ncurses 6.2 - patch 20210626
[ncurses.git] / doc / html / man / form_field_buffer.3x.html
1 <!--
2   * t
3   ****************************************************************************
4   * Copyright 2018-2019,2020 Thomas E. Dickey                                *
5   * Copyright 1998-2010,2017 Free Software Foundation, Inc.                  *
6   *                                                                          *
7   * Permission is hereby granted, free of charge, to any person obtaining a  *
8   * copy of this software and associated documentation files (the            *
9   * "Software"), to deal in the Software without restriction, including      *
10   * without limitation the rights to use, copy, modify, merge, publish,      *
11   * distribute, distribute with modifications, sublicense, and/or sell       *
12   * copies of the Software, and to permit persons to whom the Software is    *
13   * furnished to do so, subject to the following conditions:                 *
14   *                                                                          *
15   * The above copyright notice and this permission notice shall be included  *
16   * in all copies or substantial portions of the Software.                   *
17   *                                                                          *
18   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
19   * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
20   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
21   * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
22   * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
23   * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
24   * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
25   *                                                                          *
26   * Except as contained in this notice, the name(s) of the above copyright   *
27   * holders shall not be used in advertising or otherwise to promote the     *
28   * sale, use or other dealings in this Software without prior written       *
29   * authorization.                                                           *
30   ****************************************************************************
31   * @Id: form_field_buffer.3x,v 1.27 2020/10/24 09:27:17 tom Exp @
32 -->
33 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
34 <HTML>
35 <HEAD>
36 <meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
37 <meta name="generator" content="Manpage converted by man2html - see https://invisible-island.net/scripts/readme.html#others_scripts">
38 <TITLE>form_field_buffer 3x</TITLE>
39 <link rel="author" href="mailto:bug-ncurses@gnu.org">
40 <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
41 </HEAD>
42 <BODY>
43 <H1 class="no-header">form_field_buffer 3x</H1>
44 <PRE>
45 <STRONG><A HREF="form_field_buffer.3x.html">form_field_buffer(3x)</A></STRONG>                                    <STRONG><A HREF="form_field_buffer.3x.html">form_field_buffer(3x)</A></STRONG>
46
47
48
49
50 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
51        <STRONG>form_field_buffer</STRONG> - field buffer control
52
53
54 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
55        <STRONG>#include</STRONG> <STRONG>&lt;form.h&gt;</STRONG>
56
57        <STRONG>int</STRONG> <STRONG>set_field_buffer(FIELD</STRONG> <STRONG>*</STRONG><EM>field</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>buf</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>value</EM><STRONG>);</STRONG>
58        <STRONG>char</STRONG> <STRONG>*field_buffer(const</STRONG> <STRONG>FIELD</STRONG> <STRONG>*</STRONG><EM>field</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>buffer</EM><STRONG>);</STRONG>
59
60        <STRONG>int</STRONG> <STRONG>set_field_status(FIELD</STRONG> <STRONG>*</STRONG><EM>field</EM><STRONG>,</STRONG> <STRONG>bool</STRONG> <EM>status</EM><STRONG>);</STRONG>
61        <STRONG>bool</STRONG> <STRONG>field_status(const</STRONG> <STRONG>FIELD</STRONG> <STRONG>*</STRONG><EM>field</EM><STRONG>);</STRONG>
62
63        <STRONG>int</STRONG> <STRONG>set_max_field(FIELD</STRONG> <STRONG>*</STRONG><EM>field</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>max</EM><STRONG>);</STRONG>
64
65
66 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
67        The  function  <STRONG>set_field_buffer</STRONG>  sets  the numbered buffer of the given
68        field to contain a given string:
69
70           <STRONG>o</STRONG>   Buffer 0 is the displayed value of the field.
71
72           <STRONG>o</STRONG>   Other numbered buffers may be allocated by applications  through
73               the  <STRONG>nbuf</STRONG>  argument  of  (see  <STRONG><A HREF="form_field_new.3x.html">form_field_new(3x)</A></STRONG>)  but  are not
74               manipulated by the forms library.
