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31 * https://minnie.tuhs.org/cgi-bin/utree.pl?file=4BSD/usr/src/lib/\
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35 * either header declares "va_list", but only one can be used
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47 <H1 class="no-header">curs_scanw 3x 2023-12-17 ncurses 6.4 Library calls</H1>
49 <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>
54 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
55 <STRONG>scanw</STRONG>, <STRONG>wscanw</STRONG>, <STRONG>mvscanw</STRONG>, <STRONG>mvwscanw</STRONG>, <STRONG>vwscanw</STRONG>, <STRONG>vw_scanw</STRONG> - read formatted
56 input from a <EM>curses</EM> window
59 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
60 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
62 <STRONG>int</STRONG> <STRONG>scanw(const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>fmt</EM><STRONG>,</STRONG> <STRONG>...);</STRONG>
63 <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>
64 <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>
65 <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>
67 <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>
69 <EM>/*</EM> <EM>obsolete</EM> <EM>*/</EM>
70 <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>
73 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
74 <STRONG>scanw</STRONG>, <STRONG>wscanw</STRONG>, <STRONG>mvscanw</STRONG>, and <STRONG>mvwscanw</STRONG> are analogous to <STRONG>scanf(3)</STRONG>. In
75 effect, they call <STRONG><A HREF="curs_getstr.3x.html">wgetstr(3x)</A></STRONG> with <EM>win</EM> (or <STRONG>stdscr</STRONG>) as its first
76 argument, then attempt conversion of the resulting string with
77 <STRONG>vsscanf(3)</STRONG>. Fields in the string that do not map to a variable in the
78 <EM>fmt</EM> parameter are discarded.
80 <STRONG>vwscanw</STRONG> and <STRONG>vw_scanw</STRONG> are analogous to <STRONG>vscanf(3)</STRONG>, and perform a <STRONG>wscanw</STRONG>
81 using a variable argument list. The third argument is a <EM>va</EM><STRONG>_</STRONG><EM>list</EM>, a
82 pointer to a list of arguments, as defined in <EM>stdarg.h</EM>.
85 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
86 These functions return <STRONG>ERR</STRONG> upon failure and otherwise a count of
87 successful conversions; this quantity may be zero.
89 In <EM>ncurses,</EM> failure occurs if <STRONG>vsscanf(3)</STRONG> returns <STRONG>EOF</STRONG>, or if the window
90 pointer <EM>win</EM> is null.
92 Functions with a "mv" prefix first perform a cursor movement using
93 <STRONG>wmove</STRONG>, and fail if the position is outside the window.
96 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
97 No wide character counterpart functions are defined by the "wide"
98 <EM>ncurses</EM> configuration nor by any standard. They are unnecessary: to
99 retrieve and convert a wide-character string from a <EM>curses</EM> terminal
100 keyboard, use these functions with the <STRONG>scanf(3)</STRONG> conversions "%lc" and
101 "%ls" for wide characters and strings, respectively.
103 <EM>ncurses</EM> implements <STRONG>vsscanf(3)</STRONG> internally if it is unavailable when the
104 library is configured.
107 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
108 X/Open Curses, Issue 4, describes these functions. It specifies no
109 error conditions for them.
111 <EM>ncurses</EM> defines <STRONG>vw_scanw</STRONG> and <STRONG>vwscanw</STRONG> identically to support legacy
112 applications. However, the latter is obsolete.
114 <STRONG>o</STRONG> X/Open Curses, Issue 4, Version 2 (1996), marked <STRONG>vwscanw</STRONG> as
115 requiring <EM>varargs.h</EM> and "TO BE WITHDRAWN", and specified <STRONG>vw_scanw</STRONG>
116 using the <EM>stdarg.h</EM> interface.
118 <STRONG>o</STRONG> X/Open Curses, Issue 5, Draft 2 (December 2007) marked <STRONG>vwscanw</STRONG>
119 (along with <STRONG>vwscanw</STRONG> and the termcap interface) as withdrawn. After
120 incorporating review comments, this became X/Open Curses, Issue 7
123 <STRONG>o</STRONG> <EM>ncurses</EM> provides <STRONG>vwscanw</STRONG>, but marks it as deprecated.
