mvaddch(3x) — Linux manual page


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

       ·   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

   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

       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.

       If it is not possible to add a complete character, an error is

       ·   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 an error is detected when converting a multibyte character to
           a sequence of bytes, or if it is not possible to add all of the
           resulting bytes in the window, an error is returned.

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.

   ACS Symbols
       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
       implementations are problematic:

       ·   Some implementations define the ACS symbols to a constant (such
           as Solaris), while others define those to entries in an array.

           This implementation uses an array acs_map, as done in SVr4
           curses.  NetBSD also uses an array, actually named _acs_char,
           with a #define for compatibility.

       ·   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 (issues 2 through 7) has a typographical error for
           the ACS_LANTERN symbol, equating its “VT100+ Character” to I
           (capital I), while the header files for SVr4 curses and the
           various implementations use i (lowercase).

           None of the terminal descriptions on Unix platforms use
           uppercase-I, except for Solaris (i.e., screen's terminal
           description, apparently based on the X/Open documentation around
           1995).  On the other hand, the terminal description gs6300 (AT&T
           PC6300 with EMOTS Terminal Emulator) uses lowercase-i.

       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

       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)).

   Character Set
       X/Open Curses assumes that the parameter passed to waddch contains a
       single character.  As discussed in curs_attr(3X), that character may
       have been more than eight bits in an SVr3 or SVr4 implementation, but
       in the X/Open Curses model, the details are not given.  The important
       distinction between SVr4 curses and X/Open Curses is that the non-
       character information (attributes and color) was separated from the
       character information which is packed in a chtype to pass to waddch.

       In this implementation, chtype holds an eight-bit character.  But
       ncurses allows multibyte characters to be passed in a succession of
       calls to waddch.  The other implementations do not do this; a call to
       waddch passes exactly one character which may be rendered as one or
       more cells on the screen depending on whether it is printable.

       Depending on the locale settings, ncurses will inspect the byte
       passed in each call to waddch, and check if the latest call will
       continue a multibyte sequence.  When a character is complete, ncurses
       displays the character and moves to the next position in the screen.

       If the calling application interrupts the succession of bytes in a
       multibyte character by moving the current location (e.g., using
       wmove), ncurses discards the partially built character, starting over

       For portability to other implementations, do not rely upon this

       ·   check if a character can be represented as a single byte in the
           current locale before attempting call waddch, and

       ·   call wadd_wch for characters which cannot be handled by waddch.

       The TABSIZE variable is implemented in SVr4 and other versions of
       curses, but is not part of X/Open curses (see curs_variables(3X) for
       more details).

       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

       This page is part of the ncurses (new curses) project.  Information
       about the project can be found at 
       ⟨⟩.  If you have a
       bug report for this manual page, send it to  This page was obtained from the
       project's upstream Git mirror of the CVS repository
       ⟨git://⟩ on 2020-09-18.  (At that
       time, the date of the most recent commit that was found in the repos‐
       itory was 2020-08-17.)  If you discover any rendering problems in
       this HTML version of the page, or you believe there is a better or
       more up-to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not part
       of the original manual page), send a mail to