-----Original Message----- From: Ashley Sheridan [mailto:ash@xxxxxxxxxxxxxxxxxxxx] Sent: 19 August 2009 03:34 PM To: arno@xxxxxxxxxxxxxx Cc: 'Dengxule'; 'Php Maillist' Subject: RE: How to make sure that the target file to read is not under writing by others? On Wed, 2009-08-19 at 15:31 +0200, Arno Kuhl wrote: > (any computer would instantly crash if that sort of basic housekeeping > wasn't done) No, it really wouldn't! If it did, then you'd never have video playing software out there that supported broken downloads, no preview software for semi-downloaded items. Have you ever been sent a large jpeg over a slow connection on a messenger program? You can open the file way before it's finished downloading and actually see it progressively load in. Thanks, Ash http://www.ashleysheridan.co.uk ------- If anyone was left a bit unsure about whether or not a write command in PHP could result in a file on a local filesystem being left in a semi-written state (i.e. some other script started reading the file while your script had only written part of its output string) rest assured that fwrite() always writes *all* the contents to the file without the need of flock(), by the time any other process (whether PHP or not) reads that file (assuming you're not writing megabytes of data with a single fwrite()). To quote the PHP manual: "If handle was fopen()ed in append mode, fwrite()s are atomic (unless the size of string exceeds the filesystem's block size, on some platforms, and as long as the file is on a local filesystem). That is, there is no need to flock() a resource before calling fwrite(); all of the data will be written without interruption." Cheers Arno -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
