RE: change cursor type

[Drew Adams]

> > I want to change the cursor from box to bar style. Apparently, the
> > variable cursor-type is not a "user-option" variable and so doesn't
> > respond to M-x set-variable. I'm not clear on this distinction between
> > user-option and "non-user-option" variables, and the manual doesn't
> > seem to say anything about it (I could be mistaken but I didn't find
> > anything). Can anyone tell me how to change the value of cursor-type
> > to "bar"? I'd like the change to be global.

A user option is a variable defined using `defcustom', not `defvar'.
A user option is intended to be changed by users.  It can be customized
easily, using `M-x customize-option'.  It can also be set using
`set-variable'.

Any variable can be set by a user, using
`M-: (setq THE-VAR THE-NEW-VALUE)'.  Users can change any variable
they like, but it is not necessarily a good idea to do so.

Some variables that are not user options could be, arguably.
In older versions of Emacs, `cursor-type' was not even a variable;
it was only a frame parameter.  In Emacs 22 (it might have been 21)
`cursor-type' became a variable (it is still a frame-parameter also).
As of Emacs 24.3, `cursor-type' is not an option, but you can change
it without problems.

In Emacs 24.4 (not yet released) `cursor-type' will be a user option.

See the Emacs manual, node `Easy Customization' for information about
options vs other variables.