Proposed change to gud-display-line

[Nick Roberts]

I intend to change the last operation in gud-display-line:        

(set-window-point window overlay-arrow-position)

to

(if window (set-window-point window overlay-arrow-position))

This should not affect its use when gud-minor-mode is not 'gdba as
gud-display-line does a display-buffer earlier, which ensures that
window is non nil. I want this line to do nothing when I am not
displaying source, i.e using M-x gdba and displaying machine code.

This relates to a post on comp.emacs which says:

> Hello, 

> i noticed that 

> (with-current-buffer buffer
>   (forward-line n))

> only works if buffer is not visible in any windows.  Is this a bug or
> a feature?  Does anyone know a good workaround?

> I'm using 

> GNU Emacs 21.3.2 (i386-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
>  of 2003-04-24 on raven, modified by Debian

> Regards, 

> David

I can see there might be ambiguities if there is more than one window for the
given buffer but this behaviour could give unexpected results.

Nick