Provided by: ncurses-doc_6.0+20160213-1ubuntu1_all bug


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


       #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);


   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 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

       ·   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 and  addch.)   See  the  attr(3NCURSES)
       page  for  values  of predefined video attribute constants that can be usefully OR'ed into

   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 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.

       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


       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.


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


       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

       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(3NCURSES).

       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

       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.


       ncurses(3NCURSES),  attr(3NCURSES),  clear(3NCURSES),  inch(3NCURSES),  outopts(3NCURSES),
       refresh(3NCURSES), curses_variables(3NCURSES), putc(3).

       Comparable   functions   in   the  wide-character  (ncursesw)  library  are  described  in