# curs_pad 3x

    curs_pad(3x)                                               curs_pad(3x)

## NAME

           newpad, subpad, prefresh, pnoutrefresh, pechochar,
           pecho_wchar - create and display curses pads

## SYNOPSIS

           #include <curses.h>

           WINDOW *newpad(int nlines, int ncols);
           WINDOW *subpad(WINDOW *orig, int nlines, int ncols,
                 int begin_y, int begin_x);
           int prefresh(WINDOW *pad, int pminrow, int pmincol,
                 int sminrow, int smincol, int smaxrow, int smaxcol);
           int pnoutrefresh(WINDOW *pad, int pminrow, int pmincol,
                 int sminrow, int smincol, int smaxrow, int smaxcol);
           int pechochar(WINDOW *pad, chtype ch);
           int pecho_wchar(WINDOW *pad, const cchar_t *wch);

## DESCRIPTION

           The newpad routine creates and returns a pointer to a  new
           pad data structure with the given number of lines, nlines,
           and columns, ncols.  A pad is like a window,  except  that
           it is not restricted by the screen size, and is not neces-
           sarily associated with a particular part  of  the  screen.
           Pads can be used when a large window is needed, and only a
           part of the window will be on the screen at one time.  Au-
           tomatic refreshes of pads (e.g., from scrolling or echoing
           of input) do not occur.  It is not legal to call  wrefresh
           with  a  pad  as  an  argument;  the  routines prefresh or
           pnoutrefresh should be called instead.   Note  that  these
           routines require additional parameters to specify the part
           of the pad to be displayed and the location on the  screen
           to be used for the display.

           The subpad routine creates and returns a pointer to a sub-
           window within a  pad  with  the  given  number  of  lines,
           nlines,  and  columns,  ncols.   Unlike subwin, which uses
           screen coordinates, the window is  at  position  (begin_x,
           begin_y)  on the pad.  The window is made in the middle of
           the window orig, so that changes made to one window affect
           both windows.  During the use of this routine, it will of-
           ten be necessary to call touchwin or touchline on orig be-
           fore calling prefresh.

           The  prefresh  and  pnoutrefresh routines are analogous to
           wrefresh and wnoutrefresh except that they relate to  pads
           instead  of windows.  The additional parameters are needed
           to indicate what part of the pad and screen are  involved.
           pminrow  and pmincol specify the upper left-hand corner of
           the rectangle to be displayed in the pad.  sminrow,  smin-
           col, smaxrow, and smaxcol specify the edges of the rectan-
           gle to be displayed on the screen.  The  lower  right-hand
           corner of the rectangle to be displayed in the pad is cal-
           culated from the screen coordinates, since the  rectangles
           must  be  the same size.  Both rectangles must be entirely
           contained within their  respective  structures.   Negative
           values of pminrow, pmincol, sminrow, or smincol are treat-
           ed as if they were zero.

           The pechochar routine is functionally equivalent to a call
           to  addch  followed by a call to refresh, a call to waddch
           followed by a call to wrefresh, or a call to  waddch  fol-
           lowed  by  a  call to prefresh.  The knowledge that only a
           single character is being output is taken into  considera-
           tion  and, for non-control characters, a considerable per-
           formance gain might be seen by using  these  routines  in-
           stead of their equivalents.  In the case of pechochar, the
           last location of the pad on the screen is reused  for  the
           arguments to prefresh.

           The  pecho_wchar  function is the analogous wide-character
           form of pechochar.  It outputs one character to a pad  and
           immediately  refreshes the pad.  It does this by a call to
           wadd_wch followed by a call to prefresh.

## RETURN VALUE

           Routines that return an integer return  ERR  upon  failure
           and  OK  (SVr4 only specifies "an integer value other than
           ERR") upon successful completion.

           Routines that return pointers return NULL  on  error,  and
           set errno to ENOMEM.

           X/Open  does not define any error conditions.  In this im-
           plementation

                  prefresh and pnoutrefresh
                       return an error if the window pointer is null,
                       or if the window is not really a pad or if the
                       area to refresh extends off-screen or  if  the
                       minimum coordinates are greater than the maxi-
                       mum.

                  pechochar
                       returns an error if the window is not really a
                       pad,  and the associated call to wechochar re-
                       turns an error.

                  pecho_wchar
                       returns an error if the window is not really a
                       pad,  and  the  associated call to wecho_wchar
                       returns an error.

## NOTES

           Note that pechochar may be a macro.

## PORTABILITY

           The XSI Curses standard, Issue  4  describes  these  func-
           tions.

## SEE ALSO

           curses(3x),  curs_refresh(3x),  curs_touch(3x),  curs_add-
           ch(3x).

                                                               curs_pad(3x)