+'\" t
.\"***************************************************************************
-.\" Copyright (c) 1998-2010,2015 Free Software Foundation, Inc. *
+.\" Copyright 2018-2022,2023 Thomas E. Dickey *
+.\" Copyright 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 1.25 2015/12/05 21:06:26 tom Exp $
-.TH form_driver 3X ""
+.\" $Id: form_driver.3x,v 1.54 2023/12/23 16:08:25 tom Exp $
+.TH form_driver 3X 2023-12-23 "ncurses 6.4" "Library calls"
.de bP
-.IP \(bu 4
+.ie n .IP \(bu 4
+.el .IP \(bu 2
..
.SH NAME
-\fBform_driver\fR,
-\fBform_driver_w\fR \- command-processing loop of the form system
+\fBform_driver\fP,
+\fBform_driver_w\fP \-
+command-processing loop of the form system
.SH SYNOPSIS
-\fB#include <form.h>\fR
-.br
-\fBint form_driver(FORM *\fP\fIform\fP\fB, int \fP\fIc\fP\fB);\fP
-.br
-\fBint form_driver_w(FORM *\fP\fIform\fP\fB, int \fP\fIc\fP\fB, wchar_t \fP\fIwch\fP\fB);\fP
-.br
+.nf
+\fB#include <form.h>
+.PP
+\fBint form_driver(FORM *\fIform\fP, int \fIc\fP);
+\fBint form_driver_w(FORM *\fIform\fP, int \fIc\fP, wchar_t \fIwch\fP);
+.fi
.SH DESCRIPTION
.SS form_driver
Once a form has been posted (displayed), you should funnel input events to it
-through \fBform_driver\fR. This routine has three major input cases:
+through \fBform_driver\fP. This routine has three major input cases:
.bP
The input is a form navigation request.
Navigation request codes are constants defined in \fB<form.h>\fP,
-which are distinct from the key- and character codes returned by \fBwgetch\fP(3X).
+which are distinct from the key- and character codes returned
+by \fBwgetch\fP(3X).
.bP
The input is a printable character.
Printable characters (which must be positive, less than 256) are
.bP
The input is the KEY_MOUSE special key associated with an mouse event.
.SS form_driver_w
-.PP
This extension simplifies the use of the forms library using wide characters.
The input is either a key code (a request) or a wide character
returned by \fBget_wch\fP(3X).
The type must be passed as well,
to enable the library to determine whether the parameter
is a wide character or a request.
-.SS Form-driver requests
-.PP
+.SS "Form Driver Requests"
The form driver requests are as follows:
+.PP
.TS
l l
-_ _ _
+_ _
l l.
-\fIName\fR \fIDescription\fR
+\fBName\fP \fBDescription\fP
REQ_BEG_FIELD Move to the beginning of the field.
REQ_BEG_LINE Move to the beginning of the line.
REQ_CLR_EOF Clear to end of field from cursor.
.TE
.PP
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
+in the current position in the current field.
+If it is one of the forms
requests listed above, that request is executed.
-.SS Mouse handling
+.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
+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"
If the second argument is the KEY_MOUSE special key, the associated
mouse event is translated into one of the above pre-defined requests.
Currently only clicks in the user window (e.g., inside the form display
.bP
If you double-click a field,
the form cursor is positioned to that field
-and \fBE_UNKNOWN_COMMAND\fR is returned.
+and \fBE_UNKNOWN_COMMAND\fP is returned.
This return value makes sense,
because a double click usually means that an field-specific action should
be returned.
application specific command should be executed.
.bP
If a translation
-into a request was done, \fBform_driver\fR returns the result of this request.
+into a request was done, \fBform_driver\fP returns the result of this request.
.RE
.PP
-If you clicked outside the user window or the mouse event could not be translated
-into a form request an \fBE_REQUEST_DENIED\fR is returned.
-.SS Application-defined commands
-.PP
+If you clicked outside the user window
+or the mouse event could not be translated
+into a form request an \fBE_REQUEST_DENIED\fP is returned.
+.SS "Application-defined Commands"
If the second argument is neither printable nor one of the above
pre-defined form requests, the driver assumes it is an application-specific
-command and returns \fBE_UNKNOWN_COMMAND\fR. Application-defined commands
-should be defined relative to \fBMAX_COMMAND\fR, the maximum value of these
+command and returns \fBE_UNKNOWN_COMMAND\fP. Application-defined commands
+should be defined relative to \fBMAX_COMMAND\fP, the maximum value of these
pre-defined requests.
.SH RETURN VALUE
-\fBform_driver\fR returns one of the following error codes:
+\fBform_driver\fP returns one of the following error codes:
.TP 5
.B E_OK
The routine succeeded.
.B E_INVALID_FIELD
Contents of field is invalid.
.TP 5
+.B E_NOT_CONNECTED
+No fields are connected to the form.
+.TP 5
.B E_REQUEST_DENIED
The form driver could not process the request.
.TP 5
.B E_SYSTEM_ERROR
-System error occurred (see \fBerrno\fR).
+System error occurred (see \fBerrno\fP(3)).
.TP 5
.B E_UNKNOWN_COMMAND
The form driver code saw an unknown request code.
-.
-.SH SEE ALSO
-\fBcurses\fR(3X),
-\fBform\fR(3X),
-\fBform_variables\fR(3X),
-\fBgetch\fR(3X).
-.SH NOTES
-The header file \fB<form.h>\fR automatically includes the header files
-\fB<curses.h>\fR.
.SH PORTABILITY
-These routines emulate the System V forms library. They were not supported on
+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.
+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_fieldtype\fP(3X),
+\fB\%form_field_buffer\fP(3X),
+\fB\%form_field_validation\fP(3X),
+\fB\%form_variables\fP(3X),
+\fB\%getch\fP(3X)
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