Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm 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 Message-ID: <416D1B95.8050901@x-ray.at> Date: Wed, 13 Oct 2004 14:12:05 +0200 From: Reini Urban User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; de-AT; rv:1.8a3) Gecko/20040817 MIME-Version: 1.0 To: Nuno Leitao CC: "'cygwin AT cygwin DOT com'" Subject: Re: Buffered output/Forked processes References: <8904DDEEB811D6118AF900508BB832FA080995E0 AT the-exch-c DOT ai DOT pri> In-Reply-To: <8904DDEEB811D6118AF900508BB832FA080995E0@the-exch-c.ai.pri> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Nuno Leitao schrieb: > I have a Perl script which looks like: > > open( VMSTAT, "vmstat 5|" ); > VMSTAT->autoflush( 1 ); > while( ) { > print $_; > } > > Now, under Linux and other UNIX OS's this works fine, and "print $_" will > print the vmstat output every 5 seconds since the output from vmstat is not > buffered. Under Cygwin however, it seems vmstat will always buffer its > stdout with the undesirable effect that lines come in batches as the output > buffer gets full and is flushed by the Cygwin C libraries. > > Is there a way to go around this without having to patch and recompile > vmstat or other binaries I might want to use in this way ? basic perl question, not cygwin related. $ perldoc -q buffer $ perldoc -f select cygwin perl doesn't honor $| ? not true. Because you told VMSTAT not to buffer. But you shold have told it to STDOUT. open( VMSTAT, "vmstat 5|" ); VMSTAT->autoflush( 1 ); $| = 1; # STDOUT is selected so STDOUT will get unbuffered. while( ) { print $_; } -- Reini Urban http://xarch.tu-graz.ac.at/home/rurban/ -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/