Re: Re: Filename from filehandle?

Could you talk more about "And beware of flock'ing filehandles that are already open... "?

I don't think I've ever applied a lock routine more than once. But now you've got my curiousity. What symptoms might occur if at some point I mess up and flock a file for the second time.

Sign me curious
Claude

Comment on Re: Re: Filename from filehandle?

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Re (tilly) 3: Filename from filehandle? by tilly (Archbishop) on Apr 25, 2001 at 02:25 UTC
Here is the idea of what can happen: `STEP 1: Wait for the first lock to be lost. STEP 2: Lose the first lock STEP 3: (Why don't we get here?)...` [download] This state of affairs is known as a "deadlock" and is usually considered Not Good.	[reply] [d/l]
Re: Re: Re: Filename from filehandle? by clintp (Curate) on Apr 25, 2001 at 05:01 UTC
Filehandles that are already opened (especially for writing) have may have already been modified, before the lock was applied. Consider: `open(FOO, ">/tmp/foo") \|\| die; # You've altered the file! flock(FOO, LOCK_EX) \|\| warn; # And now you bother to lock it?` [download] Yeah, it's silly. But you'd be amazed at how often it happens.	[reply] [d/l]