scanw, wscanw, mvscanw, mvwscanw, vwscanw, vw_scanw - con-
vert 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(3)]. The effect of these routines is as
though wgetstr were called on the window, and the result-
ing 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.
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 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 move-
ment using wmove, and return an error if the position is
outside the window, or if the window pointer is null.
The XSI Curses standard, Issue 4 describes these func-
tions. The function vwscanw is marked TO BE WITHDRAWN,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, Ver-
sion 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
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 applica-
tions should only test if the return value is ERR, since
the OK value (zero) is likely to be misleading. One pos-
sible 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(3)