X11 app - unable to open display ""

[Chris Jones]

On 17/04/2019 10:06 am, Christoph Kukulies wrote:
> I installed the „gv“ port (ghostview). Worked.  I can give gv on the 
> command line (shell prompt).
> But I’m getting:
> 
> Christophs-MBP:~ kuku$ export DISPLAY=:0
> Christophs-MBP:~ kuku$ xhost +
> xhost:  unable to open display ":0"
> Christophs-MBP:~ kuku$ gv
> gv: Unable to open the display.
> Christophs-MBP:~ kuku$
> 
> I thought, X11 apps can run against the macOS desktop server, can’t they?
> Or do I have to run an extra X11-server?

I am not sure exactly what you mean by this, but X11 applications cannot 
connect directly to the native (Quartz) window manager in macOS. You 
need to run an X11 server on top. Have you installed one of these, 
either XQuartz from

https://www.xquartz.org/

or (better these days as the above is effectively no longer maintained) 
just run

 > sudo port install xorg-server

to install the MacPorts version (which is more up to date than XQuartz) 
?? If not, please do this now (I recommend the MP one).

Then, log out and back in again (yes, this is really required).

Then, just start whatever X11 application you want, no setting DISPLAY 
or anything like that, and the X11 server will automatically start.

Chris

> 
> —
> Christoph
> 
>