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- * @Id: curs_scanw.3x,v 1.41 2023/10/07 21:19:07 tom Exp @
+ * @Id: curs_scanw.3x,v 1.43 2023/11/25 11:31:06 tom Exp @
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-<H1 class="no-header">curs_scanw 3x 2023-10-07 ncurses 6.4 Library calls</H1>
+<H1 class="no-header">curs_scanw 3x 2023-11-25 ncurses 6.4 Library calls</H1>
<PRE>
<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>
the window pointer is null.
+</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) is obsolete: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 is marked TO BE WITHDRAWN, and is to be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 and the termcap interface) as withdrawn.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-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
<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 2023-1
0-07 <STRONG><A HREF="curs_scanw.3x.html">curs_scanw(3x)</A></STRONG>
+ncurses 6.4 2023-1
1-25 <STRONG><A HREF="curs_scanw.3x.html">curs_scanw(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<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-HISTORY">HISTORY</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
</div>
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