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+<H1 class="no-header">curs_scanw 3x 2022-02-12 ncurses 6.4 Library calls</H1>
<PRE>
-<!-- Manpage converted by man2html 3.0.1 -->
+<STRONG><A HREF="curs_scanw.3x.html">curs_scanw(3x)</A></STRONG> Library calls <STRONG><A HREF="curs_scanw.3x.html">curs_scanw(3x)</A></STRONG>
-</PRE>
-<H2>NAME</H2><PRE>
- <B>scanw</B>, <B>wscanw</B>, <B>mvscanw</B>, <B>mvwscanw</B>, <B>vwscanw</B>, <B>vw_scanw</B> - con-
- vert formatted input from a <B>curses</B> window
-</PRE>
-<H2>SYNOPSIS</H2><PRE>
- <B>#include</B> <B><curses.h></B>
- <B>int</B> <B>scanw(char</B> <B>*fmt</B> [<B>,</B> <B>arg</B>] <B>...);</B>
- <B>int</B> <B>wscanw(WINDOW</B> <B>*win,</B> <B>char</B> <B>*fmt</B> [<B>,</B> <B>arg</B>] <B>...);</B>
- <B>int</B> <B>mvscanw(int</B> <B>y,</B> <B>int</B> <B>x,</B> <B>char</B> <B>*fmt</B> [<B>,</B> <B>arg</B>] <B>...);</B>
- <B>int</B> <B>mvwscanw(WINDOW</B> <B>*win,</B> <B>int</B> <B>y,</B> <B>int</B> <B>x,</B>
- <B>char</B> <B>*fmt</B> [<B>,</B> <B>arg]</B> <B>...);</B>
- <B>int</B> <B>vw_scanw(WINDOW</B> <B>*win,</B> <B>char</B> <B>*fmt,</B> <B>va_list</B> <B>varglist);</B>
- <B>int</B> <B>vwscanw(WINDOW</B> <B>*win,</B> <B>char</B> <B>*fmt,</B> <B>va_list</B> <B>varglist);</B>
+</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
+ <STRONG>scanw</STRONG>, <STRONG>wscanw</STRONG>, <STRONG>mvscanw</STRONG>, <STRONG>mvwscanw</STRONG>, <STRONG>vwscanw</STRONG>, <STRONG>vw_scanw</STRONG> - convert formatted
+ input from a <STRONG>curses</STRONG> window
-</PRE>
-<H2>DESCRIPTION</H2><PRE>
- The <B>scanw</B>, <B>wscanw</B> and <B>mvscanw</B> routines are analogous to
- <B>scanf</B> [see <B><A HREF="scanf.3S.html">scanf(3S)</A></B>]. The effect of these routines is as
- though <B>wgetstr</B> were called on the window, and the result-
- ing line used as input for <B><A HREF="sscanf.3.html">sscanf(3)</A></B>. Fields which do not
- map to a variable in the <I>fmt</I> field are lost.
+</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
+ <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
- The <B>vwscanw</B> routine is similar to <B>vwprintw</B> in that it per-
- forms a <B>wscanw</B> using a variable argument list. The third
- argument is a <I>va</I>_<I>list</I>, a pointer to a list of arguments,
- as defined in <B><varargs.h></B>.
+ <STRONG>int</STRONG> <STRONG>scanw(const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>fmt</EM><STRONG>,</STRONG> <STRONG>...);</STRONG>
+ <STRONG>int</STRONG> <STRONG>wscanw(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>fmt</EM><STRONG>,</STRONG> <STRONG>...);</STRONG>
+ <STRONG>int</STRONG> <STRONG>mvscanw(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>fmt</EM><STRONG>,</STRONG> <STRONG>...);</STRONG>
+ <STRONG>int</STRONG> <STRONG>mvwscanw(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>fmt</EM><STRONG>,</STRONG> <STRONG>...);</STRONG>
+ <STRONG>int</STRONG> <STRONG>vw_scanw(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>fmt</EM><STRONG>,</STRONG> <STRONG>va_list</STRONG> <EM>varglist</EM><STRONG>);</STRONG>
-</PRE>
-<H2>RETURN VALUE</H2><PRE>
- <B>vwscanw</B> returns <B>ERR</B> on failure and an integer equal to the
- number of fields scanned on success.
