From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf1-x12d.google.com (mail-lf1-x12d.google.com [IPv6:2a00:1450:4864:20::12d]) by sourceware.org (Postfix) with ESMTPS id 93151395C852 for ; Thu, 12 Mar 2020 01:04:39 +0000 (GMT) Received: by mail-lf1-x12d.google.com with SMTP id b186so3240197lfg.11 for ; Wed, 11 Mar 2020 18:04:39 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language; bh=IJcrlvWm0RVvv4AOzTx6WR67tla0ytJd76Q/xBTX1Ms=; b=Pbj7/iQtTlYxLCCYMNCn86/Z2RcjipGsA8NBsAXS2I7P/U2FHADkeitB3ynIYHpxZQ lB2IZmtlRz2T7kxCQgdgIuPqrhIDYC0qnaWl+npGzjLs+4uXqcnN+O2QJuGch5Ay6WTF V0OndIZ7LEHApLxxzMuNq4w5eYHepMtrmp7JKu/jBFRiGvWnXVmLCeeDRhHnr4H8ceM4 8HaK+G+zpUexEQ0+VnDepFpLvCRleuA9DKR9n9Z+oMrQOwLE/f+fTWHg7l37R4xF2DWp aI7kJn9tybPJOT9bUeNHB7xsi/SGNEPNN/gwXp8++i1MuwuQir/5XW9NRa2yDFmMV/AB A7Qw== X-Gm-Message-State: ANhLgQ0gFU+PhQqYkUAOehwsJqcwKLR4oKWmXj+JyTyt7gX9nWSoY9+I oU/ADYnYjCEOIkmwMHMkUnnOZuuvgFw= X-Google-Smtp-Source: ADFU+vvCPlS5VEENAXWvZs0tOd6RbR2HPxjK3ug2CSQoEvsVbgvYkFMHbZtsnN8QaeKhKM286vyfQw== X-Received: by 2002:ac2:5dd8:: with SMTP id x24mr1850326lfq.180.1583975077982; Wed, 11 Mar 2020 18:04:37 -0700 (PDT) Received: from [192.168.1.117] (tb213-185-244-58.cust.teknikbyran.com. [213.185.244.58]) by smtp.googlemail.com with ESMTPSA id r10sm13328222ljk.13.2020.03.11.18.04.37 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 11 Mar 2020 18:04:37 -0700 (PDT) Subject: Re: Setting termios VMIN > 0 and VTIME > 0 on non blocking file To: cygwin@cygwin.com References: <9e4c6428-59de-df07-9e33-44ba95d5497f@gmail.com> <5be321d9-10c2-0853-b716-2abd10a4db3a@SystematicSw.ab.ca> From: =?UTF-8?Q?=c3=85ke_Rehnman?= Message-ID: <5541b350-9992-a0cf-ca77-43a0df83c0a8@gmail.com> Date: Thu, 12 Mar 2020 02:04:34 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <5be321d9-10c2-0853-b716-2abd10a4db3a@SystematicSw.ab.ca> Content-Language: en-US X-Spam-Status: No, score=-1.8 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, HTML_MESSAGE, HTML_OBFUSCATE_05_10, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Content-Filtered-By: Mailman/MimeDel 2.1.29 X-BeenThere: cygwin@cygwin.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Cygwin mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 12 Mar 2020 01:04:41 -0000 On 2020-03-11 22:55, Brian Inglis wrote: > VMIN > 0 || VTIME > 0 implies blocking; O_NONBLOCK implies SIGIO > delivery; see: > https://www.tldp.org/HOWTO/pdf/Serial-Programming-HOWTO.pdf > https://www.cmrr.umn.edu/~strupp/serial.html > https://en.wikibooks.org/wiki/Serial_Programming/termios > > also read the man pages carefully and *assume* nothing; functions should work > *exactly* as documented: there be dragons! > According to https://www.cmrr.umn.edu/~strupp/serial.html "*Timeouts are ignored in canonical input mode or when the/NDELAY/option is set on the file via/open/or/fcntl/."* This leads me to believe the current cygwin implementation is not correct. Changing the VMIN and VTIME should have no effect on the read() behavior if the file was opened with O_NOBLOCK. ** * *