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curs_scanw(3X)							curs_scanw(3X)

       scanw, wscanw, mvscanw, mvwscanw, vwscanw, vw_scanw - convert formatted
       input from a curses window

       #include	<curses.h>

       int scanw(const char *fmt, ...);
       int wscanw(WINDOW *win, const char *fmt,	...);
       int mvscanw(int y, int x, const char *fmt, ...);
       int mvwscanw(WINDOW *win, int y,	int x, const char *fmt,	...);
       int vw_scanw(WINDOW *win, const char *fmt, va_list varglist);

       /* obsolete */
       int vwscanw(WINDOW *win,	const char *fmt, va_list varglist);

       The scanw, wscanw and mvscanw routines  are  analogous  to  scanf  [see
       scanf(3)].   The	 effect	 of  these  routines is	as though wgetstr were
       called on the window, and the resulting line  used  as  input  for  ss-
       canf(3).	  Fields  which	 do not	map to a variable in the fmt field are

       The vwscanw and vw_scanw	routines are  analogous	 to  vscanf(3).	  They
       perform a wscanw	using a	variable argument list.	 The third argument is
       a va_list, a pointer to a list of arguments, as defined in <stdarg.h>.

       vwscanw returns ERR on failure and an integer equal to  the  number  of
       fields scanned on success.

       Applications  may  use the return value from the	scanw, wscanw, mvscanw
       and mvwscanw routines to	determine the  number  of  fields  which  were
       mapped in the call.

       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.

       In this implementation, vw_scanw	and vwscanw are	equivalent, to support
       legacy applications.  However, the latter (vwscanw) is obsolete:

       o   The XSI Curses standard, Issue 4 described these functions,	noting
	   that	 the  function vwscanw is marked TO BE WITHDRAWN, and is to be
	   replaced by a function vw_scanw using the <stdarg.h>	interface.

       o   The Single Unix Specification, Version 2 states that	 vw_scanw   is
	   preferred   to   vwscanw   since   the  latter  requires  including
	   <varargs.h>,	which cannot be	used in	the same file  as  <stdarg.h>.
	   This	 implementation	 uses <stdarg.h> for both, because that	header
	   is included in <curses.h>.

       o   X/Open Curses, Issue	5 (December 2007) marked vwscanw  (along  with
	   vwprintw and	the termcap interface) as withdrawn.

       Both  XSI and The Single	Unix Specification, Version 2 state that these
       functions return	ERR or OK.

       o   Since the underlying	 scanf(3)  can	return	the  number  of	 items
	   scanned, and	the SVr4 code was documented to	use this feature, this
	   is probably an editing error	which was introduced  in  XSI,	rather
	   than	being done intentionally.

       o   This	 implementation	 returns the number of items scanned, for com-
	   patibility with SVr4	curses.	 As of 2018, NetBSD  curses  also  re-
	   turns  the number of	items scanned.	Both ncurses and NetBSD	curses
	   call	vsscanf	to scan	the string, which returns EOF on error.

       o   Portable applications should	only test if the return	value is  ERR,
	   since the OK	value (zero) is	likely to be misleading.

	   One	possible way to	get useful results would be to use a "%n" con-
	   version at the end of the format string to  ensure  that  something
	   was processed.

       curses(3X), curs_getstr(3X), curs_printw(3X), curs_termcap(3X),



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