Cygwin/X on Windows 10 won't launch apps from .XWinrc menus

[Roland Roberts]

On 8/19/2021 2:41 PM, Eliot Moss wrote:
> On 8/18/2021 7:19 PM, Roland Roberts wrote:
>> On 8/10/2021 8:58 AM, Roland Roberts wrote:
>>> I have a new, company-supplied Windows 10 laptop, using Cygwin to do 
>>> development. I’m having a problem getting XWin to launch apps. XWin 
>>> appears to be mostly working normally, meaning if I launch a Cygwin 
>>> mintty instance, I can manually set DISPLAY=:0.0 and start up X 
>>> application from the shell prompt. But trying to launch from my 
>>> .XWinrc, the application never displays and I can’t find a useful 
>>> error log to track down the issue. I’m pretty sure it’s some 
>>> permission someplace my account doesn’t have (and I can probably get 
>>> IT to change that if I can just identify what it is).
>>>
>>> [...]
>>>     [  1490.390] executing '/bin/mintty', pid 772
>>>     [  1902.312] executing '/bin/mintty', pid 1200
>>>
>>> You can see the last two things that were launched. And here’s the 
>>> process list
>>>
>>>   [...processes show XWin starting, never spawns child mintty...]
>>>
>>> Any suggestions on where to poke to diagnose this? My home Windows 
>>> 10 machine has no problem at all. Oh, and cygcheck report version 
>>> 3.1.4. Yes, that’s a little old, but we are stuck there until we can 
>>> work out an issue with our build environment and the change for 
>>> 3.1.5+ in how symlinks are handled.
>>>
>> So, no suggestions :-(
>>
>> I'm looking for anything at all that I could put into my .XWinrc that 
>> might produce some diagnostic output short of running XWin under a 
>> debugger. I'm completely guessing that it's a permission thing.
>>
>> As I mentioned, I *can* launch X applications from a Cygwin mintty 
>> shell console after setting DISPLAY, including being able to launch 
>> things like Emacs, so whatever is stopping these from displaying, 
>> it's only affecting things launched from my .XWinrc.
>
> A wondering:
>
> - How are the programs mentioned in the .XWinrrc file?


I've tried both with "mintty" and with "/bin/mintty". Makes no visible 
difference. And yes, that path is correct. /bin/emacs -> 
/etc/alternatives/emacs -> /usr/bin/emacs-X11


> - Is /usr/bin on the PATH when XWin is started?

Yes.

> I recall having issues around the PATH at some point ...

I almost certainly did, too, which is why my launch shortcut looks like this

C:\cygwin64\bin\run.exe --quote /usr/bin/bash.exe -l -c "cd; exec 
/usr/bin/startxwin"

That gives me a login shell which means my .bashrc gets executed. That's 
a bit heavy and has it's own potential pitfalls. But... I have moved 
aside my .bashrc and it makes no difference.

In fact, I cna run startxwin from a mintty/bash shell and it works 
flawlessly. The above Windows 10 launch shortcut is what I'm using on 
both my work machine (where nothing will launch) and my home machine 
(where it works just fine)

My problem sounds a lot like the Cygwin/X FAQ 
https://x.cygwin.com/docs/faq/cygwin-x-faq.html#q-startxwin-no-windows

Except that starting it from a mintty/bash windows works so that sheds 
no light on the failure :-(

roland


-- 
Roland Roberts, PhD
Brooklyn, NY USA
https://astrofoto.org