Re: DISPLAY environment variable

[Jon Trowbridge <trow emccta com>]

On Tue, Apr 04, 2000 at 03:38:15PM -0700, Derek Simkowiak wrote:
> > >| Behavior of my X is very strange. It sets =DISPLAY= variable to value
> > >| ``unix:0.0''. I have no idea who made it (gdm, gnome or enlightenment)
> > 
> > >"unix:0" is legal (if old-fashioned) and means the same thing as ":0".  If 
> > >you have something which is confused by this then it is broken.

> 	"unix:0" is neither old-fashioned (it's necessary anytime you want
> to run a program remotely on a host named "unix") nor is it the same as
> ":0".

No.  Historically, "unix:0" is the same as ":0" and tells the system
that the X clients and X server are running on the same machine.  This
information can be used for various optimizations, such has having the
clients and server talk to each other over a (faster) Unix domain
socket rather than a TCP socket.

I'd be shocked if modern incarnations of X didn't just check if
everything is running on the same host and then automatically do the
right thing.  And hardware is so much faster now that using the
suboptimal form of IPC probably wouldn't cause noticeable performance
degradation.  But this sort of thing mattered once upon a time: I
can remember running X back in the 80's on machines where you could
really tell the difference between DISPLAY being settings of
"unix:0.0" and "whatever_the_hostname_was:0.0".

So if you have a machine named "unix" on your network, I guess you'd
have to set DISPLAY to "unix.mydomainname.com:0"... yet another reason
not to use "unix" as a hostname.

-JT

-- 
GNU/Linux: Free your mind and your OS will follow.