.\"*************************************************************************** .\" Copyright 2018-2023,2024 Thomas E. Dickey * .\" Copyright 1998-2006,2010 Free Software Foundation, Inc. * .\" * .\" Permission is hereby granted, free of charge, to any person obtaining a * .\" copy of this software and associated documentation files (the * .\" "Software"), to deal in the Software without restriction, including * .\" without limitation the rights to use, copy, modify, merge, publish, * .\" distribute, distribute with modifications, sublicense, and/or sell * .\" copies of the Software, and to permit persons to whom the Software is * .\" furnished to do so, subject to the following conditions: * .\" * .\" The above copyright notice and this permission notice shall be included * .\" in all copies or substantial portions of the Software. * .\" * .\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * .\" OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * .\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * .\" IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, * .\" DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR * .\" OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR * .\" THE USE OR OTHER DEALINGS IN THE SOFTWARE. * .\" * .\" Except as contained in this notice, the name(s) of the above copyright * .\" holders shall not be used in advertising or otherwise to promote the * .\" sale, use or other dealings in this Software without prior written * .\" authorization. * .\"*************************************************************************** .\" .\" $Id: form_fieldtype.3x,v 1.46 2024/03/16 15:35:01 tom Exp $ .TH form_fieldtype 3X 2024-03-16 "ncurses 6.5" "Library calls" .de bP .ie n .IP \(bu 4 .el .IP \(bu 2 .. .SH NAME \fBform_fieldtype\fP \- define validation-field types .SH SYNOPSIS .nf \fB#include .PP \fBFIELDTYPE *new_fieldtype( \fBbool (* const \fIfield_check\fB)(FIELD *, const void *),\fR \fBbool (* const \fIchar_check\fB)(int, const void *));\fR \fBint free_fieldtype(FIELDTYPE *\fIfieldtype\fB);\fR .PP \fBint set_fieldtype_arg(\fP \fBFIELDTYPE *\fIfieldtype\fB,\fR \fBvoid *(* const \fImake_arg\fB)(va_list *),\fR \fBvoid *(* const \fIcopy_arg\fB)(const void *),\fR \fBvoid (* const \fIfree_arg\fB)(void *));\fR \fBint set_fieldtype_choice(\fP \fBFIELDTYPE *\fIfieldtype\fB,\fR \fBbool (* const \fInext_choice\fB)(FIELD *, const void *),\fR \fBbool (* const \fIprev_choice\fB)(FIELD *, const void *));\fR .PP \fBFIELDTYPE *link_fieldtype(FIELDTYPE *\fItype1\fB,\fR \fBFIELDTYPE *\fItype2\fB);\fR .fi .SH DESCRIPTION .SS new_fieldtype The function \fBnew_fieldtype\fP creates a new field type usable for data validation. Its parameters are function pointers: .TP 5 \fIfield_check\fP This function checks the validity of an entered data string whenever the user attempts to leave a field. It has two arguments: .RS .bP The (FIELD *) argument is passed in so the validation predicate can see the field's buffer, sizes and other attributes. .bP The second argument is an argument-block structure, about which more below. .RE .TP 5 \fIchar_check\fP This function validates input characters as they are entered. The form library passes it the character to be checked and a pointer to an argument-block structure. .SS free_fieldtype The \fBfree_fieldtype\fP function frees the space allocated for a given validation type by \fBnew_fieldtype\fP. .SS set_fieldtype_arg The function \fBset_fieldtype_arg\fP associates three storage-management functions with a field type: .TP 5 \fImake_arg\fP This function is automatically applied to the list of arguments you give \fBset_field_type\fP when attaching validation to a field. It stores the arguments in an allocated argument-block object which is used when validating input. .TP 5 \fIcopy_arg\fP This function may be used by applications to copy argument-blocks. .TP 5 \fIfree_arg\fP Frees an argument-block structure. .PP You must supply the \fImake_arg\fP function. The other two are optional: you may supply NULL for them. In this case, the form library assumes that \fImake_arg\fP does not allocate memory but simply loads the argument into a single scalar value. .SS set_fieldtype_choice The form driver requests \fBREQ_NEXT_CHOICE\fP and \fBREQ_PREV_CHOICE\fP assume that the possible values of a field form an ordered set, and provide the forms user with a way to move through the set. .PP The \fBset_fieldtype_choice\fP function allows forms programmers to define successor and predecessor functions for the field type. These functions take the field pointer and an argument-block structure as arguments. .SS link_fieldtype The function \fBlink_fieldtype\fP creates a new field type from the two given types. They are connected by an logical 'OR'. .SH RETURN VALUE The pointer-valued routines return NULL on error. They set \fBerrno\fP according to their success: .TP 5 .B E_OK The routine succeeded. .TP 5 .B E_BAD_ARGUMENT Routine detected an incorrect or out-of-range argument. .TP 5 .B E_SYSTEM_ERROR System error occurred, e.g., malloc failure. .PP The integer-valued routines return one of the following codes on error: .TP 5 .B E_OK The routine succeeded. .TP 5 .B E_BAD_ARGUMENT Routine detected an incorrect or out-of-range argument. .TP 5 .B E_CONNECTED The field is already connected to a form. .TP 5 .B E_CURRENT The field is the current field. .TP 5 .B E_SYSTEM_ERROR System error occurred (see \fBerrno\fP(3)). .SH PORTABILITY These routines emulate the System V forms library. They were not supported on Version 7 or BSD versions. .SH AUTHORS Juergen Pfeifer. Manual pages and adaptation for new curses by Eric S. Raymond. .SH SEE ALSO \fB\%curses\fP(3X), \fB\%form\fP(3X), \fB\%form_field_validation\fP(3X)