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[87.249.164.127]) by smtp.gmail.com with ESMTPSA id r9sm2873367ljd.10.2020.03.27.07.53.36 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 27 Mar 2020 07:53:37 -0700 (PDT) From: To: "'Ken Brown'" Cc: "'cygwin'" References: <1b1401d60296$2769e690$763db3b0$@gmail.com> <716e2076-f607-454e-2723-937c3959e2a3@cornell.edu> <18be01d602ab$0bbfca30$233f5e90$@gmail.com> <35b43b59-6410-f21f-710c-385e39cbae0b@cornell.edu> <005201d603ba$2bc8ab20$835a0160$@gmail.com> <472d1df6-531a-ebd7-4ffa-583a06e270ff@cornell.edu> In-Reply-To: Subject: Sv: Sv: Sv: Named pipes and multiple writers Date: Fri, 27 Mar 2020 15:53:36 +0100 Message-ID: <00b901d60447$7ecb4c50$7c61e4f0$@gmail.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_NextPart_000_00BA_01D6044F.E08FDB60" X-Mailer: Microsoft Outlook 16.0 Thread-Index: AQJE9fQg8TMZuJRGwTEKbo0ZGNgDeQHtMggPA01jw/MCH/KUAAKPevBvAf/qW+kC4eksHQHeBGSzpvlSQYA= Content-Language: en-gb X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: cygwin@cygwin.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: General Cygwin discussions and problem reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 27 Mar 2020 14:53:41 -0000 This is a multipart message in MIME format. ------=_NextPart_000_00BA_01D6044F.E08FDB60 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable >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.ivarsson@gmail.com wrote: >>>> The ENIXIO occurs when parallel child-processes simultaneously = using=20 >>>> O_NONBLOCK opening the descriptor. >>> >>> This is consistent with my guess that the error is generated by=20 >>> fhandler_fifo::wait.=A0 I have a feeling that read_ready should have = >>> been created as a manual-reset event, and that more care is needed = to=20 >>> make sure it's set when it should be. >>> >>>> I could provide a code-snippet >>>> to reproduce it if wanted ? >>> >>> Yes, please! >>=20 >> That might not be necessary.=A0 If you're able to build the git repo=20 >> 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 =20 >Ken ------=_NextPart_000_00BA_01D6044F.E08FDB60 Content-Type: text/plain; name="pipe.cpp" Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="pipe.cpp" #include #include #include #include #include #include #include namespace { auto error(const int error) { std::cerr << getpid() << "\terror:\t" << error << '\t' << = std::strerror(error) << std::endl; return error; } } int main() { const auto name{"/tmp/my_name"}; const auto result =3D mkfifo(name, 0666); if(result) return error(errno); constexpr auto writers{5}; constexpr auto messages{4}; for(auto idx =3D 0; idx < writers; ++idx) { const auto pid =3D fork(); if(pid < 0) return error(errno); if(pid =3D=3D 0) { std::cout << "child " << getpid() << std::endl; for(auto idx =3D 0; idx < messages; ++idx) { const auto wfd =3D open(name, O_WRONLY | O_NONBLOCK); if(wfd < 0) return error(errno); const auto msg{std::to_string(getpid())}; if(write(wfd, msg.data(), msg.size() + 1) < 0) error(errno); close(wfd); } return 0; } } { std::cout << "parent" << std::endl; const auto rfd =3D open(name, O_RDONLY); const auto wfd =3D open(name, O_WRONLY); if(rfd < 0) return error(errno); for(auto idx =3D 0; idx < writers * messages; ++idx) { std::string buffer; buffer.resize(80); if(read(rfd, &buffer[0], buffer.size()) < 0) error(errno); std::cout << buffer << std::endl; } close(wfd); close(rfd); } if(unlink(name) < 0) return error(errno); return 0; } ------=_NextPart_000_00BA_01D6044F.E08FDB60--