On 3/28/2020 11:43 AM, Ken Brown via Cygwin wrote:
On 3/28/2020 8:10 AM, sten.kristian.ivars...@gmail.com wrote:
On 3/27/2020 10:53 AM, sten.kristian.ivars...@gmail.com wrote:
On 3/26/2020 7:19 PM, Ken Brown via Cygwin wrote:
On 3/26/2020 6:39 PM, Ken Brown via Cygwin wrote:
On 3/26/2020 6:01 PM, sten.kristian.ivars...@gmail.com wrote:
The ENIXIO occurs when parallel child-processes simultaneously
using O_NONBLOCK opening the descriptor.
This is consistent with my guess that the error is generated by
fhandler_fifo::wait. I have a feeling that read_ready should have
been created as a manual-reset event, and that more care is needed
to make sure it's set when it should be.
I could provide a code-snippet
to reproduce it if wanted ?
Yes, please!
That might not be necessary. If you're able to build the git repo
master branch, please try the attached patch.
Here's a better patch.
I finally succeeded to build latest master (make is not my favourite
tool) and added the patch, but still no success in my little
test-program (see
attachment) when creating a write-file-descriptor with O_NONBLOCK
Your test program fails for me on Linux too. Here's the output from one
run:
You're right. That was extremely careless of me to not test this in Linux
first :-)
No problem.
I can assure that we have a use case that works on Linux but not in Cygwin,
but it seems like I failed to narrow it down in the wrong way
I'll try to rearrange my code (that works in Linux) to mimic our application
but in a simple way (I'll be back)
OK, I'll be waiting for you. BTW, if it's not too hard to write your test case
in plain C, or at least less modern C++, that would simplify things for me. For
example, your pipe.cpp failed to compile on one Linux machine I wanted to test
it on, presumably because that machine had an older C++ compiler.
Never mind. I was able to reproduce the problem and find the cause. What
happens is that when the first subprocess exits, fhandler_fifo::close resets
read_ready. That causes the second and subsequent subprocesses to think that
there's no reader open, so their attempts to open a writer with O_NONBLOCK fail
with ENXIO.
I should be able to fix this tomorrow.
Ken
--
Problem reports: https://cygwin.com/problems.html
FAQ: https://cygwin.com/faq/
Documentation: https://cygwin.com/docs.html
Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
