1form_field_validation(3X) form_field_validation(3X)
2
6 form_field_validation - data type validation for fields
7
9 #include <form.h>
10 void *field_arg(const FIELD *field);
12 FIELDTYPE *field_type(const FIELD *field);
13 int set_field_type(FIELD *field, FIELDTYPE *type, ...);
14 /* predefined field types */
16 FIELDTYPE *TYPE_ALNUM;
17 FIELDTYPE *TYPE_ALPHA;
18 FIELDTYPE *TYPE_ENUM;
19 FIELDTYPE *TYPE_INTEGER;
20 FIELDTYPE *TYPE_NUMERIC;
21 FIELDTYPE *TYPE_REGEXP;
22 FIELDTYPE *TYPE_IPV4;
23
25 By default, no validation is done on form fields. You can associate a
26 form with with a field type, making the form library validate input.
27 field_arg
29 Returns a pointer to the field's argument block. The argument block is
30 an opaque structure containing a copy of the arguments provided in a
31 set_field_type call.
32 field_type
34 Returns a pointer to the field type associated with the form field,
35 i.e., by calling set_field_type.
36 set_field_type
38 The function set_field_type associates a field type with a given form
39 field. This is the type checked by validation functions. Most field
40 types are configurable, via arguments which the caller provides when
41 calling set_field_type.
42 Several field types are predefined by the form library.
44 Predefined types
46 It is possible to set up new programmer-defined field types. Field
47 types are implemented via the FIELDTYPE data structure, which contains
48 several pointers to functions.
49 See the form_fieldtype(3X) manual page, which describes functions which
51 can be used to construct a field-type dynamically.
52 The predefined types are as follows:
54 TYPE_ALNUM
56 Alphanumeric data. Required parameter:
57 • a third int argument, a minimum field width.
59 TYPE_ALPHA
61 Character data. Required parameter:
62 • a third int argument, a minimum field width.
64 TYPE_ENUM
66 Accept one of a specified set of strings. Required parameters:
67 • a third (char **) argument pointing to a string list;
69 • a fourth int flag argument to enable case-sensitivity;
71 • a fifth int flag argument specifying whether a partial match
73 must be a unique one. If this flag is off, a prefix matches
74 the first of any set of more than one list elements with that
75 prefix.
76 The library copies the string list, so you may use a list that
78 lives in automatic variables on the stack.
79 TYPE_INTEGER
81 Integer data, parsable to an integer by atoi(3). Required parame‐
82 ters:
83 • a third int argument controlling the precision,
85 • a fourth long argument constraining minimum value,
87 • a fifth long constraining maximum value. If the maximum value
89 is less than or equal to the minimum value, the range is sim‐
90 ply ignored.
91 On return, the field buffer is formatted according to the printf
93 format specification “.*ld”, where the “*” is replaced by the pre‐
94 cision argument.
95 For details of the precision handling see printf(3).
97 TYPE_NUMERIC
99 Numeric data (may have a decimal-point part). Required parame‐
100 ters:
101 • a third int argument controlling the precision,
103 • a fourth double argument constraining minimum value,
105 • and a fifth double constraining maximum value. If your system
107 supports locales, the decimal point character must be the one
108 specified by your locale. If the maximum value is less than
109 or equal to the minimum value, the range is simply ignored.
110 On return, the field buffer is formatted according to the printf
112 format specification “.*f”, where the “*” is replaced by the pre‐
113 cision argument.
114 For details of the precision handling see printf(3).
116 TYPE_REGEXP
118 Regular expression data. Required parameter:
119 • a third argument, a regular expression (char *) string. The
121 data is valid if the regular expression matches it.
122 Regular expressions are in the format of regcomp and regexec.
124 The regular expression must match the whole field. If you have
126 for example, an eight character wide field, a regular expression
127 "^[0-9]*$" always means that you have to fill all eight positions
128 with digits. If you want to allow fewer digits, you may use for
129 example "^[0-9]* *$" which is good for trailing spaces (up to an
130 empty field), or "^ *[0-9]* *$" which is good for leading and
131 trailing spaces around the digits.
132 TYPE_IPV4
134 An Internet Protocol Version 4 address. Required parameter:
135 • none
137 The form library checks whether or not the buffer has the form
139 a.b.c.d, where a, b, c, and d are numbers in the range 0 to 255.
140 Trailing blanks in the buffer are ignored. The address itself is
141 not validated.
142 This is an ncurses extension; this field type may not be available
144 in other curses implementations.
145
147 The functions field_type and field_arg return NULL on error. The func‐
148 tion set_field_type returns one of the following:
149 E_OK The routine succeeded.
151 E_SYSTEM_ERROR
153 System error occurred (see errno(3)).
154
156 curses(3X), form(3X), form_fieldtype(3X), form_variables(3X).
157
159 The header file <form.h> automatically includes the header file
160 <curses.h>.
161
163 These routines emulate the System V forms library. They were not sup‐
164 ported on Version 7 or BSD versions.
165
167 Juergen Pfeifer. Manual pages and adaptation for new curses by Eric S.
168 Raymond.
169 form_field_validation(3X)