.\"***************************************************************************
-.\" Copyright (c) 1998 Free Software Foundation, Inc. *
+.\" Copyright (c) 1998-2006,2010 Free Software Foundation, Inc. *
.\" *
.\" Permission is hereby granted, free of charge, to any person obtaining a *
.\" copy of this software and associated documentation files (the *
.\" authorization. *
.\"***************************************************************************
.\"
-.\" $Id: curs_scanw.3x,v 1.8 1998/12/26 20:10:12 tom Exp $
+.\" $Id: curs_scanw.3x,v 1.17 2010/12/04 18:40:45 tom Exp $
.TH curs_scanw 3X ""
.SH NAME
-\fBscanw\fR, \fBwscanw\fR, \fBmvscanw\fR,
-\fBmvwscanw\fR, \fBvwscanw\fR - convert formatted input from a
-\fBcurses\fR widow
+\fBscanw\fR,
+\fBwscanw\fR,
+\fBmvscanw\fR,
+\fBmvwscanw\fR,
+\fBvwscanw\fR, \fBvw_scanw\fR \- convert formatted input from a \fBcurses\fR window
.SH SYNOPSIS
\fB#include <curses.h>\fR
-
-\fBint scanw(char *fmt\fR [\fB, arg\fR] \fB...);\fR
+.sp
+\fBint scanw(char *fmt, ...);\fR
.br
-\fBint wscanw(WINDOW *win, char *fmt\fR [\fB, arg\fR] \fB...);\fR
+\fBint wscanw(WINDOW *win, char *fmt, ...);\fR
.br
-\fBint mvscanw(int y, int x, char *fmt\fR [\fB, arg\fR] \fB...);\fR
+\fBint mvscanw(int y, int x, char *fmt, ...);\fR
.br
-\fBint mvwscanw(WINDOW *win, int y, int x,\fR
- \fBchar *fmt\fR [\fB, arg]\fR \fB...);\fR
+\fBint mvwscanw(WINDOW *win, int y, int x, char *fmt, ...);\fR
+.br
+\fBint vw_scanw(WINDOW *win, char *fmt, va_list varglist);\fR
.br
\fBint vwscanw(WINDOW *win, char *fmt, va_list varglist);\fR
.SH DESCRIPTION
The \fBscanw\fR, \fBwscanw\fR and \fBmvscanw\fR routines are analogous to
-\fBscanf\fR [see \fBscanf\fR(3S)]. The effect of these routines is as though
+\fBscanf\fR [see \fBscanf\fR(3)]. The effect of these routines is as though
\fBwgetstr\fR were called on the window, and the resulting line used as input
for \fBsscanf\fR(3). Fields which do not map to a variable in the \fIfmt\fR
field are lost.
-
-The \fBvwscanw\fR routine is similar to \fBvwprintw\fR in that it performs a
-\fBwscanw\fR using a variable argument list. The third argument is a
-\fIva\fR_\fIlist\fR, a pointer to a list of arguments, as defined in
-\fB<varargs.h>\fR.
+.PP
+The \fBvwscanw\fR and \fBvw_scanw\fR routines are analogous to \fBvscanf\fR.
+They perform a \fBwscanw\fR using a variable argument list.
+The third argument is a \fIva_list\fR,
+a pointer to a list of arguments, as defined in \fB<stdarg.h>\fR.
.SH RETURN VALUE
\fBvwscanw\fR returns \fBERR\fR on failure and an integer equal to the
number of fields scanned on success.
-
+.PP
Applications may use the return value from the \fBscanw\fR, \fBwscanw\fR,
\fBmvscanw\fR and \fBmvwscanw\fR routines to determine the number of fields
which were mapped in the call.
+.PP
+Functions with a "mv" prefix first perform a cursor movement using
+\fBwmove\fP, and return an error if the position is outside the window,
+or if the window pointer is null.
.SH PORTABILITY
The XSI Curses standard, Issue 4 describes these functions. The function
\fBvwscanw\fR is marked TO BE WITHDRAWN, and is to be replaced by a function
\fBvw_scanw\fR using the \fB<stdarg.h>\fR interface.
+The Single Unix Specification, Version 2 states that
+\fBvw_scanw\fR is preferred to \fBvwscanw\fR since the latter requires
+including \fB<varargs.h>\fR, which
+cannot be used in the same file as \fB<stdarg.h>\fR.
+This implementation uses \fB<stdarg.h>\fR for both, because that header
+is included in \fB<curses.h\fR>.
+.LP
+Both XSI and The Single Unix Specification, Version 2 state that these
+functions return ERR or OK.
+Since the underlying \fBscanf\fR 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.
.SH SEE ALSO
-\fBcurses\fR(3X), \fBcurs_getstr\fR(3X), \fBcurs_printw\fR(3X), \fBscanf\fR(3S)
-.\"#
-.\"# The following sets edit modes for GNU EMACS
-.\"# Local Variables:
-.\"# mode:nroff
-.\"# fill-column:79
-.\"# End:
+\fBcurses\fR(3X), \fBcurs_getstr\fR(3X), \fBcurs_printw\fR(3X), \fBscanf\fR(3)
projects / ncurses.git / blobdiff