X-Recipient: archive-cygwin AT delorie DOT com X-Spam-Check-By: sourceware.org Date: Thu, 15 Jul 2010 01:49:52 -0400 From: Christopher Faylor To: cygwin AT cygwin DOT com Subject: Re: Problem with select() on console Message-ID: <20100715054952.GB10561@trixie.casa.cgf.cx> Reply-To: cygwin AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com References: <4C3E59E3 DOT 4050003 AT hones DOT org DOT uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4C3E59E3.4050003@hones.org.uk> User-Agent: Mutt/1.5.20 (2009-06-14) Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com Delivered-To: mailing list cygwin AT cygwin DOT com On Thu, Jul 15, 2010 at 01:44:19AM +0100, Cliff Hones wrote: >When select() is used to test for input availability on the standard >cygwin console in normal (cooked) mode, it indicates input is available >as soon as any key is pressed. However, a call to read(0,...) >will (correctly) block until a terminating RETURN is entered. > >select() should only indicate input is available when a call >to read would *not* block - ie when a read call will immediately >return at least one character or an error such as EOF. > >The behaviour of the following test case illustrates this. When run >in a console window typing a single key causes the program to wait >for the whole line. When run under mintty or on Linux the >select() calls will continue to return no input until RETURN is >entered. Since, AFAIK, Windows has no way to do this, I don't see how it could be done easily. You could, I guess, pull characters into a buffer until a newline was found but that would be pretty error-prone and any use of select() would potentially invalidate console i/o for subprocesses. So, I don't see this changing anytime soon. cgf -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple