of the addch family.  The default character
       listed below is used if the acsc capability does not define a
       terminal-specific replacement for it, or if the terminal and locale
       configuration requires Unicode but the library is unable to use
       Unicode.

       The names are taken from VT100 nomenclature.

       ACS            ACS       acsc   Glyph
       Name           Default   char   Name
       ─────────────────────────────────────────────────────────
       ACS_BLOCK      #         0      solid square block
       ACS_BOARD      #         h      board of squares
       ACS_BTEE       +         v      bottom tee
       ACS_BULLET     o         ~      bullet
       ACS_CKBOARD    :         a      checker board (stipple)
       ACS_DARROW     v         .      arrow pointing down
       ACS_DEGREE     '         f      degree symbol
       ACS_DIAMOND    +         `      diamond
       ACS_GEQUAL     >         >      greater-than-or-equal-to
       ACS_HLINE      -         q      horizontal line
       ACS_LANTERN    #         i      lantern symbol
       ACS_LARROW     <         ,      arrow pointing left
       ACS_LEQUAL     <         y      less-than-or-equal-to
       ACS_LLCORNER   +         m      lower left-hand corner
       ACS_LRCORNER   +         j      lower right-hand corner
       ACS_LTEE       +         t      left tee
       ACS_NEQUAL     !         |      not-equal
       ACS_PI         *         {      greek pi
       ACS_PLMINUS    #         g      plus/minus
       ACS_PLUS       +         n      plus
       ACS_RARROW     >         +      arrow pointing right
       ACS_RTEE       +         u      right tee
       ACS_S1         -         o      scan line 1
       ACS_S3         -         p      scan line 3
       ACS_S7         -         r      scan line 7
       ACS_S9         _         s      scan line 9
       ACS_STERLING   f         }      pound-sterling symbol
       ACS_TTEE       +         w      top tee
       ACS_UARROW     ^         -      arrow pointing up
       ACS_ULCORNER   +         l      upper left-hand corner
       ACS_URCORNER   +         k      upper right-hand corner
       ACS_VLINE      |         x      vertical line

RETURN VALUE         top

       All routines return the integer ERR upon failure and OK on success
       (the SVr4 manuals specify only “an integer value other than ERR”)
       upon successful completion, unless otherwise noted in the preceding
       routine descriptions.

       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         top

       Note that addch, mvaddch, mvwaddch, and echochar may be macros.

PORTABILITY         top

       All these functions are described in the XSI Curses standard, Issue
       4.  The defaults specified for forms-drawing characters apply in the
       POSIX locale.

       X/Open Curses states that the ACS_ definitions are char constants.
       For the wide-character implementation (see curs_add_wch), there are
       analogous WACS_ definitions which are cchar_t constants.

       Some ACS symbols (ACS_S3, ACS_S7, ACS_LEQUAL, ACS_GEQUAL, ACS_PI,
       ACS_NEQUAL, ACS_STERLING) were not documented in any publicly
       released System V.  However, many publicly available terminfos
       include acsc strings in which their key characters (pryz{|}) are
       embedded, and a second-hand list of their character descriptions has
       come to light.  The ACS-prefixed names for them were invented for
       ncurses(3X).

       The displayed values for the ACS_ and WACS_ constants depend on

       ·   the library configuration, i.e., ncurses versus ncursesw, where
           the latter is capable of displaying Unicode while the former is
           not, and

       ·   whether the locale uses UTF-8 encoding.

       In certain cases, the terminal is unable to display line-drawing
       characters except by using UTF-8 (see the discussion of
       NCURSES_NO_UTF8_ACS in ncurses(3X)).

       The TABSIZE variable is implemented in some versions of curses, but
       is not part of X/Open curses.

       If ch is a carriage return, the cursor is moved to the beginning of
       the current row of the window.  This is true of other
       implementations, but is not documented.

SEE ALSO         top

       curses(3X), curs_attr(3X), curs_clear(3X), curs_inch(3X),
       curs_outopts(3X), curs_refresh(3X), curs_variables(3X), putc(3).

       Comparable functions in the wide-character (ncursesw) library are
       described in curs_add_wch(3X).

COLOPHON         top

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                                                              curs_addch(3X)