4 \fBform_fieldtype\fR - define validation-field types
6 \fB#include <form.h>\fR
8 FIELDTYPE *new_fieldtype(
9 bool (* const field_check)(FIELD *, const void *),
10 bool (* const char_check)(int, const void *));
12 int free_fieldtype(FIELDTYPE *fieldtype);
14 int set_fieldtype_arg(
16 void *(* const make_arg)(va_list *),
17 void *(* const copy_arg)(const void *),
18 void (* const free_arg)(void *));
20 int set_fieldtype_choice(
22 bool (* const next_choice)(FIELD *, const void *),
23 bool (* const prev_choice)(FIELD *, const void *));
25 FIELDTYPE *link_fieldtype(FIELDTYPE *type1,
29 The function \fBnew_fieldtype\fR creates a new field type usable for data
30 validation. You supply it with \fIfield_check\fR, a predicate to check the
31 validity of an entered data string whenever the user attempt to leave a field.
32 The (FIELD *) argument is passed in so the validation predicate can see the
33 field's buffer, sizes and other attributes; the second argument is an
34 argument-block structure, about which more below.
36 You also supply \fBnew_fieldtype\fR with \fIchar_check\fR,
37 a function to validate input characters as they are entered; it will be passed
38 the character to be checked and a pointer to an argument-block structure.
40 The function \fBfree_fieldtype\fR frees the space allocated for a given
43 The function \fBset_fieldtype\fR associates three storage-management functions
44 with a field type. The \fImak_arg\fR function is automatically applied to the
45 list of arguments you give \fBset_field_type\fR when attaching validation
46 to a field; its job is to bundle these into an allocated argument-block
47 object which can later be passed to validation predicated. The other two
48 hook arguments should copy and free argument-block structures. They will
49 be used by the forms-driver code. You must supply the \fImak_arg\fR function,
50 the other two are optional, you may supply NULL for them. In this case it
51 is assumed, that \fImak_arg\fR doesn't allocate memory but simply loads the
52 argument into a single scalar value.
54 The form driver requests \fBREQ_NEXT_CHOICE\fR and \fBREQ_PREV_CHOICE\fR assume
55 that the possible values of a field form an ordered set, and provide the forms
56 user with a way to move through the set. The \fBset_fieldtype_choice\fR
57 function allows forms programmers to define successor and predecessor functions
58 for the field type. These functions take the field pointer and an
59 argument-block structure as arguments.
61 The pointer-valued routines return NULL on error.
63 The integer-valued routines return one of the following codes on
67 The routine succeeded.
70 System error occurred (see \fBerrno\fR).
73 Routine detected an incorrect or out-of-range argument.
76 The field is already connected to a form.
78 \fBcurses\fR(3X), \fBform\fR(3X).
80 The header file \fB<form.h>\fR automatically includes the header file
83 All of the \fB(char *)\fR arguments of these functions should actually be
84 \fB(void *)\fR. The type has been left uncorrected for strict compatibility
87 These routines emulate the System V forms library. They were not supported on
88 Version 7 or BSD versions.
90 Juergen Pfeifer. Manual pages and adaptation for new curses by Eric
93 .\"# The following sets edit modes for GNU EMACS