# curs_addch 3x

    curs_addch(3x)                                           curs_addch(3x)

## NAME

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

## SYNOPSIS

           #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

### 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 in stdio(3).  If the advance is at the right  mar-
           gin:

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

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

           o   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:

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

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

           o   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.

           o   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  and
           addch.)   See  the curs_attr(3x) page for values of prede-
           fined 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, 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  fam-
           ily.   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 configu-
           ration requires Unicode but the library is unable  to  use
           Unicode.

           The names are taken from VT100 nomenclature.

           Name           Default   Description
           --------------------------------------------------
           ACS_BLOCK      #         solid square block
           ACS_BOARD      #         board of squares
           ACS_BTEE       +         bottom tee
           ACS_BULLET     o         bullet
           ACS_CKBOARD    :         checker board (stipple)
           ACS_DARROW     v         arrow pointing down
           ACS_DEGREE     '         degree symbol
           ACS_DIAMOND    +         diamond
           ACS_GEQUAL     >         greater-than-or-equal-to
           ACS_HLINE      -         horizontal line
           ACS_LANTERN    #         lantern symbol
           ACS_LARROW     <         arrow pointing left
           ACS_LEQUAL     <         less-than-or-equal-to
           ACS_LLCORNER   +         lower left-hand corner
           ACS_LRCORNER   +         lower right-hand corner
           ACS_LTEE       +         left tee
           ACS_NEQUAL     !         not-equal
           ACS_PI         *         greek pi
           ACS_PLMINUS    #         plus/minus
           ACS_PLUS       +         plus
           ACS_RARROW     >         arrow pointing right
           ACS_RTEE       +         right tee
           ACS_S1         -         scan line 1
           ACS_S3         -         scan line 3
           ACS_S7         -         scan line 7
           ACS_S9         _         scan line 9
           ACS_STERLING   f         pound-sterling symbol
           ACS_TTEE       +         top tee
           ACS_UARROW     ^         arrow pointing up
           ACS_ULCORNER   +         upper left-hand corner
           ACS_URCORNER   +         upper right-hand corner
           ACS_VLINE      |         vertical line

## RETURN VALUE

           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 other-
           wise noted in the preceding routine descriptions.

           Functions with a "mv" prefix first perform a cursor  move-
           ment  using  wmove, and return an error if the position is
           outside the window, or if the window pointer is null.

## NOTES

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

## PORTABILITY

           All  these functions are described in the XSI Curses stan-
           dard, 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

           o   the library configuration, i.e., ncurses versus ncurs-
               esw, where the latter is capable of displaying Unicode
               while the former is not, and

           o   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 discus-
           sion 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

           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).

                                                             curs_addch(3x)