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  43 <H1 class="no-header">form_fieldtype 3x</H1>
  44 <PRE>
  45 <STRONG><A HREF="form_fieldtype.3x.html">form_fieldtype(3x)</A></STRONG>                                          <STRONG><A HREF="form_fieldtype.3x.html">form_fieldtype(3x)</A></STRONG>
  46
  47
  48
  49
  50 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
  51        <STRONG>form_fieldtype</STRONG> - define validation-field types
  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>FIELDTYPE</STRONG> <STRONG>*new_fieldtype(</STRONG>
  58            <STRONG>bool</STRONG> <STRONG>(*</STRONG> <STRONG>const</STRONG> <EM>field</EM><STRONG>_</STRONG><EM>check</EM><STRONG>)(FIELD</STRONG> <STRONG>*,</STRONG> <STRONG>const</STRONG> <STRONG>void</STRONG> <STRONG>*),</STRONG>
  59            <STRONG>bool</STRONG> <STRONG>(*</STRONG> <STRONG>const</STRONG> <EM>char</EM><STRONG>_</STRONG><EM>check</EM><STRONG>)(int,</STRONG> <STRONG>const</STRONG> <STRONG>void</STRONG> <STRONG>*));</STRONG>
  60        <STRONG>int</STRONG> <STRONG>free_fieldtype(FIELDTYPE</STRONG> <STRONG>*</STRONG><EM>fieldtype</EM><STRONG>);</STRONG>
  61
  62        <STRONG>int</STRONG> <STRONG>set_fieldtype_arg(</STRONG>
  63            <STRONG>FIELDTYPE</STRONG> <STRONG>*</STRONG><EM>fieldtype</EM><STRONG>,</STRONG>
  64            <STRONG>void</STRONG> <STRONG>*(*</STRONG> <STRONG>const</STRONG> <EM>make</EM><STRONG>_</STRONG><EM>arg</EM><STRONG>)(va_list</STRONG> <STRONG>*),</STRONG>
  65            <STRONG>void</STRONG> <STRONG>*(*</STRONG> <STRONG>const</STRONG> <EM>copy</EM><STRONG>_</STRONG><EM>arg</EM><STRONG>)(const</STRONG> <STRONG>void</STRONG> <STRONG>*),</STRONG>
  66            <STRONG>void</STRONG>  <STRONG>(*</STRONG> <STRONG>const</STRONG> <EM>free</EM><STRONG>_</STRONG><EM>arg</EM><STRONG>)(void</STRONG> <STRONG>*));</STRONG>
  67        <STRONG>int</STRONG> <STRONG>set_fieldtype_choice(</STRONG>
  68            <STRONG>FIELDTYPE</STRONG> <STRONG>*</STRONG><EM>fieldtype</EM><STRONG>,</STRONG>
  69            <STRONG>bool</STRONG> <STRONG>(*</STRONG> <STRONG>const</STRONG> <EM>next</EM><STRONG>_</STRONG><EM>choice</EM><STRONG>)(FIELD</STRONG> <STRONG>*,</STRONG> <STRONG>const</STRONG> <STRONG>void</STRONG> <STRONG>*),</STRONG>
  70            <STRONG>bool</STRONG> <STRONG>(*</STRONG> <STRONG>const</STRONG> <EM>prev</EM><STRONG>_</STRONG><EM>choice</EM><STRONG>)(FIELD</STRONG> <STRONG>*,</STRONG> <STRONG>const</STRONG> <STRONG>void</STRONG> <STRONG>*));</STRONG>
  71
  72        <STRONG>FIELDTYPE</STRONG> <STRONG>*link_fieldtype(FIELDTYPE</STRONG> <STRONG>*</STRONG><EM>type1</EM><STRONG>,</STRONG>
  73                                  <STRONG>FIELDTYPE</STRONG> <STRONG>*</STRONG><EM>type2</EM><STRONG>);</STRONG>
  74
  75
  76 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
  77        The  function  <STRONG>new_fieldtype</STRONG>  creates  a new field type usable for data
  78        validation.  You supply it with <EM>field</EM><STRONG>_</STRONG><EM>check</EM>, a predicate to  check  the
  79        validity  of an entered data string whenever the user attempts to leave
  80        a field.  The (FIELD *) argument is passed in so the validation  predi-
  81        cate can see the field's buffer, sizes and other attributes; the second
  82        argument is an argument-block structure, about which more below.