125 X/Open Curses Issues 4 and 7 both state that these functions return <STRONG>ERR</STRONG>
126 or <STRONG>OK</STRONG>. This is likely an erratum.
128 <STRONG>o</STRONG> Since the underlying <STRONG>scanf(3)</STRONG> returns the number of successful
129 conversions, and SVr4 <EM>curses</EM> was documented to use this feature,
130 this may have been an editorial solecism introduced by X/Open,
131 rather than an intentional change.
133 <STRONG>o</STRONG> This implementation retains compatibility with SVr4 <EM>curses.</EM> As of
134 2018, NetBSD <EM>curses</EM> also returns the number of successful
135 conversions. Both <EM>ncurses</EM> and NetBSD <EM>curses</EM> call <STRONG>vsscanf(3)</STRONG> to
136 scan the string, which returns <STRONG>EOF</STRONG> on error.
138 <STRONG>o</STRONG> Portable applications should test only if the return value is <STRONG>ERR</STRONG>,
139 and not compare it to <STRONG>OK</STRONG>, since that value (zero) might be
142 One portable way to get useful results would be to use a "%n"
143 conversion at the end of the format string, and check the value of
144 the corresponding variable to determine how many conversions
148 </PRE><H2><a name="h2-HISTORY">HISTORY</a></H2><PRE>
149 <STRONG>scanw</STRONG> was implemented in 4BSD (November 1980); that early version of
150 <EM>curses</EM> preceded the ANSI C standard of 1989. The function was unused
151 in Berkeley distributions for over ten years, until 4.4BSD, which
152 employed it in a game. The 4BSD <STRONG>scanw</STRONG> did not use <EM>varargs.h</EM>, though
153 that had been available since Seventh Edition Unix (1979). In 1991 (a
154 couple of years after SVr4 was generally available, and after the C
155 standard was published), other developers updated the library, using
156 <EM>stdarg.h</EM> internally in 4.4BSD <EM>curses.</EM> Even with this improvement, BSD
157 <EM>curses</EM> did not use function prototypes (nor even declare functions) in
158 <EM>curses.h</EM> until 1992.
160 SVr2 (1984) documented <STRONG>scanw</STRONG> and <STRONG>wscanw</STRONG> tersely as "scanf through
161 <STRONG>stdscr</STRONG>" and "scanf through <EM>win</EM>", respectively.
163 SVr3 (1987) added <STRONG>mvscanw</STRONG>, and <STRONG>mvwscanw</STRONG>, stating
165 These routines correspond to <STRONG>scanf(3S)</STRONG>, as do their arguments
166 and return values. <STRONG>wgetstr</STRONG>() is called on the window, and the
167 resulting line is used as input for the scan.
169 SVr3 also implemented <STRONG>vwscanw</STRONG>, describing its third parameter as a
170 <EM>va</EM><STRONG>_</STRONG><EM>list</EM>, defined in <EM>varargs.h</EM>, and referred the reader to the manual
171 pages for <EM>varargs</EM> and <EM>vprintf</EM> for detailed descriptions. (Because the
172 SVr3 documentation does not mention <EM>vscanf</EM>, the reference to <EM>vprintf</EM>
173 might not be an error).
175 SVr4 (1989) introduced no new variations of <EM>scanw</EM>, but provided for
176 using either <EM>varargs.h</EM> or <EM>stdarg.h</EM> to define the <EM>va</EM><STRONG>_</STRONG><EM>list</EM> type.
178 X/Open Curses, Issue 4 (1995), defined <EM>vw</EM><STRONG>_</STRONG><EM>scanw</EM> to replace <EM>vwscanw</EM>,
179 stating that its <EM>va</EM><STRONG>_</STRONG><EM>list</EM> type is defined in <EM>stdarg.h</EM>.
182 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
183 <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>scanf(3)</STRONG>, <STRONG>vscanf(3)</STRONG>
187 ncurses 6.4 2023-12-17 <STRONG><A HREF="curs_scanw.3x.html">curs_scanw(3x)</A></STRONG>
191 <li><a href="#h2-NAME">NAME</a></li>
192 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
193 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
194 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
195 <li><a href="#h2-NOTES">NOTES</a></li>
196 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
197 <li><a href="#h2-HISTORY">HISTORY</a></li>
198 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>