2 .\"***************************************************************************
3 .\" Copyright 2018-2019,2020 Thomas E. Dickey *
4 .\" Copyright 1998-2006,2010 Free Software Foundation, Inc. *
6 .\" Permission is hereby granted, free of charge, to any person obtaining a *
7 .\" copy of this software and associated documentation files (the *
8 .\" "Software"), to deal in the Software without restriction, including *
9 .\" without limitation the rights to use, copy, modify, merge, publish, *
10 .\" distribute, distribute with modifications, sublicense, and/or sell *
11 .\" copies of the Software, and to permit persons to whom the Software is *
12 .\" furnished to do so, subject to the following conditions: *
14 .\" The above copyright notice and this permission notice shall be included *
15 .\" in all copies or substantial portions of the Software. *
17 .\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
18 .\" OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
19 .\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. *
20 .\" IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, *
21 .\" DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR *
22 .\" OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR *
23 .\" THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
25 .\" Except as contained in this notice, the name(s) of the above copyright *
26 .\" holders shall not be used in advertising or otherwise to promote the *
27 .\" sale, use or other dealings in this Software without prior written *
29 .\"***************************************************************************
31 .\" $Id: form_fieldtype.3x,v 1.23 2020/10/24 09:05:17 tom Exp $
32 .TH form_fieldtype 3X ""
34 \fBform_fieldtype\fR \- define validation-field types
36 \fB#include <form.h>\fR
38 \fBFIELDTYPE *new_fieldtype(\fP
39 \fBbool (* const \fP\fIfield_check\fP\fB)(FIELD *, const void *),\fP
40 \fBbool (* const \fP\fIchar_check\fP\fB)(int, const void *));\fP
42 \fBint free_fieldtype(FIELDTYPE *\fP\fIfieldtype\fP\fB);\fP
44 \fBint set_fieldtype_arg(\fP
45 \fBFIELDTYPE *\fP\fIfieldtype\fP\fB,\fP
46 \fBvoid *(* const \fP\fImake_arg\fP\fB)(va_list *),\fP
47 \fBvoid *(* const \fP\fIcopy_arg\fP\fB)(const void *),\fP
48 \fBvoid (* const \fP\fIfree_arg\fP\fB)(void *));\fP
50 \fBint set_fieldtype_choice(\fP
51 \fBFIELDTYPE *\fP\fIfieldtype\fP\fB,\fP
52 \fBbool (* const \fP\fInext_choice\fP\fB)(FIELD *, const void *),\fP
53 \fBbool (* const \fP\fIprev_choice\fP\fB)(FIELD *, const void *));\fP
55 \fBFIELDTYPE *link_fieldtype(FIELDTYPE *\fP\fItype1\fP\fB,\fP
56 \fBFIELDTYPE *\fP\fItype2\fP\fB);\fP
58 The function \fBnew_fieldtype\fR creates a new field type usable for data
60 You supply it with \fIfield_check\fR, a predicate to check the
61 validity of an entered data string whenever the user attempts to leave a field.
62 The (FIELD *) argument is passed in so the validation predicate can see the
63 field's buffer, sizes and other attributes; the second argument is an
64 argument-block structure, about which more below.
66 You also supply \fBnew_fieldtype\fR with \fIchar_check\fR,
67 a function to validate input characters as they are entered; it will be passed
68 the character to be checked and a pointer to an argument-block structure.
70 The function \fBfree_fieldtype\fR frees the space allocated for a given
73 The function \fBset_fieldtype_arg\fR associates
74 three storage-management functions with a field type.
75 The \fImake_arg\fR function is automatically applied to the
76 list of arguments you give \fBset_field_type\fR when attaching validation
77 to a field; its job is to bundle these into an allocated argument-block
78 object which can later be passed to validation predicated.
79 The other two hook arguments should copy and free argument-block structures.
80 They will be used by the forms-driver code.
81 You must supply the \fImake_arg\fR function,
82 the other two are optional, you may supply NULL for them.
83 In this case it is assumed
84 that \fImake_arg\fR does not allocate memory but simply loads the
85 argument into a single scalar value.
87 The function \fBlink_fieldtype\fR creates
88 a new field type from the two given types.
89 They are connected by an logical 'OR'.
91 The form driver requests \fBREQ_NEXT_CHOICE\fR and \fBREQ_PREV_CHOICE\fR assume
92 that the possible values of a field form an ordered set, and provide the forms
93 user with a way to move through the set.
94 The \fBset_fieldtype_choice\fR
95 function allows forms programmers to define successor and predecessor functions
97 These functions take the field pointer and an
98 argument-block structure as arguments.
100 The pointer-valued routines return NULL on error.
101 They set \fBerrno\fP according to their success:
104 The routine succeeded.
107 Routine detected an incorrect or out-of-range argument.
110 System error occurred, e.g., malloc failure.
112 The integer-valued routines return one of the following codes on
116 The routine succeeded.
119 Routine detected an incorrect or out-of-range argument.
122 The field is already connected to a form.
125 The field is the current field.
128 System error occurred (see \fBerrno\fR(3)).
130 \fBcurses\fR(3X), \fBform\fR(3X).
132 The header file \fB<form.h>\fR automatically includes the header file
135 All of the \fB(char *)\fR arguments of these functions should actually be
136 \fB(void *)\fR. The type has been left uncorrected for strict compatibility
139 These routines emulate the System V forms library.
140 They were not supported on
141 Version 7 or BSD versions.
144 Manual pages and adaptation for new curses by Eric S. Raymond.