ncurses 6.2 - patch 20210116
[ncurses.git] / doc / html / man / form_fieldtype.3x.html
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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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