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31 * @Id: form_fieldtype.3x,v 1.21 2020/03/28 19:06:28 tom Exp @
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43 <H1 class="no-header">form_fieldtype 3x</H1>
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>
50 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
51 <STRONG>form_fieldtype</STRONG> - define validation-field types
54 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
55 <STRONG>#include</STRONG> <STRONG><form.h></STRONG>
56 FIELDTYPE *new_fieldtype(
57 bool (* const field_check)(FIELD *, const void *),
58 bool (* const char_check)(int, const void *));
59 int free_fieldtype(FIELDTYPE *fieldtype);
60 int set_fieldtype_arg(
62 void *(* const make_arg)(va_list *),
63 void *(* const copy_arg)(const void *),
64 void (* const free_arg)(void *));
65 int set_fieldtype_choice(
67 bool (* const next_choice)(FIELD *, const void *),
68 bool (* const prev_choice)(FIELD *, const void *));
69 FIELDTYPE *link_fieldtype(FIELDTYPE *type1,
73 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
74 The function <STRONG>new_fieldtype</STRONG> creates a new field type usable for data
75 validation. You supply it with <EM>field</EM><STRONG>_</STRONG><EM>check</EM>, a predicate to check the
76 validity of an entered data string whenever the user attempts to leave
77 a field. The (FIELD *) argument is passed in so the validation predi-
78 cate can see the field's buffer, sizes and other attributes; the second
79 argument is an argument-block structure, about which more below.
81 You also supply <STRONG>new_fieldtype</STRONG> with <EM>char</EM><STRONG>_</STRONG><EM>check</EM>, a function to validate
82 input characters as they are entered; it will be passed the character
83 to be checked and a pointer to an argument-block structure.
85 The function <STRONG>free_fieldtype</STRONG> frees the space allocated for a given vali-
88 The function <STRONG>set_fieldtype_arg</STRONG> associates three storage-management
89 functions with a field type. The <EM>make</EM><STRONG>_</STRONG><EM>arg</EM> function is automatically
90 applied to the list of arguments you give <STRONG>set_field_type</STRONG> when attaching
91 validation to a field; its job is to bundle these into an allocated
92 argument-block object which can later be passed to validation predi-
93 cated. The other two hook arguments should copy and free argument-
94 block structures. They will be used by the forms-driver code. You
95 must supply the <EM>make</EM><STRONG>_</STRONG><EM>arg</EM> function, the other two are optional, you may
96 supply NULL for them. In this case it is assumed that <EM>make</EM><STRONG>_</STRONG><EM>arg</EM> does
97 not allocate memory but simply loads the argument into a single scalar
100 The function <STRONG>link_fieldtype</STRONG> creates a new field type from the two given
101 types. They are connected by an logical 'OR'.
103 The form driver requests <STRONG>REQ_NEXT_CHOICE</STRONG> and <STRONG>REQ_PREV_CHOICE</STRONG> assume
104 that the possible values of a field form an ordered set, and provide
105 the forms user with a way to move through the set. The <STRONG>set_field-</STRONG>
106 <STRONG>type_choice</STRONG> function allows forms programmers to define successor and
107 predecessor functions for the field type. These functions take the
108 field pointer and an argument-block structure as arguments.
111 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
112 The pointer-valued routines return NULL on error. They set <STRONG>errno</STRONG>
113 according to their success:
115 <STRONG>E_OK</STRONG> The routine succeeded.
117 <STRONG>E_BAD_ARGUMENT</STRONG>
118 Routine detected an incorrect or out-of-range argument.
120 <STRONG>E_SYSTEM_ERROR</STRONG>
121 System error occurred, e.g., malloc failure.
123 The integer-valued routines return one of the following codes on error:
125 <STRONG>E_OK</STRONG> The routine succeeded.
127 <STRONG>E_BAD_ARGUMENT</STRONG>
128 Routine detected an incorrect or out-of-range argument.
130 <STRONG>E_CONNECTED</STRONG>
131 The field is already connected to a form.
133 <STRONG>E_CURRENT</STRONG>
134 The field is the current field.
136 <STRONG>E_SYSTEM_ERROR</STRONG>
137 System error occurred (see <STRONG>errno(3)</STRONG>).
140 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
141 <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="form.3x.html">form(3x)</A></STRONG>.
144 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
145 The header file <STRONG><form.h></STRONG> automatically includes the header file
146 <STRONG><curses.h></STRONG>.
148 All of the <STRONG>(char</STRONG> <STRONG>*)</STRONG> arguments of these functions should actually be
149 <STRONG>(void</STRONG> <STRONG>*)</STRONG>. The type has been left uncorrected for strict compatibility
153 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
154 These routines emulate the System V forms library. They were not sup-
155 ported on Version 7 or BSD versions.
158 </PRE><H2><a name="h2-AUTHORS">AUTHORS</a></H2><PRE>
159 Juergen Pfeifer. Manual pages and adaptation for new curses by Eric S.
164 <STRONG><A HREF="form_fieldtype.3x.html">form_fieldtype(3x)</A></STRONG>
168 <li><a href="#h2-NAME">NAME</a></li>
169 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
170 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
171 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
172 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
173 <li><a href="#h2-NOTES">NOTES</a></li>
174 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
175 <li><a href="#h2-AUTHORS">AUTHORS</a></li>