ncurses 6.2 - patch 20200222
[ncurses.git] / doc / html / man / curs_scanw.3x.html
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30   * @Id: curs_scanw.3x,v 1.26 2020/02/02 23:34:34 tom Exp @
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42 <H1 class="no-header">curs_scanw 3x</H1>
43 <PRE>
44 <STRONG><A HREF="curs_scanw.3x.html">curs_scanw(3x)</A></STRONG>                                                  <STRONG><A HREF="curs_scanw.3x.html">curs_scanw(3x)</A></STRONG>
45
46
47
48
49 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
50        <STRONG>scanw</STRONG>, <STRONG>wscanw</STRONG>, <STRONG>mvscanw</STRONG>, <STRONG>mvwscanw</STRONG>, <STRONG>vwscanw</STRONG>, <STRONG>vw_scanw</STRONG> - convert formatted
51        input from a <STRONG>curses</STRONG> window
52
53
54 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
55        <STRONG>#include</STRONG> <STRONG>&lt;curses.h&gt;</STRONG>
56
57        <STRONG>int</STRONG> <STRONG>scanw(const</STRONG> <STRONG>char</STRONG> <STRONG>*fmt,</STRONG> <STRONG>...);</STRONG>
58        <STRONG>int</STRONG> <STRONG>wscanw(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*fmt,</STRONG> <STRONG>...);</STRONG>
59        <STRONG>int</STRONG> <STRONG>mvscanw(int</STRONG> <STRONG>y,</STRONG> <STRONG>int</STRONG> <STRONG>x,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*fmt,</STRONG> <STRONG>...);</STRONG>
60        <STRONG>int</STRONG> <STRONG>mvwscanw(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>int</STRONG> <STRONG>y,</STRONG> <STRONG>int</STRONG> <STRONG>x,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*fmt,</STRONG> <STRONG>...);</STRONG>
61        <STRONG>int</STRONG> <STRONG>vw_scanw(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*fmt,</STRONG> <STRONG>va_list</STRONG> <STRONG>varglist);</STRONG>
62
63        /* obsolete */
64        <STRONG>int</STRONG> <STRONG>vwscanw(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*fmt,</STRONG> <STRONG>va_list</STRONG> <STRONG>varglist);</STRONG>
65
66
67 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
68        The <STRONG>scanw</STRONG>, <STRONG>wscanw</STRONG> and <STRONG>mvscanw</STRONG> routines  are  analogous  to  <STRONG>scanf</STRONG>  [see
69        <STRONG>scanf(3)</STRONG>].   The  effect  of  these  routines is as though <STRONG>wgetstr</STRONG> were
70        called on the  window,  and  the  resulting  line  used  as  input  for
71        <STRONG>sscanf(3)</STRONG>.   Fields which do not map to a variable in the <EM>fmt</EM> field are
72        lost.
73
74        The <STRONG>vwscanw</STRONG> and <STRONG>vw_scanw</STRONG> routines are  analogous  to  <STRONG>vscanf(3)</STRONG>.   They
75        perform a <STRONG>wscanw</STRONG> using a variable argument list.  The third argument is
76        a <EM>va</EM><STRONG>_</STRONG><EM>list</EM>, a pointer to a list of arguments, as defined in <STRONG>&lt;stdarg.h&gt;</STRONG>.
77
78
79 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
80        <STRONG>vwscanw</STRONG> returns <STRONG>ERR</STRONG> on failure and an integer equal to  the  number  of
81        fields scanned on success.
82
83        Applications  may  use the return value from the <STRONG>scanw</STRONG>, <STRONG>wscanw</STRONG>, <STRONG>mvscanw</STRONG>
84        and <STRONG>mvwscanw</STRONG> routines to determine the  number  of  fields  which  were
85        mapped in the call.
86
87        Functions  with  a  "mv"  prefix  first perform a cursor movement using
88        <STRONG>wmove</STRONG>, and return an error if the position is outside the window, or if
89        the window pointer is null.
90
91
92 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
93        In this implementation, <STRONG>vw_scanw</STRONG> and <STRONG>vwscanw</STRONG> are equivalent, to support
94        legacy applications.  However, the latter (<STRONG>vwscanw</STRONG>) is obsolete:
95
96        <STRONG>o</STRONG>   The XSI Curses standard, Issue 4 described these functions,  noting
97            that  the  function <STRONG>vwscanw</STRONG> is marked TO BE WITHDRAWN, and is to be
98            replaced by a function <STRONG>vw_scanw</STRONG> using the <STRONG>&lt;stdarg.h&gt;</STRONG> interface.
99
100        <STRONG>o</STRONG>   The Single Unix Specification, Version 2 states that  <STRONG>vw_scanw</STRONG>   is
101            preferred   to   <STRONG>vwscanw</STRONG>   since   the  latter  requires  including
102            <STRONG>&lt;varargs.h&gt;</STRONG>, which cannot be used in the same file  as  <STRONG>&lt;stdarg.h&gt;</STRONG>.
103            This  implementation  uses <STRONG>&lt;stdarg.h&gt;</STRONG> for both, because that header
104            is included in <STRONG>&lt;curses.h</STRONG>&gt;.
105
106        <STRONG>o</STRONG>   X/Open Curses, Issue 5 (December 2007) marked <STRONG>vwscanw</STRONG>  (along  with
107            <STRONG>vwprintw</STRONG> and the termcap interface) as withdrawn.
108
109        Both  XSI and The Single Unix Specification, Version 2 state that these
110        functions return <STRONG>ERR</STRONG> or <STRONG>OK</STRONG>.
111
112        <STRONG>o</STRONG>   Since the underlying  <STRONG>scanf(3)</STRONG>  can  return  the  number  of  items
113            scanned, and the SVr4 code was documented to use this feature, this
114            is probably an editing error which was introduced  in  XSI,  rather
115            than being done intentionally.
116
117        <STRONG>o</STRONG>   This  implementation  returns the number of items scanned, for com-
118            patibility with SVr4  curses.   As  of  2018,  NetBSD  curses  also
119            returns  the  number  of  items  scanned.   Both ncurses and NetBSD
120            curses call <STRONG>vsscanf</STRONG> to scan the string, which returns <STRONG>EOF</STRONG> on error.
121
122        <STRONG>o</STRONG>   Portable applications should only test if the return value is  <STRONG>ERR</STRONG>,
123            since the <STRONG>OK</STRONG> value (zero) is likely to be misleading.
124
125            One  possible way to get useful results would be to use a "%n" con-
126            version at the end of the format string to  ensure  that  something
127            was processed.
128
129
130 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
131        <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>,
132        <STRONG>scanf(3)</STRONG>.
133
134
135
136                                                                 <STRONG><A HREF="curs_scanw.3x.html">curs_scanw(3x)</A></STRONG>
137 </PRE>
138 <div class="nav">
139 <ul>
140 <li><a href="#h2-NAME">NAME</a></li>
141 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
142 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
143 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
144 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
145 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
146 </ul>
147 </div>
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