  83
  84        You also supply <STRONG>new_fieldtype</STRONG> with <EM>char</EM><STRONG>_</STRONG><EM>check</EM>, a function  to  validate
  85        input  characters  as they are entered; it will be passed the character
  86        to be checked and a pointer to an argument-block structure.
  87
  88        The function <STRONG>free_fieldtype</STRONG> frees the space allocated for a given vali-
  89        dation type.
  90
  91        The  function  <STRONG>set_fieldtype_arg</STRONG>  associates  three  storage-management
  92        functions with a field type.  The <EM>make</EM><STRONG>_</STRONG><EM>arg</EM>  function  is  automatically
  93        applied to the list of arguments you give <STRONG>set_field_type</STRONG> when attaching
  94        validation to a field; its job is to bundle  these  into  an  allocated
  95        argument-block  object  which  can later be passed to validation predi-
  96        cated.  The other two hook arguments should  copy  and  free  argument-
  97        block  structures.   They  will  be used by the forms-driver code.  You
  98        must supply the <EM>make</EM><STRONG>_</STRONG><EM>arg</EM> function, the other two are optional, you  may
  99        supply  NULL  for  them.  In this case it is assumed that <EM>make</EM><STRONG>_</STRONG><EM>arg</EM> does
 100        not allocate memory but simply loads the argument into a single  scalar
 101        value.
 102
 103        The function <STRONG>link_fieldtype</STRONG> creates a new field type from the two given
 104        types.  They are connected by an logical 'OR'.
 105
 106        The form driver requests  <STRONG>REQ_NEXT_CHOICE</STRONG>  and  <STRONG>REQ_PREV_CHOICE</STRONG>  assume
 107        that  the  possible  values of a field form an ordered set, and provide
 108        the forms user with a way to move  through  the  set.   The  <STRONG>set_field-</STRONG>
 109        <STRONG>type_choice</STRONG>  function  allows forms programmers to define successor and
 110        predecessor functions for the field type.   These  functions  take  the
 111        field pointer and an argument-block structure as arguments.
 112
 113
 114 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
 115        The  pointer-valued  routines  return  NULL  on  error.  They set <STRONG>errno</STRONG>
 116        according to their success:
 117
 118        <STRONG>E_OK</STRONG> The routine succeeded.
 119
 120        <STRONG>E_BAD_ARGUMENT</STRONG>
 121             Routine detected an incorrect or out-of-range argument.
 122
 123        <STRONG>E_SYSTEM_ERROR</STRONG>
 124             System error occurred, e.g., malloc failure.
 125
 126        The integer-valued routines return one of the following codes on error:
 127
 128        <STRONG>E_OK</STRONG> The routine succeeded.
 129
 130        <STRONG>E_BAD_ARGUMENT</STRONG>
 131             Routine detected an incorrect or out-of-range argument.
 132
 133        <STRONG>E_CONNECTED</STRONG>
 134             The field is already connected to a form.
 135
 136        <STRONG>E_CURRENT</STRONG>
 137             The field is the current field.
 138
 139        <STRONG>E_SYSTEM_ERROR</STRONG>
 140             System error occurred (see <STRONG>errno(3)</STRONG>).
 141
 142
 143 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
 144        <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="form.3x.html">form(3x)</A></STRONG>.
 145
 146
 147 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
 148        The  header  file  <STRONG>&lt;form.h&gt;</STRONG>  automatically  includes  the  header  file
 149        <STRONG>&lt;curses.h&gt;</STRONG>.
 150
 151        All  of  the  <STRONG>(char</STRONG>  <STRONG>*)</STRONG> arguments of these functions should actually be
 152        <STRONG>(void</STRONG> <STRONG>*)</STRONG>.  The type has been left uncorrected for strict  compatibility
 153        with System V.
 154
 155
 156 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
 157        These  routines emulate the System V forms library.  They were not sup-
 158        ported on Version 7 or BSD versions.
 159
 160
 161 </PRE><H2><a name="h2-AUTHORS">AUTHORS</a></H2><PRE>
 162        Juergen Pfeifer.  Manual pages and adaptation for new curses by Eric S.
 163        Raymond.
 164
 165
 166
 167                                                             <STRONG><A HREF="form_fieldtype.3x.html">form_fieldtype(3x)</A></STRONG>
 168 </PRE>
 169 <div class="nav">
 170 <ul>
 171 <li><a href="#h2-NAME">NAME</a></li>
 172 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
 173 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
 174 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
 175 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
 176 <li><a href="#h2-NOTES">NOTES</a></li>
 177 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
 178 <li><a href="#h2-AUTHORS">AUTHORS</a></li>
 179 </ul>
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