75
76        The function <STRONG>field_buffer</STRONG> returns a pointer  to  the  contents  of  the
77        given numbered buffer:
78
79           <STRONG>o</STRONG>   The  buffer contents always have the same length, and are padded
80               with trailing spaces as needed to  ensure  this  length  is  the
81               same.
82
83           <STRONG>o</STRONG>   The  buffer  may contain leading spaces, depending on how it was
84               set.
85
86           <STRONG>o</STRONG>   The buffer contents are set with <STRONG>set_field_buffer</STRONG>, or as a  side
87               effect of any editing operations on the corresponding field.
88
89           <STRONG>o</STRONG>   Editing  operations  are  based on the <EM>window</EM> which displays the
90               field, rather than a <EM>string</EM>.  The window contains only printable
91               characters,  and  is  filled  with  blanks.  If you want the raw
92               data, you must write your own routine that copies the value  out
93               of the buffer and removes the leading and trailing spaces.
94
95           <STRONG>o</STRONG>   Because  editing  operations change the content of the buffer to
96               correspond to the window, you should not rely on  using  buffers
97               for long-term storage of form data.
98
99        The function <STRONG>set_field_status</STRONG> sets the associated status flag of <EM>field</EM>;
100        <STRONG>field_status</STRONG> gets the current value.  The  status  flag  is  set  to  a
101        nonzero value whenever the field changes.
102
103        The  function  <STRONG>set_max_field</STRONG> sets the maximum size for a dynamic field.
104        An argument of 0 turns off any maximum size threshold for that field.
105
106
107 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
108        The <STRONG>field_buffer</STRONG>  function  returns  NULL  on  error.   It  sets  <STRONG>errno</STRONG>
109        according to their success:
110
111        <STRONG>E_OK</STRONG> The routine succeeded.
112
113        <STRONG>E_BAD_ARGUMENT</STRONG>
114             Routine detected an incorrect or out-of-range argument.
115
116        The <STRONG>field_status</STRONG> function returns <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG>.
117
118        The remaining routines return one of the following:
119
120        <STRONG>E_OK</STRONG> The routine succeeded.
121
122        <STRONG>E_SYSTEM_ERROR</STRONG>
123             System error occurred (see <STRONG>errno(3)</STRONG>).
124
125        <STRONG>E_BAD_ARGUMENT</STRONG>
126             Routine detected an incorrect or out-of-range argument.
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>  and  related  pages  whose names begin "form_" for detailed
131        descriptions of the entry points.
132
133
134 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
135        The header file <STRONG>&lt;form.h&gt;</STRONG> automatically includes the header file
136
137        When configured for wide characters, <STRONG>field_buffer</STRONG> returns a pointer  to
138        temporary   storage   (allocated   and  freed  by  the  library).   The
139        application should not attempt to modify the data.  It will be freed on
140        the next call to <STRONG>field_buffer</STRONG> to return the same buffer.  <STRONG>&lt;curses.h&gt;</STRONG>.
141
142
143 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
144        These  routines  emulate  the  System  V  forms library.  They were not
145        supported on Version 7 or BSD versions.
146
147        The  <STRONG>set_max_field</STRONG>   function   checks   for   an   ncurses   extension
148        <STRONG>O_INPUT_FIELD</STRONG>  which  allows a dynamic field to shrink if the new limit
149        is smaller than the current field size.
150
151
152 </PRE><H2><a name="h2-AUTHORS">AUTHORS</a></H2><PRE>
153        Juergen Pfeifer.  Manual pages and adaptation for new curses by Eric S.
154        Raymond.
155
156
157
158                                                          <STRONG><A HREF="form_field_buffer.3x.html">form_field_buffer(3x)</A></STRONG>
159 </PRE>
160 <div class="nav">
161 <ul>
162 <li><a href="#h2-NAME">NAME</a></li>
163 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
164 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
165 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
166 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
167 <li><a href="#h2-NOTES">NOTES</a></li>
168 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
169 <li><a href="#h2-AUTHORS">AUTHORS</a></li>
170 </ul>
171 </div>
172 </BODY>
173 </HTML>