+ /* obsolete */
+ <STRONG>int</STRONG> <STRONG>vwscanw(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>fmt</EM><STRONG>,</STRONG> <STRONG>va_list</STRONG> <EM>varglist</EM><STRONG>);</STRONG>
- Applications may use the return value from the <B>scanw</B>,
- <B>wscanw</B>, <B>mvscanw</B> and <B>mvwscanw</B> routines to determine the
- number of fields which were mapped in the call.
+</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
+ The <STRONG>scanw</STRONG>, <STRONG>wscanw</STRONG> and <STRONG>mvscanw</STRONG> routines are analogous to <STRONG>scanf</STRONG> [see
+ <STRONG>scanf(3)</STRONG>]. The effect of these routines is as though <STRONG>wgetstr</STRONG> were
+ called on the window, and the resulting line used as input for
+ <STRONG>sscanf(3)</STRONG>. Fields which do not map to a variable in the <EM>fmt</EM> field are
+ lost.
-</PRE>
-<H2>PORTABILITY</H2><PRE>
- The XSI Curses standard, Issue 4 describes these func-
- tions. The function <B>vwscanw</B> is marked TO BE WITHDRAWN,
- and is to be replaced by a function <B>vw_scanw</B> using the
- <B><stdarg.h></B> interface.
+ The <STRONG>vwscanw</STRONG> and <STRONG>vw_scanw</STRONG> routines are analogous to <STRONG>vscanf(3)</STRONG>. They
+ perform a <STRONG>wscanw</STRONG> using a variable argument list. The third argument is
+ a <STRONG>va_list</STRONG>, a pointer to a list of arguments, as defined in <STRONG><stdarg.h></STRONG>.
-</PRE>
-<H2>SEE ALSO</H2><PRE>
- <B><A HREF="ncurses.3x.html">curses(3x)</A></B>, <B><A HREF="curs_getstr.3x.html">curs_getstr(3x)</A></B>, <B><A HREF="curs_printw.3x.html">curs_printw(3x)</A></B>, <B><A HREF="scanf.3S.html">scanf(3S)</A></B>
+</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
+ <STRONG>vwscanw</STRONG> returns <STRONG>ERR</STRONG> on failure and an integer equal to the number of
+ fields scanned on success.
+
+ Applications may use the return value from the <STRONG>scanw</STRONG>, <STRONG>wscanw</STRONG>, <STRONG>mvscanw</STRONG>
+ and <STRONG>mvwscanw</STRONG> routines to determine the number of fields which were
+ mapped in the call.
+
+ Functions with a "mv" prefix first perform a cursor movement using
+ <STRONG>wmove</STRONG>, and return an error if the position is outside the window, or if
+ the window pointer is null.
+
+
+</PRE><H2><a name="h2-HISTORY">HISTORY</a></H2><PRE>
+ While <STRONG>scanw</STRONG> was implemented in 4BSD, none of the BSD releases used it
+ until 4.4BSD (in a game). That early version of curses was before the
+ ANSI C standard. It did not use <varargs.h>, though that was
+ available. In 1991 (a couple of years after SVr4 was generally
+ available, and after the C standard was published), other developers
+ updated the library, using <stdarg.h> internally in 4.4BSD curses.
+ Even with this improvement, BSD curses did not use function prototypes
+ (or even declare functions) in the <curses.h> header until 1992.
+
+ SVr2 documented <STRONG>scanw</STRONG>, <STRONG>wscanw</STRONG> tersely as "scanf through <EM>stdscr</EM>" and
+ tersely as "scanf through <EM>win</EM>", respectively.
