GLX and libX11

[Marco Atzeri]

On 25.01.2021 00:46, Michael Enright wrote:
> On Sun, Jan 24, 2021 at 5:38 AM Marco Atzeri via Cygwin
> <cygwin@cygwin.com> wrote:
>>
>>
>> Have you started the program from inside a XTerm  with a running
>> XServer ?
>>
> 
> I compiled and ran the program in a mintty window, while X server was
> started and the environment variable DISPLAY was set. It ran
> perfectly. I don't have XTerm installed, it would probably have taken
> care of the DISPLAY variable.
> 
> I started a second mintty window and started the program from there
> without setting DISPLAY, and the program complained "cannot connect to
> X server".
> 
> I think Rafał started the program from a shell which had DISPLAY set,
> but @Rafał if you could confirm that it would help a bit. I think some
> Cygwin X components may be missing. The reason I think this is the
> message that says the Windows DRI extension is missing, which I guess
> is awfully specific.
> 
> It occurs to me that starting XTerm would be a useful diagnostic, but
> if "Windows DRI" is missing, XServer probably can't start, never mind
> "Windows DRI extension"
> 

you are likely right, I will bet on "dri-drivers" not be
properly installed or having problems

$ cygcheck -cd |grep -i DRI
dri-drivers                             19.1.6-1
libdbi-drivers                          0.9.0-2
libxcb-dri2-devel                       1.14-1
libxcb-dri2_0                           1.14-1

as it should be pulled by libGL

$ cygcheck-dep -q -S -n dri-drivers
  dri-drivers: is needed for ( libEGL1 libGL1 tigervnc-server 
xorg-server-common )

Regards
Marco