curs_scanw(3X)                                                curs_scanw(3X)

NAME         top

       scanw, wscanw, mvscanw, mvwscanw, vwscanw, vw_scanw - convert format‐
       ted input from a curses window

SYNOPSIS         top

       #include <curses.h>

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

DESCRIPTION         top

       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
       sscanf(3).  Fields which do not map to a variable in the fmt field
       are lost.

       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

RETURN VALUE         top

       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.

PORTABILITY         top

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       function vwscanw is marked TO BE WITHDRAWN, and is to be replaced by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

       Both XSI and The Single Unix Specification, Version 2 state that
       these functions return ERR or OK.  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.  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" conversion at the end of the
       format string to ensure that something was processed.

SEE ALSO         top

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

COLOPHON         top

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