[Interest] Qt 5.6.0: Strange "QProcess: CreateNamedPipe failed. (access denied)" messages

[Rainer Wiesenfarth]

2016-11-10 17:08 GMT+01:00 Joerg Bornemann <joerg.bornemann at qt.io>:

> On 09/11/2016 14:24, Rainer Wiesenfarth wrote:
>
> Environment 1: Windows 10.
>> - Dad starts first instance of Son => error message from Qt "QProcess:
>> CreateNamedPipe failed. (access denied)" (3 times)
>>
>
> This indicates that the pipes for stdin/stdout/stderr could not be created
> for whatever reason. Would it be possible to provide an example that
> exhibits the issue?
>

​I attach the four files I also added to the issue created with Qt support.
Unfortunately, they could not reproduce the observed behavior on Windows
10. Here the text of the support issue:

I create multiple QProcess instances from a worker thread, tying their
> output
> to the GUI. With Windows 7 this works as expected.
> With Windows 10 the first (and only the first!) attempt fails, issueing
> three
> warnings "QProcess: CreateNamedPipe failed. (access denied)" and
> showing no output of this first child process. However, any subsequent try
> on
> Windows 10 then also succeeds.
> I attached two example programs (parent and child) and screenshots of both
> Windows 7 and Windows 10.
> Please build the child and parent program and place them in the same
> folder,
> then start the parent. Clicking the "Create Child" button stimulates
> the desired action.


​I ran the test on multiple machines with both Windows 7 and Windows 10,
but ran into that issue only on one of them​. I would be happy if you could
run the test on other machines (preferably Windows 10) to help locating the
reason for this behavior.


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