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  42 <H1 class="no-header">form_field_buffer 3x 2023-12-16 ncurses 6.4 Library calls</H1>
  43 <PRE>
  44 <STRONG><A HREF="form_field_buffer.3x.html">form_field_buffer(3x)</A></STRONG>            Library calls           <STRONG><A HREF="form_field_buffer.3x.html">form_field_buffer(3x)</A></STRONG>
  45
  46
  47
  48
  49 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
  50        <STRONG>form_field_buffer</STRONG> - field buffer control
  51
  52
  53 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
  54        <STRONG>#include</STRONG> <STRONG>&lt;form.h&gt;</STRONG>
  55
  56        <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>
  57        <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>
  58
  59        <STRONG>int</STRONG> <STRONG>set_field_status(FIELD</STRONG> <STRONG>*</STRONG><EM>field</EM><STRONG>,</STRONG> <STRONG>bool</STRONG> <EM>status</EM><STRONG>);</STRONG>
  60        <STRONG>bool</STRONG> <STRONG>field_status(const</STRONG> <STRONG>FIELD</STRONG> <STRONG>*</STRONG><EM>field</EM><STRONG>);</STRONG>
  61
  62        <STRONG>int</STRONG> <STRONG>set_max_field(FIELD</STRONG> <STRONG>*</STRONG><EM>field</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>max</EM><STRONG>);</STRONG>
  63
  64
  65 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
  66        The  function  <STRONG>set_field_buffer</STRONG>  sets  the numbered buffer of the given
  67        field to contain a given string:
  68
  69           <STRONG>o</STRONG>   Buffer 0 is the displayed value of the field.
  70
  71           <STRONG>o</STRONG>   Other numbered buffers may be allocated by applications  through
  72               the  <STRONG>nbuf</STRONG>  argument  of  (see  <STRONG><A HREF="form_field_new.3x.html">form_field_new(3x)</A></STRONG>)  but  are not
  73               manipulated by the forms library.
  74
  75        The function <STRONG>field_buffer</STRONG> returns a pointer  to  the  contents  of  the
  76        given numbered buffer:
  77
  78           <STRONG>o</STRONG>   The  buffer contents always have the same length, and are padded
  79               with trailing spaces as needed to  ensure  this  length  is  the
  80               same.
  81
  82           <STRONG>o</STRONG>   The  buffer  may contain leading spaces, depending on how it was
  83               set.
  84
  85           <STRONG>o</STRONG>   The buffer contents are set with <STRONG>set_field_buffer</STRONG>, or as a  side
  86               effect of any editing operations on the corresponding field.
  87
  88           <STRONG>o</STRONG>   Editing  operations  are  based on the <EM>window</EM> which displays the
  89               field, rather than a <EM>string</EM>.  The window contains only printable
  90               characters,  and  is  filled  with  blanks.  If you want the raw
  91               data, you must write your own routine that copies the value  out
  92               of the buffer and removes the leading and trailing spaces.
  93
  94           <STRONG>o</STRONG>   Because  editing  operations change the content of the buffer to
  95               correspond to the window, you should not rely on  using  buffers
  96               for long-term storage of form data.
  97
  98        The function <STRONG>set_field_status</STRONG> sets the associated status flag of <EM>field</EM>;
  99        <STRONG>field_status</STRONG> gets the current value.  The  status  flag  is  set  to  a
 100        nonzero value whenever the field changes.
 101
 102        The  function  <STRONG>set_max_field</STRONG> sets the maximum size for a dynamic field.
 103        An argument of 0 turns off any maximum size threshold for that field.
 104
 105
 106 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
 107        The <STRONG>field_buffer</STRONG>  function  returns  NULL  on  error.   It  sets  <STRONG>errno</STRONG>
 108        according to their success:
 109
 110        <STRONG>E_OK</STRONG> The routine succeeded.
 111
 112        <STRONG>E_BAD_ARGUMENT</STRONG>
 113             Routine detected an incorrect or out-of-range argument.
 114
 115        The <STRONG>field_status</STRONG> function returns <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG>.
 116
 117        The remaining routines return one of the following:
 118
 119        <STRONG>E_OK</STRONG> The routine succeeded.
 120
 121        <STRONG>E_SYSTEM_ERROR</STRONG>
 122             System error occurred (see <STRONG>errno(3)</STRONG>).
 123
 124        <STRONG>E_BAD_ARGUMENT</STRONG>
 125             Routine detected an incorrect or out-of-range argument.
 126
 127
 128 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
 129        When  configured for wide characters, <STRONG>field_buffer</STRONG> returns a pointer to
 130        temporary  storage  (allocated  and  freed  by   the   library).    The
 131        application should not attempt to modify the data.  It will be freed on
 132        the next call to <STRONG>field_buffer</STRONG> to return the same buffer.
 133
 134
 135 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
 136        These routines emulate the System  V  forms  library.   They  were  not
 137        supported on Version 7 or BSD versions.
 138
 139        The   <STRONG>set_max_field</STRONG>   function   checks   for   an   <EM>ncurses</EM>  extension
 140        <STRONG>O_INPUT_FIELD</STRONG> which allows a dynamic field to shrink if the  new  limit
 141        is smaller than the current field size.
 142
 143
 144 </PRE><H2><a name="h2-AUTHORS">AUTHORS</a></H2><PRE>
 145        Juergen Pfeifer.  Manual pages and adaptation for new curses by Eric S.
 146        Raymond.
 147
 148
 149 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
 150        <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG> and related pages whose names  begin  "form_"  for  detailed
 151        descriptions of the entry points.
 152
 153
 154
 155 ncurses 6.4                       2023-12-16             <STRONG><A HREF="form_field_buffer.3x.html">form_field_buffer(3x)</A></STRONG>
 156 </PRE>
 157 <div class="nav">
 158 <ul>
 159 <li><a href="#h2-NAME">NAME</a></li>
 160 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
 161 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
 162 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
 163 <li><a href="#h2-NOTES">NOTES</a></li>
 164 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
 165 <li><a href="#h2-AUTHORS">AUTHORS</a></li>
 166 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
 167 </ul>
 168 </div>
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