+
+ SVr3 added <STRONG>mvscanw</STRONG>, and <STRONG>mvwscanw</STRONG>, with a three-line summary saying that
+ they were analogous to <STRONG>scanf(3)</STRONG>, explaining that the string which would
+ be output from <STRONG>scanf(3)</STRONG> would instead be output using <STRONG>waddstr</STRONG> on the
+ given window. SVr3 also added <STRONG>vwscanw</STRONG>, saying that the third parameter
+ is a <STRONG>va_list</STRONG>, defined in <varargs.h>, and referring the reader to the
+ manual pages for <EM>varargs</EM> and <STRONG>vprintf</STRONG> for detailed descriptions.
+ (Because the SVr3 documentation does not mention <STRONG>vscanf</STRONG>, that reference
+ to <STRONG>vprintf</STRONG> may not be an error).
+
+ SVr4 added no new variations of <STRONG>scanw</STRONG>, but provided for using
+ <varargs.h> or <stdarg.h> to define the <STRONG>va_list</STRONG> type.
+
+ X/Open Curses added <STRONG>vw_scanw</STRONG> to replace <STRONG>vwscanw</STRONG>, stating that its
+ <STRONG>va_list</STRONG> definition requires <stdarg.h>.
+
+
+</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
+ In this implementation, <STRONG>vw_scanw</STRONG> and <STRONG>vwscanw</STRONG> are equivalent, to support
+ legacy applications. However, the latter (<STRONG>vwscanw</STRONG>) is obsolete:
+
+ <STRONG>o</STRONG> The XSI Curses standard, Issue 4 described these functions, noting
+ that the function <STRONG>vwscanw</STRONG> is marked TO BE WITHDRAWN, and is to be
+ replaced by a function <STRONG>vw_scanw</STRONG> using the <STRONG><stdarg.h></STRONG> interface.
+
+ <STRONG>o</STRONG> The Single Unix Specification, Version 2 states that <STRONG>vw_scanw</STRONG> is
+ preferred to <STRONG>vwscanw</STRONG> since the latter requires including
+ <STRONG><varargs.h></STRONG>, which cannot be used in the same file as <STRONG><stdarg.h></STRONG>.
+ This implementation uses <STRONG><stdarg.h></STRONG> for both, because that header
+ is included in <STRONG><curses.h</STRONG>>.
+ <STRONG>o</STRONG> X/Open Curses, Issue 5 (December 2007) marked <STRONG>vwscanw</STRONG> (along with
+ <STRONG>vwprintw</STRONG> and the termcap interface) as withdrawn.
+ Both XSI and The Single Unix Specification, Version 2 state that these
+ functions return <STRONG>ERR</STRONG> or <STRONG>OK</STRONG>.
+ <STRONG>o</STRONG> Since the underlying <STRONG>scanf(3)</STRONG> 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.
+ <STRONG>o</STRONG> This implementation returns the number of items scanned, for
+ compatibility with SVr4 curses. As of 2018, NetBSD curses also
+ returns the number of items scanned. Both ncurses and NetBSD
+ curses call <STRONG>vsscanf</STRONG> to scan the string, which returns <STRONG>EOF</STRONG> on error.
+ <STRONG>o</STRONG> Portable applications should only test if the return value is <STRONG>ERR</STRONG>,
+ since the <STRONG>OK</STRONG> 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.
+</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
+ <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_getstr.3x.html">curs_getstr(3x)</A></STRONG>, <STRONG><A HREF="curs_printw.3x.html">curs_printw(3x)</A></STRONG>, <STRONG><A HREF="curs_termcap.3x.html">curs_termcap(3x)</A></STRONG>,
+ <STRONG>scanf(3)</STRONG>.
+ncurses 6.4 2022-02-12 <STRONG><A HREF="curs_scanw.3x.html">curs_scanw(3x)</A></STRONG>
</PRE>
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+<ul>
+<li><a href="#h2-NAME">NAME</a></li>
+<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
+<li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
+<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
+<li><a href="#h2-HISTORY">HISTORY</a></li>
+<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
+<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
+</ul>
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