.\"***************************************************************************
-.\" Copyright (c) 1998-2010,2015 Free Software Foundation, Inc. *
+.\" Copyright (c) 1998-2016,2017 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 *
.\" authorization. *
.\"***************************************************************************
.\"
-.\" $Id: form_driver.3x,v 1.24 2015/08/02 18:21:11 tom Exp $
+.\" $Id: form_driver.3x,v 1.28 2017/11/18 23:47:37 tom Exp $
.TH form_driver 3X ""
.de bP
-.IP \(bu 4
+.ie n .IP \(bu 4
+.el .IP \(bu 2
..
.SH NAME
-\fBform_driver\fR \- command-processing loop of the form system
+\fBform_driver\fR,
+\fBform_driver_w\fR \- command-processing loop of the form system
.SH SYNOPSIS
\fB#include <form.h>\fR
.br
The form driver requests are as follows:
.TS
l l
-_ _ _
+_ _
l l.
\fIName\fR \fIDescription\fR
REQ_BEG_FIELD Move to the beginning of the field.
If the second argument is a printable character, the driver places it
in the current position in the current field. If it is one of the forms
requests listed above, that request is executed.
+.SS Field validation
+The form library makes updates to the window associated with form fields rather than
+directly to the field buffers.
+.PP
+The form driver provides low-level control over updates to the form fields.
+The form driver also provides for validating modified fields to ensure that the contents
+meet whatever constraints an application may attach using \fBset_field_type\fP.
+.PP
+.PP
+You can validate a field without making any changes to it using
+\fBREQ_VALIDATION\fP.
+The form driver also validates a field in these cases:
+.bP
+a call to \fBset_current_field\fP attempts to move to a different field.
+.bP
+a call to \fBset_current_page\fP attempts to move to a different page of the form.
+.bP
+a request attempts to move to a different field.
+.bP
+a request attempts to move to a different page of the form.
+.PP
+In each case, the move fails if the field is invalid.
+.PP
+If the modified field is valid, the form driver copies the modified
+data from the window associated with the field
+to the field buffer.
.SS Mouse handling
.PP
If the second argument is the KEY_MOUSE special key, the associated
.SH SEE ALSO
\fBcurses\fR(3X),
\fBform\fR(3X),
+\fBform_field_buffer\fR(3X),
+\fBform_field_validation\fR(3X),
+\fBform_fieldtype\fR(3X),
\fBform_variables\fR(3X),
\fBgetch\fR(3X).
.SH NOTES