ncurses 6.1 - patch 20190518
[ncurses.git] / doc / html / man / curs_scanw.3x.html
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41 <H1 class="no-header">curs_scanw 3x</H1>
42 <PRE>
43 <STRONG><A HREF="curs_scanw.3x.html">curs_scanw(3x)</A></STRONG>                                                  <STRONG><A HREF="curs_scanw.3x.html">curs_scanw(3x)</A></STRONG>
44
45
46
47
48 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
49        <STRONG>scanw</STRONG>, <STRONG>wscanw</STRONG>, <STRONG>mvscanw</STRONG>, <STRONG>mvwscanw</STRONG>, <STRONG>vwscanw</STRONG>, <STRONG>vw_scanw</STRONG> - convert formatted
50        input from a <STRONG>curses</STRONG> window
51
52
53 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
54        <STRONG>#include</STRONG> <STRONG>&lt;curses.h&gt;</STRONG>
55
56        <STRONG>int</STRONG> <STRONG>scanw(const</STRONG> <STRONG>char</STRONG> <STRONG>*fmt,</STRONG> <STRONG>...);</STRONG>
57        <STRONG>int</STRONG> <STRONG>wscanw(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*fmt,</STRONG> <STRONG>...);</STRONG>
58        <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>
59        <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>
60        <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>
61
62        /* obsolete */
63        <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>
64
65
66 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
67        The <STRONG>scanw</STRONG>, <STRONG>wscanw</STRONG> and <STRONG>mvscanw</STRONG> routines  are  analogous  to  <STRONG>scanf</STRONG>  [see
68        <STRONG>scanf(3)</STRONG>].   The  effect  of  these  routines is as though <STRONG>wgetstr</STRONG> were
69        called on the  window,  and  the  resulting  line  used  as  input  for
70        <STRONG>sscanf(3)</STRONG>.   Fields which do not map to a variable in the <EM>fmt</EM> field are
71        lost.
72
73        The <STRONG>vwscanw</STRONG> and <STRONG>vw_scanw</STRONG> routines are  analogous  to  <STRONG>vscanf(3)</STRONG>.   They
74        perform a <STRONG>wscanw</STRONG> using a variable argument list.  The third argument is
75        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>.
76
77
78 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
79        <STRONG>vwscanw</STRONG> returns <STRONG>ERR</STRONG> on failure and an integer equal to  the  number  of
80        fields scanned on success.
81
82        Applications  may  use the return value from the <STRONG>scanw</STRONG>, <STRONG>wscanw</STRONG>, <STRONG>mvscanw</STRONG>
83        and <STRONG>mvwscanw</STRONG> routines to determine the  number  of  fields  which  were
84        mapped in the call.
85
86        Functions  with  a  "mv"  prefix  first perform a cursor movement using
87        <STRONG>wmove</STRONG>, and return an error if the position is outside the window, or if
88        the window pointer is null.
89
90
91 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
92        In this implementation, <STRONG>vw_scanw</STRONG> and <STRONG>vwscanw</STRONG> are equivalent, to support
93        legacy applications.  However, the latter (<STRONG>vwscanw</STRONG>) is obsolete:
94
95        <STRONG>o</STRONG>   The XSI Curses standard, Issue 4 described these functions,  noting
96            that  the  function <STRONG>vwscanw</STRONG> is marked TO BE WITHDRAWN, and is to be
97            replaced by a function <STRONG>vw_scanw</STRONG> using the <STRONG>&lt;stdarg.h&gt;</STRONG> interface.
98
99        <STRONG>o</STRONG>   The Single Unix Specification, Version 2 states that  <STRONG>vw_scanw</STRONG>   is
100            preferred   to   <STRONG>vwscanw</STRONG>   since   the  latter  requires  including
101            <STRONG>&lt;varargs.h&gt;</STRONG>, which cannot be used in the same file  as  <STRONG>&lt;stdarg.h&gt;</STRONG>.
102            This  implementation  uses <STRONG>&lt;stdarg.h&gt;</STRONG> for both, because that header
103            is included in <STRONG>&lt;curses.h</STRONG>&gt;.
104
105        <STRONG>o</STRONG>   X/Open Curses, Issue 5 (December 2007) marked <STRONG>vwscanw</STRONG>  (along  with
106            <STRONG>vwprintw</STRONG> and the termcap interface) as withdrawn.
107
108        Both  XSI and The Single Unix Specification, Version 2 state that these
109        functions return <STRONG>ERR</STRONG> or <STRONG>OK</STRONG>.
110
111        <STRONG>o</STRONG>   Since the underlying  <STRONG>scanf(3)</STRONG>  can  return  the  number  of  items
112            scanned, and the SVr4 code was documented to use this feature, this
113            is probably an editing error which was introduced  in  XSI,  rather
114            than being done intentionally.
115
116        <STRONG>o</STRONG>   This  implementation  returns the number of items scanned, for com-
117            patibility with SVr4  curses.   As  of  2018,  NetBSD  curses  also
118            returns  the  number  of  items  scanned.   Both ncurses and NetBSD
119            curses call <STRONG>vsscanf</STRONG> to scan the string, which returns <STRONG>EOF</STRONG> on error.
120
121        <STRONG>o</STRONG>   Portable applications should only test if the return value is  <STRONG>ERR</STRONG>,
122            since the <STRONG>OK</STRONG> value (zero) is likely to be misleading.
123
124            One  possible way to get useful results would be to use a "%n" con-
125            version at the end of the format string to  ensure  that  something
126            was processed.
127
128
129 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
130        <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>,
131        <STRONG>scanf(3)</STRONG>.
132
133
134
135                                                                 <STRONG><A HREF="curs_scanw.3x.html">curs_scanw(3x)</A></STRONG>
136 </PRE>
137 <div class="nav">
138 <ul>
139 <li><a href="#h2-NAME">NAME</a></li>
140 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
141 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
142 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
143 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
144 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
145 </ul>
146 </div>
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