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The I<FD_CMDLOG>, I<FD_FSELECTOR>, I<FL_EditKeymap>, I<FL_FORM>, I<FL_IOPT>
and I<FL_OBJECT> data structures have been defined as Perl objects 
(within the B<X11::Xforms> package). Therefore, the values of most fields in each 
structure can be directly read. In addition, all fields within the 
I<FL_IOPT> structure, and many of the I<FL_FORM> and I<FL_OBJECT> structures, 
can be updated too. 

The syntax to read a field is:

C<	$value = $struct_ref-E<gt>field_name;> 

and to write a writable field is

C<	$oldval = $struct_ref-E<gt>field_name(new_value);>

where '$struct_ref' is the 'blessed' Perl object returned by such 
functions as B<fl_get_fselector_fdstruct>, B<fl_get_command_log_fdstruct>,
B<fl_[create/add]_[object_type]> and B<fl_bgn_form>. In fact the return
value of any function that, in Xforms itself, returns one of the above
structures, can be used as the '$struct_ref' part of a field access.

The available fields in each structure, together with an indication 
of whether each field is read-only (ro) or read-write (rw), are
as follows:

=over 4

=item FD_CMDLOG

All fields are available read-only. However, since
the fields themselves contain FL_FORM or FL_OBJECT 
structures, the fields within those structures can
be accessed as below.

=item FD_FSELECTOR

All fields are available read-only. However, since
the fields themselves contain FL_FORM or FL_OBJECT 
structures, the fields within those structures can
be accessed as below.

=item FL_FORM

 compress_mask     rw
 deactivated       rw
 evmask            rw
 fdui              rw
 first             ro
 focusobj          ro
 frozen            rw
 h                 rw
 has_auto          rw
 hotx              rw
 hoty              rw
 icon_mask         rw
 icon_pixmap       rw
 label             rw
 last              ro
 prop              rw
 top               rw
 u_cdata           rw     
 u_ldata           rw    
 u_vdata           rw    
 use_pixmap        rw
 visible           rw
 vmode             rw
 w                 rw
 window            ro
 wm_border         rw
 x                 rw
 y                 rw

Be warned that the u_cdata field is treated exactly as 
defined - as a character string - and not as a void pointer. Therefore
when writing its value from Perl, be sure to provide a valid character 
string.

=item FL_OBJECT

 active            rw
 align             rw
 argument          rw
 automatic         rw
 belowmouse        rw
 boxtype           rw
 bw                rw
 child             ro
 click_timeout     rw
 clip              rw
 col1              rw
 col2              rw
 double_buffer     rw
 focus             rw
 form              ro
 h                 rw
 input             rw
 label             rw
 lcol              rw
 lsize             rw
 lstyle            rw
 nc                ro
 next              ro
 nwgravity         rw
 objclass          rw
 parent            ro
 prev              ro
 pushed            rw
 radio             rw
 redraw            rw
 resize            rw
 segravity         rw
 type              rw
 u_cdata           rw
 u_ldata           rw    
 u_vdata           rw
 use_pixmap        rw
 visible           rw
 w                 rw
 wantkey           rw
 window            ro
      (virtual field equivalent to $obj->form->window)
 x                 rw
 y                 rw

Be warned that the u_cdata field is treated exactly as 
defined - as a character string - and not as a void pointer. Therefore
when writing its value from Perl, be sure to provide a valid character 
string.

=item FL_IOPT

All fields in this structure are available as read-
write fields. In addition, there is an extra method
provided that returns a reference to a blank FL_IOPT 
object:

C<	$iopt = X11::Xforms::FLOpt-E<gt>new;>

Alternatively, a populated FL_IOPT object can be 
obtained using the B<fl_get_defaults> function.

=item FL_EditKeymap

This structure is used with the B<fl_set_input_editkeymap>
function. All fields in this structure are available 
as read-write fields. In addition, there is an extra 
'method' provided that returns a reference to a blank 
FL_EditKeymap object:

C<	$keymap = X11::Xforms::FLEditKeymap-E<gt>new;>

The idea here is to use the 'new' method to create
the object, use the I<$ref-E<gt>field> syntax to set the
edit key mapping requirements, and then pass the
object to the fl_set_input_editkeymap function. 

See the XFgrep.pl and X4Pinit.pl DEMOs for examples of how 
to use this (especially useful for making Linux Delete and
Backspace keys behave themselves!).

=back


Note that just because a field is read-write does not mean that
you SHOULD write to it. Refer to the Xforms documentation for details
of the use of each field, and if and when a field should be written
to.  

=head1 VALUE ADDED FEATURES

B<X11::Xforms> provides two powerful extra features over and above those delivered with the
native Xforms library. They exist separately but are designed to be used together.

TRY THIS: Once you have installed B<X11::Xforms>, run the demos. Then copy the
B<X4Pinit.pl> demo script to your home directory, renaming it to B<.X4Pinit.pl>,
and re-run the demos: THAT is what these facilities are all about!!

=head2 The Class Initialization Callback

Xforms does not provide a very easy way to apply system
wide defaults to object attributes, such as color and font. If you don't want what
is provided as the library default you have to set every object manually.

The B<Class Initialization Callback> feature solves this problem for Perl 
scripts.