Re: Patch request to qt 5.9.4 (Re: [ANNOUNCEMENT] Qt 5.9.4)
- Date: Wed, 6 Mar 2019 08:58:25 +0900 (JST)
- From: Tatsuro MATSUOKA <tmacchant2@xxxxxxxxxxx>
- Subject: Re: Patch request to qt 5.9.4 (Re: [ANNOUNCEMENT] Qt 5.9.4)
> From: Achim Gratz
> To: cygwin
> Date: 2019/3/6, Wed 04:24
> Subject: Re: Patch request to qt 5.9.4 (Re: [ANNOUNCEMENT] Qt 5.9.4)
>T atsuro MATSUOKA writes:
>> I contacted with Enrico who tells me the patch that I have shown.
> Yes, but that monkeys around the real problem. What Yaakov is telling
> you is that there are two options and we don't know yet which one we
> have to deal with.
> If O_NONBLOCK is needed, but does not work correctly under Cygwin, then
> that's a bug in Cygwin. For this case, Corinna asks you to create an
> STC that demonstrates the bug so it can be triaged without having to
> work with something as complex as the Qt terminal in Cygwin.
> If on the other hand O_NONBLOCK is in fact not needed and just shows
> different behaviour on different systems without a bug in the
> implementation being present, then upstream should remove that argument.
Here I desribe another discussion on Bug tracker on gnuplot
My summary from searching through the history shown in the links above:
* gnuplot calls QLocalSocket::connectToServer("name")
* Qt tries to open a named pipe for the socket using O_NONBLOCK
* This fails because Cygwin has problems with non-blocking named
pipes. Back in 2010 Enrico Forestieri posted some simple examples of
this (standalone tests, no involvement of gnuplot code) but this
apparently did not lead to a fix.
* the Qt patch at the head of this bug report would make gnuplot work, but needs to be wrapped in a conditional test for CYGWIN. I can
understand why upstream Qt would not want to deal with this.
Conclusion: We probably can't fix it in the gnuplot code. There is a trivial work-around that requires modifying the Qt source code, but
this would only make sense for the purpose of making a Qt package
specifically for Cygwin.
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