I am trying to write a form to file that is going to have a heavy load and I think I need to use flock to prevent the file being written to while operations are carried out on it. I have this code from the o'reilly book:<br><FONT FACE=monospace><br>$LOCK_SH = 1;<br>$LOCK_SH = 2;<br>$LOCK_SH = 4;<br>$LOCK_SH = 8;<br><br>sub lock{<br> flock MBOX, $LOCK_EX;<br> seek MBOX, 0, 2;<br>}<br><br>sub unlock{<br> flock MBOX, $LOCK_UN;<br>}<br><br>open MBOX, ">>/usr/spool/mail/$env{'USER'}" or die "Can't open mailbox: $!";<br><br>lock()<br>print MBOX $msg, "\n\n";<br>unlock();<br></font><br>But I don't know what any of the bit's do. Could someone explain this to me? Also, I need to apply a lock to my own specified file, rather than a mailbox.<br><br>Thanks<br>Will <p>fortytwo<br><a href=mailto:will@hellacool.co.uk>will@hellacool.co.uk</a><br><a href= test site</a><br>
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What is all this flock stuff then? 1
- Thread starter fortytwo
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flock $my_file, $locking_mode<br><br>will lock your own file for you - assuming that the variable $my_file contains the right filename and the variable $locking_mode holds the right value.<br><br>the seek business positions the filepointer to the end of the file.<br><br>If it's really busy - use a database - flock is a pain and not very portable. <p>Mike<br><a href=mailto:michael.j.lacey@ntlworld.com>michael.j.lacey@ntlworld.com</a><br><a href= Cargill's Corporate Web Site</a><br>
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Got any more information on the possible values of flock (and what they do)?<br><br>Thanks<br>Will Jessop <p>fortytwo<br><a href=mailto:will@hellacool.co.uk>will@hellacool.co.uk</a><br><a href= test site</a><br>
not in work for the next couple of days - back in thursday - will look then if you still need help - sorry <p>Mike<br><a href=mailto:michael.j.lacey@ntlworld.com>michael.j.lacey@ntlworld.com</a><br><a href= Cargill's Corporate Web Site</a><br>
Will,<br><br>You still need help with this?<br><br>Mike<br> <p>Mike<br><a href=mailto:michael.j.lacey@ntlworld.com>michael.j.lacey@ntlworld.com</a><br><a href= Cargill's Corporate Web Site</a><br>
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Yeah, if that's OK 
<p>fortytwo<br><a href=mailto:will@hellacool.co.uk>will@hellacool.co.uk</a><br><a href= test site</a><br>
<p>fortytwo<br><a href=mailto:will@hellacool.co.uk>will@hellacool.co.uk</a><br><a href= test site</a><br>Will,<br><br>Try <FONT FACE=monospace><b>perldoc perlfunc</font></b> and then search for <FONT FACE=monospace><b>flock</font></b>, keep on skipping to the next occurrence of <FONT FACE=monospace><b>flock</font></b> until you reach the function definition. There's quite a bit of info there. <br><br>Shout up if it's all greek to you. <p>Mike<br><a href=mailto:michael.j.lacey@ntlworld.com>michael.j.lacey@ntlworld.com</a><br><a href= Cargill's Corporate Web Site</a><br>
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Thanks. Will Do. <p>fortytwo<br><a href=mailto:will@hellacool.co.uk>will@hellacool.co.uk</a><br><a href= test site</a><br>
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