scanw, wscanw, mvscanw, mvwscanw, vwscanw, vw_scanw - convert formatted
input from a curses window
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);
The scanw, wscanw and mvscanw routines are analogous to scanf [see
scanf(3S)]. 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
The vwscanw and vw_scanw routines are analogous to vscanf. They per‐
form 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.
The XSI Curses standard, Issue 4 describes these functions. The func‐
tion vwscanw is marked TO BE WITHDRAWN, and is to be replaced by a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 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 ALSOcurses(3X), curs_getstr(3X), curs_printw(3X), scanf(3S)curs_scanw(3X)