scanw, wscanw, mvscanw, mvwscanw, vwscanw, vw_scanw - convert formatted input from a
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 perform a wscanw using a
variable argument list. The third argument is a va_list, a pointer to a list of argu-
ments, as defined in <stdarg.h>.
vwscanw returns ERR on failure and an integer equal to the number of fields scanned on
Applications may use the return value from the scanw, wscanw, mvscanw and mvwscanw rou-
tines to determine the number of fields which were mapped in the call.
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marked TO BE WITHDRAWN, and is to be replaced by a function vw_scanw using the 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 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 mislead-
ing. 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.
curses(3X), curs_getstr(3X), curs_printw(3X), scanf(3S)