1form_fieldtype(3X) form_fieldtype(3X)
2
6 form_fieldtype - define validation-field types
7
9 #include <form.h>
10 FIELDTYPE *new_fieldtype(
12 bool (* const field_check)(FIELD *, const void *),
13 bool (* const char_check)(int, const void *));
14 int free_fieldtype(FIELDTYPE *fieldtype);
15 int set_fieldtype_arg(
17 FIELDTYPE *fieldtype,
18 void *(* const make_arg)(va_list *),
19 void *(* const copy_arg)(const void *),
20 void (* const free_arg)(void *));
21 int set_fieldtype_choice(
22 FIELDTYPE *fieldtype,
23 bool (* const next_choice)(FIELD *, const void *),
24 bool (* const prev_choice)(FIELD *, const void *));
25 FIELDTYPE *link_fieldtype(FIELDTYPE *type1,
27 FIELDTYPE *type2);
28
30 new_fieldtype
31 The function new_fieldtype creates a new field type usable for data
32 validation. Its parameters are function pointers:
33 field_check
35 This function checks the validity of an entered data string when‐
36 ever the user attempts to leave a field. It has two arguments:
37 • The (FIELD *) argument is passed in so the validation predi‐
39 cate can see the field's buffer, sizes and other attributes.
40 • The second argument is an argument-block structure, about
42 which more below.
43 char_check
45 This function validates input characters as they are entered. The
46 form library passes it the character to be checked and a pointer
47 to an argument-block structure.
48 free_fieldtype
50 The free_fieldtype function frees the space allocated for a given vali‐
51 dation type by new_fieldtype.
52 set_fieldtype_arg
54 The function set_fieldtype_arg associates three storage-management
55 functions with a field type:
56 make_arg
58 This function is automatically applied to the list of arguments
59 you give set_field_type when attaching validation to a field. It
60 stores the arguments in an allocated argument-block object which
61 is used when validating input.
62 copy_arg
64 This function may be used by applications to copy argument-blocks.
65 free_arg
67 Frees an argument-block structure.
68 You must supply the make_arg function. The other two are optional: you
70 may supply NULL for them. In this case, the form library assumes that
71 make_arg does not allocate memory but simply loads the argument into a
72 single scalar value.
73 set_fieldtype_choice
75 The form driver requests REQ_NEXT_CHOICE and REQ_PREV_CHOICE assume
76 that the possible values of a field form an ordered set, and provide
77 the forms user with a way to move through the set.
78 The set_fieldtype_choice function allows forms programmers to define
80 successor and predecessor functions for the field type. These func‐
81 tions take the field pointer and an argument-block structure as argu‐
82 ments.
83 link_fieldtype
85 The function link_fieldtype creates a new field type from the two given
86 types. They are connected by an logical 'OR'.
87
89 The pointer-valued routines return NULL on error. They set errno ac‐
90 cording to their success:
91 E_OK The routine succeeded.
93 E_BAD_ARGUMENT
95 Routine detected an incorrect or out-of-range argument.
96 E_SYSTEM_ERROR
98 System error occurred, e.g., malloc failure.
99 The integer-valued routines return one of the following codes on error:
101 E_OK The routine succeeded.
103 E_BAD_ARGUMENT
105 Routine detected an incorrect or out-of-range argument.
106 E_CONNECTED
108 The field is already connected to a form.
109 E_CURRENT
111 The field is the current field.
112 E_SYSTEM_ERROR
114 System error occurred (see errno(3)).
115
117 curses(3X), form(3X), form_field_validation(3X).
118
120 The header file <form.h> automatically includes the header file
121 <curses.h>.
122
124 These routines emulate the System V forms library. They were not sup‐
125 ported on Version 7 or BSD versions.
126
128 Juergen Pfeifer. Manual pages and adaptation for new curses by Eric S.
129 Raymond.
130 form_fieldtype(3X)